Turning an old car into a powerful generator(blog.arduino.cc)
blog.arduino.cc
Turning an old car into a powerful generator
https://blog.arduino.cc/2023/09/20/turning-an-old-car-into-a-powerful-generator/
294 comments
If you want to do this, you should put a gear box between the engine and generator. Sure your car engine can run at 3600 rpm (I've seen exceptions, but they are rare), but typically it is most fuel efficient when run at closer to 2000 rpm at high load. At lower loads lower RPM is more efficient (but not as efficient as high load at 2000 rpm) - but your car probably doesn't have a large enough cooling system to handle high loads for very long, so perhaps run the engine at 1800 rpm and use a 1:2 gear box to get the right rpm for the generator, which makes design simple and is "close enough" to ideal without needing to see the exact efficient/power/rpm curves of your particular engine (a 3d graph).
You're right that the best Brake Specific Fuel Consumption (BSFC) occurs at higher loads. If anyone wants to see a map of this, search for "brake specific fuel consumption map". More modern engines might actually have their peaks closer to 3000RPM due to improved technology. The trend is toward smaller engines that rev higher, so peak efficiency is steadily shifting to the right.
However, it probably doesn't matter due to the extreme mismatch between the engine's output and the generator's maximum power.
The generator appears to be rated at 5500W, which is 7.4HP. Efficiency of electrical generators is high, so we'll call the load 8HP maximum.
An Toyota Sienna engine has a peak power output around 200HP.
For reference, a car air conditioning system might consume around 4HP, or half of this generator's load. The generator is barely more than running the air conditioning.
So ideally, you'd pick a set of pulleys that let the engine basically idle. The goal is to minimize internal engine losses at this level, because you're nowhere near the peak efficiency islands on the BSFC map.
However, it probably doesn't matter due to the extreme mismatch between the engine's output and the generator's maximum power.
The generator appears to be rated at 5500W, which is 7.4HP. Efficiency of electrical generators is high, so we'll call the load 8HP maximum.
An Toyota Sienna engine has a peak power output around 200HP.
For reference, a car air conditioning system might consume around 4HP, or half of this generator's load. The generator is barely more than running the air conditioning.
So ideally, you'd pick a set of pulleys that let the engine basically idle. The goal is to minimize internal engine losses at this level, because you're nowhere near the peak efficiency islands on the BSFC map.
Wow, I had no idea that a car engine produced more than a hundred kilowatts of power, that's ridiculous! (For comparison, an average household consumes something like tens of kilowatt hours per day, so driving for an hour (I guess at peak, which an engine wont always be) may be similar to 5 or 10 days of a household's power usage, and not to mention much less efficiently generated.
Modern cars are powerful. Today there's no car on the market today that doesn't have enough power. The cheapest cars you can buy, small sub $20k hatchbacks, are all around 100kw. They all have performance figures that beat sports cars from the 1970s.
The limiting factor on early acceleration (0-60kph) today for all cars is now tyres. Beyond that air resistance might make more engine power matter but in general it's all about the tyres. Every car can spin their wheels at the lights if they want to. If you feel the need to floor it at the lights you're showing off your tyres not your engine power (and also wearing them out).
The limiting factor on early acceleration (0-60kph) today for all cars is now tyres. Beyond that air resistance might make more engine power matter but in general it's all about the tyres. Every car can spin their wheels at the lights if they want to. If you feel the need to floor it at the lights you're showing off your tyres not your engine power (and also wearing them out).
Fiat Panda and Renault Twingo start around 50 kW.
Sub $20k vehicles do not exist in this day and age.
Nissan Versa is 16k. Kia Rio is 17k. Mitsubishi Mirage is 17k.
https://www.caranddriver.com/features/g44830210/cheapest-new...
There may not be a LOT of cars in that price range but they definitely exist.
https://www.caranddriver.com/features/g44830210/cheapest-new...
There may not be a LOT of cars in that price range but they definitely exist.
Let me introduce to you tata tiag ev.
https://tiagoev.tatamotors.com/
A sub $10k "electric" vehicle that's essentially the best selling electric car in india right now because of it's price.
A 4 star global ncap rated car so not a death box btw
A sub $10k "electric" vehicle that's essentially the best selling electric car in india right now because of it's price.
A 4 star global ncap rated car so not a death box btw
0 to 60 in 5.7 .... a sub 10k car putting up the same numbers as a 1980s Ferrari Testarossa.
I'm embarrassed to have at one point unironically thought of myself as a serious Car Guy. EVs have done so much to expose mainstream male-oriented car culture as an utterly ridiculous and performative costume ball for manchildren.
I'm embarrassed to have at one point unironically thought of myself as a serious Car Guy. EVs have done so much to expose mainstream male-oriented car culture as an utterly ridiculous and performative costume ball for manchildren.
It's 0 to 60 in km/h* FYI
Oh thanks for pointing that out, I did not even notice they had switched units. When these comparisons are made normally if kilometers are being used as the unit then the zero to 100 time is given to make a comparable to miles. I don't think I've ever seen 0 to 60 times listed in kilometers per hour even in markets where km is the customary unit of distance. Is this something normally done for the Indian market? I suppose as 0 to 37-ish mph time of 5.7 seconds is respectable for travel on surface streets, but my joke comparison to the Testarossa rather falls down now. Assuming acceleration remains linear until 60 miles per hour then this little box will come in at just a hair over 9 seconds. Still, that puts it right in the same ballpark as a V8 powered Camaro from the mid 80s.
this is a family car. it is NOT supposed to be fast, heck it will spend most of its operating life running in less than 60 KMPH.
and yes, 0-100 KMPH is the standard because KM and not miles is the standard.
0-60 is for those chasing numbers, 0-40, 0-60, 0-100, these are all for those who want to advertise how fast a machine is or for breaking records.
indian roads are NOT for driving at 100 KMPH on a regular basis. highways and expressways but that is not normal driving in india
and yes, 0-100 KMPH is the standard because KM and not miles is the standard.
0-60 is for those chasing numbers, 0-40, 0-60, 0-100, these are all for those who want to advertise how fast a machine is or for breaking records.
indian roads are NOT for driving at 100 KMPH on a regular basis. highways and expressways but that is not normal driving in india
If india is anything like sri lanka, you'd be lucky to make 30 kmph.
[new cars]
And in many cases, that much power transports a single person and occasionally a few bags of groceries.
edit: By point of comparison, a good cyclist produces about 100 watts, probably less if they're on a leisurely cruise. That's about 2% of the wattage of a car engine.
edit: By point of comparison, a good cyclist produces about 100 watts, probably less if they're on a leisurely cruise. That's about 2% of the wattage of a car engine.
For more direct comparison, there are motorcycles on the market that can produce ~150kW , to transport about the same amount of stuff.
Bicycles are really efficient (and those motorcycles are very fast)
Bicycles are really efficient (and those motorcycles are very fast)
> And in many cases, that much power transports a single person and occasionally a few bags of groceries.
Is there any comparable mode of transport that can accommodate all of this in poor weather (i.e. a snowstorm) without having to wear burdensome clothing?
I realize 150 years ago people wouldn’t venture out in those conditions, but they also didn’t move more than 50 km from their birthplace over their lifetime.
Is there any comparable mode of transport that can accommodate all of this in poor weather (i.e. a snowstorm) without having to wear burdensome clothing?
I realize 150 years ago people wouldn’t venture out in those conditions, but they also didn’t move more than 50 km from their birthplace over their lifetime.
Yes: a bus or light rail system can carry tens or hundreds of people at a time for a comparable amount of wattage per person. Build the system underground and inclement weather becomes even less of an issue.
I live in a city that's often said to have the best public transit infrastructure in Europe and one of the best in the world.
I still use my car to go shopping and to transport myself. Carrying bags of groceries from the shop to the station, and from the station to my house is a lot of work and I'm not going to do that in bad weather.
And public transit is much slower than going by car. For example: My doctor (that I have to visit every 2 weeks) is 25 minutes away by car and 1.5h by public transit.
Don't trust stories about how you can work or read in public transit. The vehicles are so full in peak times that you're happy you at least get to fit into the vehicle.
And it's a thoroughly bad experience during summer, I am sensitive to smells and I just can't do it, the body odors are too much and I'd throw up immediately.
I still use my car to go shopping and to transport myself. Carrying bags of groceries from the shop to the station, and from the station to my house is a lot of work and I'm not going to do that in bad weather.
And public transit is much slower than going by car. For example: My doctor (that I have to visit every 2 weeks) is 25 minutes away by car and 1.5h by public transit.
Don't trust stories about how you can work or read in public transit. The vehicles are so full in peak times that you're happy you at least get to fit into the vehicle.
And it's a thoroughly bad experience during summer, I am sensitive to smells and I just can't do it, the body odors are too much and I'd throw up immediately.
I live in a city with one of the oldest but largest transport systems in Europe and if you’re near a rail (under or over ground) stop, public transport is usually quicker. For journeys within the inner zone, cycling is usually the next quickest and often quicker than public transit even. However, once you get to the outskirts (or late at night) and have to depend on the bus network, driving or private hire becomes quicker again.
I'm right next to rail, that's the 1.5h I was talking about. 3 changes on the way and the waiting time adds up.
Reminds me of a city I used to live in. Their bus system was actually really good on average, but the worst-case routes had two 30-minute layovers. Even in -40F drifting snow it was faster to walk across the city than take those trips, and you'd only really take the bus if you had a lot to carry or wanted to avoid the elements.
You're still going to want to bundle up for the parts where you're walking to or from the station. But it's not like that's difficult or burdensome to do, at least for anyone hale enough to walk a couple miles without trouble. I commuted to work daily via light rail for years; with a couple of well-thought-out layers, good gloves and shoes, scarf, and hat, you're good to go down to about 15°F in reasonably still weather, and by adding a parka and balaclava you can take that down to 0° and still be quite comfortable - and with a backpack or satchel, carry quite a lot besides.
(If anything, you might find yourself too warm and sweating! Working your muscles puts out a surprising amount of heat, and modern textiles can do an amazing job of keeping it where it does the most good.)
Frankly, this is a skill anyone should have who lives where it gets cold enough to be useful. You won't always get to know ahead of time when you might be out in the cold - after a car wreck, for example, and maybe without a running engine for a heater into the bargain - so it pays to dress for what you could end up needing, or at least have the parts of such an outfit close to hand against the chance you might.
(If anything, you might find yourself too warm and sweating! Working your muscles puts out a surprising amount of heat, and modern textiles can do an amazing job of keeping it where it does the most good.)
Frankly, this is a skill anyone should have who lives where it gets cold enough to be useful. You won't always get to know ahead of time when you might be out in the cold - after a car wreck, for example, and maybe without a running engine for a heater into the bargain - so it pays to dress for what you could end up needing, or at least have the parts of such an outfit close to hand against the chance you might.
Where do you life that snowstorms are a daily concern? McMurdo station?
I live in the middle of Europe.
Snowstorms are a daily concern for 2 months of a year.
Extreme heat is a daily concern for 2 months of a year, too.
And rain is a daily concern for 2-3 months of a year.
Snowstorms are a daily concern for 2 months of a year.
Extreme heat is a daily concern for 2 months of a year, too.
And rain is a daily concern for 2-3 months of a year.
Nice so you can cycle without worry for about half the year.
Not going to do that with groceries, and generally it takes too much time and effort (this city is built on a lot of hills) and is too dangerous around here. Nicer bikes get stolen a lot (I lost 3 before I lost my patience and didn't buy another one), cars are much harder to steal.
In my part of Canada, weekly or twice weekly snow events are a reality from late November to early April.
Nice so you can cycle for half a year without worrying about snowstorms.
I don’t hibernate for the other half of the year. I continue to cycle when weather permits. I might have been able to carry enough groceries for myself in two panniers, but it’s not practical for enough food my family.
A cargo bike might carry four or so grocery bins, but not the six to eight I now get on my biweekly shop.
A cargo bike might carry four or so grocery bins, but not the six to eight I now get on my biweekly shop.
The continuation of this thought is to realize what an immense amount of power there is in a gallon of gas. It is basically free energy compared to using serfs or beasts of burden to do the work.
I saw something the other day - the numbers aren't exactly right, but it was along the lines of there's the same amount of energy in a barrel of oil as one man working full time in a manual job FOR SEVEN YEARS.
This is why we've (unfortunately) built modern societies on fossil fuels. The amount of work done as a result of it is immense, and probably explains why there aren't vast numbers of people enslaved for manual labour any more.
This is why we've (unfortunately) built modern societies on fossil fuels. The amount of work done as a result of it is immense, and probably explains why there aren't vast numbers of people enslaved for manual labour any more.
It's maybe equally mind-blosing to consider the miniscule amount of mass required to generate equivalent energy in nuclear reactions.
This is very visible in EVs. They can power a house for multiple days, but last only few hours at highway speeds.
If you actually run it at that power constantly it's not going to last long though. It's peak power. You're not going to drag race your car, most of the time it's just cruising.
This is a big difference to (piston) airplane engines because those are designed to give near 100% a lot of the time.
This is a big difference to (piston) airplane engines because those are designed to give near 100% a lot of the time.
Yeah, marine boat engines (gas outboards -- NOT auxilliary diesels!) are designed to run close to full-throttle ~all the time.
Huh I didn't know that. I guess cooling is simple there considering they can just ingest cool water and expel it without having a radiator. I don't know much about boats.
It sounds easier than on piston planes even. They run pretty hot when running flat-out while parked, like during a run-up test. We were always told to only do it for 30 seconds or so.
They generally use air cooling and despite the huge "fan" on the front it struggles in this scenario. When you're doing 100 knots it's less of a problem.
It sounds easier than on piston planes even. They run pretty hot when running flat-out while parked, like during a run-up test. We were always told to only do it for 30 seconds or so.
They generally use air cooling and despite the huge "fan" on the front it struggles in this scenario. When you're doing 100 knots it's less of a problem.
petrol is roughly 9.5kW/litre (~35kWh/US gallon) if that's a better reference for consumption (of which maybe 30% will make it to energy through a modern engine?)
Its why having an EV hookup is so funny: your house is now a tiny percentage of your power bill/load dimensioning.
Also why I'd really like to have my car battery be usable by the house: storing solar or winter/night consumption all require a battery. You'll never need a bigger one for your house than the one already in your EV.
Also why I'd really like to have my car battery be usable by the house: storing solar or winter/night consumption all require a battery. You'll never need a bigger one for your house than the one already in your EV.
The rediculoussness of the energy use of transport is especially noticeable when you are driving a Tesla which by default shows you a dial of power consumption and generation in kW.
When rolling down a hill with regenerative breaking, the car is generating 50kW.
You can literally power many average homes with that.
When rolling down a hill with regenerative breaking, the car is generating 50kW.
You can literally power many average homes with that.
On the other hand, pedaling a bicycle, or pushing a car is a lot of work.
It's not ridiculous until you compare against people doing it manually.
also, teslas are really quite efficient and it's amazing how they recover energy as well.
I wonder if there are efficiencies to be had recovering energy to come, since they can only recover what the batteries can absorb.
It's not ridiculous until you compare against people doing it manually.
also, teslas are really quite efficient and it's amazing how they recover energy as well.
I wonder if there are efficiencies to be had recovering energy to come, since they can only recover what the batteries can absorb.
Pedalling a bike is not a lot of work. Old people do it daily.
Thrusting a car through air at 100kph though, that takes a lot of work. Drag scales with the square of the velocity and proportionally to the frontal surface area.
Cars are a fast, but woefully inefficient means of transport.
Thrusting a car through air at 100kph though, that takes a lot of work. Drag scales with the square of the velocity and proportionally to the frontal surface area.
Cars are a fast, but woefully inefficient means of transport.
> Drag scales with the square of the velocity
Drag force scales with the square of velocity. Drag power (rate of work or rate of energy consumption) scales with the cube of velocity.
Drag force scales with the square of velocity. Drag power (rate of work or rate of energy consumption) scales with the cube of velocity.
Good clarification thanks !
Perhaps you've never cycled up a hill.
Perhaps I've grown up in Europe and have been cycling my whole life.
You lose a lot of energy to drag, friction and resistance(aka: heat.) Battery capacities are almost never the limiting factor in this equation. This is especially so when you don’t top the battery off to begin with.
> On the other hand, pedaling a bicycle, or pushing a car is a lot of work.
One of these is not like the other. Pedalling a bike doesn't come even close.
Humans consume several million calories per day at most, now as a rule of thumb a million calories is about the same as a kWh. And the only reason they consume that much energy is because the human body is inefficient at converting this heat to work. Even the best cyclists struggle to produce anything more than a few hundred watt.
More to the point, humans struggle to power a light bulb, let alone a house.
One of these is not like the other. Pedalling a bike doesn't come even close.
Humans consume several million calories per day at most, now as a rule of thumb a million calories is about the same as a kWh. And the only reason they consume that much energy is because the human body is inefficient at converting this heat to work. Even the best cyclists struggle to produce anything more than a few hundred watt.
More to the point, humans struggle to power a light bulb, let alone a house.
> And the only reason they consume that much energy is because the human body is inefficient at converting this heat to work.
The human body does not convert heat to work. We do something entirely different (look up the "ATP/ADP cycle").
But yeah there are certainly conversion losses in the conversion of egg sandwiches to labor. 25% or so. Which is actually pretty good; you won't be able to match that with a steam machine built over the weekend (start with solving the problem of setting eggs on fire?).
The human body does not convert heat to work. We do something entirely different (look up the "ATP/ADP cycle").
But yeah there are certainly conversion losses in the conversion of egg sandwiches to labor. 25% or so. Which is actually pretty good; you won't be able to match that with a steam machine built over the weekend (start with solving the problem of setting eggs on fire?).
Of course it's ridiculous to have 300kW car engines racing from light to light averaging 10mph in the city when someone on a bike can do that faster with 100W.
300kw is peak power.
I think teslas are pretty efficient:
https://forum.abetterrouteplanner.com/blogs/entry/22-tesla-m...
A model 3 LR uses less than 100 watt hours to go 1 mile at 25mph
I wonder how efficient bikes become at higher speeds with respect to drag coefficient (without a streamlined fairing)
I think teslas are pretty efficient:
https://forum.abetterrouteplanner.com/blogs/entry/22-tesla-m...
A model 3 LR uses less than 100 watt hours to go 1 mile at 25mph
I wonder how efficient bikes become at higher speeds with respect to drag coefficient (without a streamlined fairing)
Only if the lights are stopping the car but not the cyclist. If you apply regulations that are designed to favour one contestant, it's not longer a fair comparison.
I walked to work for over a decade before I retired. I stopped at all the red lights and beat the cars most days. Bikes and pedestrians can go much faster than cars between lights when traffic is bad enough. Sure, there is favorable treatment (pedestrians get their own "roads" and bikes can drive between lanes), but there is no similar treatment that would make sense for cars because they are too big and insufficiently nimble.
If anything, bicycles are very rarely (in some places, never) favoured over cars in urban planning/design.
[deleted]
24 kilowatt•hours/day is better known as simply a kilowatt
No.
A kilowatt is the instantaneous consumption of 1,000 watts.
A kilowatt is the instantaneous consumption of 1,000 watts.
Saying a household averages a consumption of 1000 watts over the course of a day makes exactly as much sense as saying someone averaged 30mph over the course of a day on a road trip.
Eh GP is technically correct here if you do the dimensional analysis because the two time units cancel out and you're left with only a power unit.
If by "gearbox" you mean "Pulley" -- a setup such as this is probably most efficiently done by just putting a big (wide) pulley on the front crankshaft accessory belt and correct diameter pulley on the alternator, to get to whatever the target RPM of the alternator and whatever low RPM works under maximum load for the motor. Put the whole thing on a reinforce pallet and you're done.
This whole setup almost certainly isn't going to be able to supply "north america normal household power demand" volumes of power reliably for months at a time, but almost certainly do whatever a cheapo generator was doing before that cheapo's sketchy 150cc motor crapped out.
This whole setup almost certainly isn't going to be able to supply "north america normal household power demand" volumes of power reliably for months at a time, but almost certainly do whatever a cheapo generator was doing before that cheapo's sketchy 150cc motor crapped out.
By gearbox I mean anything to change from one RPM to another. Chains, belts, or gears are the obvious options. They all have pros and cons, but any would work. There are other options as well, but they tend to be a lot less efficient which destroys the whole point.
I’m very much not an engineer, but a below and pulley changing the ratio seems the most efficient.
> cooling system
Didn't watch the video yet, but under normal conditions the car is flying down the freeway so (I'm assuming) gets some cooling effect from that flow of air. But that's not happening in this case. Might be a problem.
Didn't watch the video yet, but under normal conditions the car is flying down the freeway so (I'm assuming) gets some cooling effect from that flow of air. But that's not happening in this case. Might be a problem.
Your car engine can typically deliver 150 horse power to the wheels, but after 6 seconds of that you are at freeway speeds and then your engine is only delivering about 25 horsepower. A cars cooling system is designed around that and the case where you need all 150 horsepower for 5 seconds, then drive for 30 seconds at 20 horse power before slamming on the brakes (6 horsepower to run the AC) for the next red light where you wait for 10 seconds (again 6 horse power for the AC).
Cooling from running down the freeway is easy to replace with a bigger fan. However the radiator itself is not large enough to get all the power the engine is capable of. (I also didn't watch the video, but I'm guessing the donor generator had a 12 horsepower engine so the radiator should be more than good enough). Of course there are other trade offs - many mechanics have a sign "speed costs money, how fast do you want to go", this sign isn't referring to the initial cost to tune the engine for max power, it is referring to max power means your engine needs a full rebuild every 20 hours of operation.
Cooling from running down the freeway is easy to replace with a bigger fan. However the radiator itself is not large enough to get all the power the engine is capable of. (I also didn't watch the video, but I'm guessing the donor generator had a 12 horsepower engine so the radiator should be more than good enough). Of course there are other trade offs - many mechanics have a sign "speed costs money, how fast do you want to go", this sign isn't referring to the initial cost to tune the engine for max power, it is referring to max power means your engine needs a full rebuild every 20 hours of operation.
This is a reasonable desperation setup for emergency power, but not a great off-grid solution.
Highway cruise for a compact car needs around 7 to 20HP, so a reasonable target output is in that range. That's 5 to 15 KWh. Seems small, but as others have pointed out, auto engines have peak outputs far beyond their continuous rating.
1800 RPM 60Hz generators are available, and larger generators tend to run at 1800 RPM. Or you could do something with belts or gears to keep the engine RPM down, as others pointed out. Running at low RPM is good if you want to run for a long time.
Probably a good idea to have the system disconnect output power until the frequency reaches at least 50 Hz, because this thing needs quite a while to reach operating frequency. Bringing up something like a refrigeration compressor (a likely emergency load) from 0 Hz to 60 Hz over the course of a minute may burn it out. Under-frequency operation is very bad for AC motors; they draw way too much current and overheat, because the inductance of the motor isn't able to oppose the lower frequency. Put an ohmmeter across an AC motor and note how low the DC resistance is.
Highway cruise for a compact car needs around 7 to 20HP, so a reasonable target output is in that range. That's 5 to 15 KWh. Seems small, but as others have pointed out, auto engines have peak outputs far beyond their continuous rating.
1800 RPM 60Hz generators are available, and larger generators tend to run at 1800 RPM. Or you could do something with belts or gears to keep the engine RPM down, as others pointed out. Running at low RPM is good if you want to run for a long time.
Probably a good idea to have the system disconnect output power until the frequency reaches at least 50 Hz, because this thing needs quite a while to reach operating frequency. Bringing up something like a refrigeration compressor (a likely emergency load) from 0 Hz to 60 Hz over the course of a minute may burn it out. Under-frequency operation is very bad for AC motors; they draw way too much current and overheat, because the inductance of the motor isn't able to oppose the lower frequency. Put an ohmmeter across an AC motor and note how low the DC resistance is.
> A cars cooling system is designed around that and the case where you need all 150 horsepower for 5 seconds, then drive for 30 seconds at 20 horse power before slamming on the brakes
My old 2004 Opel 1.6, 105hp could deliver almost full load (car fully packed with passengers and baggage, with roof trunk also packed, going 140km/h uphill with fully open throttle, fuel usage was reported as 16L/100km, typical road usage was 8L/100km) for about half an hour without any problems.
My old 2004 Opel 1.6, 105hp could deliver almost full load (car fully packed with passengers and baggage, with roof trunk also packed, going 140km/h uphill with fully open throttle, fuel usage was reported as 16L/100km, typical road usage was 8L/100km) for about half an hour without any problems.
In the end it’s all about the load not the horsepower. Doing the job of a 100hp engine with a 300hp engine doesn’t require 3x the cooling. So companies happily sell higher trim levels with more HP while keeping the same radiator.
Smaller engines are designed to operate at higher percentage of maximum capacity at lower speeds. Roll back to the days of 40hp engines and they max out highway speeds and can sustain that for hours. As you keep adding HP the maximum sustained load at a given speed doesn’t increase. So, 1000+ HP super cars can make use of that power at 200+ mph, but they don’t waste weight having radiators large enough to dissipate that heat continuously at 85mph because there’s no way the car is staying that slow while applying that much power.
External temperature also plays a role, cars need to be able to handle highway speeds at 45C adding headroom at lower temperatures. Trucks also need to be able to do that while towing a large load.
Smaller engines are designed to operate at higher percentage of maximum capacity at lower speeds. Roll back to the days of 40hp engines and they max out highway speeds and can sustain that for hours. As you keep adding HP the maximum sustained load at a given speed doesn’t increase. So, 1000+ HP super cars can make use of that power at 200+ mph, but they don’t waste weight having radiators large enough to dissipate that heat continuously at 85mph because there’s no way the car is staying that slow while applying that much power.
External temperature also plays a role, cars need to be able to handle highway speeds at 45C adding headroom at lower temperatures. Trucks also need to be able to do that while towing a large load.
25hp = 19kW or ~1x standard 42U rack, 105hp = 78kW or 20x typical households. Cars are powerful machines!
That’s the useful work which represents ~1/3 of the energy in gasoline. ICE cars needs to deal with ~2x that energy in waste heat.
A good rule of thumb is 1/3 of the energy into mechanical work, 1/3 into the cooling system, and 1/3 out the tailpipe. The actual numbers are pretty close to this across a wide range of operating conditions.
With the caveat that in cars the very long exhaust system dissipates a great of the heat rather than all of that energy literally coming out of the tailpipe as hot gas.
Also catalytic converters provide more complete combustion and thus generate even more heat.
Also catalytic converters provide more complete combustion and thus generate even more heat.
Well, heat your water with it.
In addition, I don't see why you wouldn't just buy a home battery pack and use that to store up energy. You can run the ice in the high power bursts to top off.
I just kind of like this post because there's going to be a lot of excess ICE engines out there once EVs take over the primary job of consumer transport.
Would be nice to have a DIY recipe to convert them over to leveling for your solar grid at home
In addition, I don't see why you wouldn't just buy a home battery pack and use that to store up energy. You can run the ice in the high power bursts to top off.
I just kind of like this post because there's going to be a lot of excess ICE engines out there once EVs take over the primary job of consumer transport.
Would be nice to have a DIY recipe to convert them over to leveling for your solar grid at home
IIUC the significant fractions of heat can't be absorbed, else it eats into efficiency, which is okay if part of the purpose of the engine is for heat - I think he's just pointing out the hydrocarbon-to-kinetic conversion ratio is around 1/3rd, which is a useful rule of thumb.
That seems a little bit nuts considering what they're doing with passive heat exchangers right now.
Waste heat from an ICE must be way more useful than a simple 10 or 20° gradient that they're trying to use for house heating and cooling
Waste heat from an ICE must be way more useful than a simple 10 or 20° gradient that they're trying to use for house heating and cooling
with 140km/h wind to cool it in addition to radiator fan
I don't think fan was engaged anyway, never noticed it working when moving, only when stationary. I don't think it would help anyway.
What I mean - cars can do fine for long periods under load as long as they are cooled appropriately, not only for 10s of full power.
What I mean - cars can do fine for long periods under load as long as they are cooled appropriately, not only for 10s of full power.
You look under the hood to see your fan moving while you're doing 140km/h? ;)
No, but I can hear it easily when car is idle, also see a change of power used by engine (fuel usage goes from 0.8L/h to 1.2L/h, not a small change). I purposefully wrote that I THINK that it doesn't work at speeds, because indeed it can be hard to notice it when going highway speeds. I would have to verify it probably with some CAN reader, but I think at speeds >40km/h it's not worth it to start the fan, air should be enough.
It wouldn't on highway, only time where extra cooling would be needed if you were on actual track where you'd have far higher average power on top of slower average speed.
>Your *American car engine can typically...
Agreed, only in America; and thank goodness for that.
I literally stopped at the Ford dealer today; there, I told the sales lady trying to sell me on the F150 that, for a few more thousand dollars, I prefer the F250 because I don't want a dinky euroboost 2.7 L turbo V6.
Luckily the F250 has a 6.8L V8 base.
I literally stopped at the Ford dealer today; there, I told the sales lady trying to sell me on the F150 that, for a few more thousand dollars, I prefer the F250 because I don't want a dinky euroboost 2.7 L turbo V6.
Luckily the F250 has a 6.8L V8 base.
For what?
Basically sounds like your typical American that buys a massive car truck. Just a drive around suburbia with for no real practical reason and F-250 would be ridiculous for that.
I'm glad every American male feels compelled by Ford and GM's advertising to buy 70 and $80,000 trucks because we'll be that much easier for them to budget out for EVs when they start coming out
Basically sounds like your typical American that buys a massive car truck. Just a drive around suburbia with for no real practical reason and F-250 would be ridiculous for that.
I'm glad every American male feels compelled by Ford and GM's advertising to buy 70 and $80,000 trucks because we'll be that much easier for them to budget out for EVs when they start coming out
Honestly? On the remotely unlikely event that I have an opportunity to switch on the high idle switch if some extinction folks block the road on the way back from soccer practice two miles away.
Opel basically does not exist in the US.
Opel was General Motor's European brand until 2017.
They sold very different cars in Europe than they did in the USA, but it was the same company.
They sold very different cars in Europe than they did in the USA, but it was the same company.
>A cars cooling system is designed around that and the case where you need all 150 horsepower for 5 seconds, then drive for 30 seconds at 20 horse power before slamming on the brakes (6 horsepower to run the AC) for the next red light where you wait for 10 seconds (again 6 horse power for the AC).
I'm no expert, but I can't imagine that this is true. I agree that is "average driving conditions", but there are plenty of times you're driving way outside of those conditions. That can't be how the cooling system is designed. I've never seen a car even tick up in temperature, under all kinds of tom foolery.
I'm no expert, but I can't imagine that this is true. I agree that is "average driving conditions", but there are plenty of times you're driving way outside of those conditions. That can't be how the cooling system is designed. I've never seen a car even tick up in temperature, under all kinds of tom foolery.
The limiting factor in average horsepower output over time is definitely the cooling system on most cars. It's just that most people don't run their car at 80% of rated output for extended periods, otherwise you would absolutely overheat it.
I've towed large loads up extended grades (hello shasta and grapevine) and you absolutely will overheat on a hot day. And that's with an uprated towing rig that had a radiator sized for the job - imagine that same horsepower of engine in a passenger car with 1/3rd the radiator surface area.
I've towed large loads up extended grades (hello shasta and grapevine) and you absolutely will overheat on a hot day. And that's with an uprated towing rig that had a radiator sized for the job - imagine that same horsepower of engine in a passenger car with 1/3rd the radiator surface area.
Subaru engines are sometimes used in DIY small airplanes and they work well without overheating.
This, it can be done.
This, it can be done.
The airflow differences between airplanes and cars are pretty significant, much higher near ground level and much lower at altitude, so they're kind of a different beast than a static generation setup.
Yeah but they're basically always derated.
Amusingly, this is also true for modern laptops.
Makes me wonder what a "portable desktop with integrated screen and input" like I had in 2004 would be like these days. I think it was 16 pounds? with a pentium 3 desktop processor in it and about 4 screaming fans. Loved that thing.
Depending on your route, there's some big mountains leaving Los Angeles, if you've got a lot of stuff in your car, it's pretty easy to get the engine and transmission warmer than usual. Engine heat isn't too hard to manage if it's just for a little while --- roll down the windows, turn the fan to high and the heater to max. May be unconfortable, but better than overheating.
Afaik, that won't help your transmission though. If you run that at high loads often, you'll want enhanced cooling for that; often part of a factory tow package, but often available from the aftermarket as well.
Afaik, that won't help your transmission though. If you run that at high loads often, you'll want enhanced cooling for that; often part of a factory tow package, but often available from the aftermarket as well.
I don't recall seeing an automatic transmission in a car or truck that doesn't have a transmission fluid cooler in front of the radiator for the 25 years I've been paying attention.
You can instal a transmission cooler if you live in that region.
> max power means your engine needs a full rebuild every 20 hours of operation
Top fuel drag racers need a rebuild after every run, which typically lasts 4-5 seconds. Their engines can produce 10,000 HP, which is about 7.5 MW.
https://en.wikipedia.org/wiki/Top_Fuel
Top fuel drag racers need a rebuild after every run, which typically lasts 4-5 seconds. Their engines can produce 10,000 HP, which is about 7.5 MW.
https://en.wikipedia.org/wiki/Top_Fuel
And other race cars get the best of both worlds.
Le Mans cars and other touring cars are famous for holding up 24hrs under very high loads, even with the engine strung out beyond its street legal spec, but I think the most impressive feat is the Baja 1000.
Modern trophy trucks make ~1000 horspower, and the load is insane. The engines are running a pretty high average throttle, at high RPM, pushing a giant, heavy truck through sand, in a blazing hot desert. The fine dust can clog the filter, radiators, and get in all sorts of crevices. The whole drivetrain is constantly being shocked as the wheels leave the ground then jolt back to the correct RPM when the truck lands. And the whole truck is constantly being G-shocked, crashing into terrain you wouldn't even want to hike over at highway speeds, over and over again, for 1000 miles.
This was impressive back when the trucks were making a mere 300-600 horsepower, but honestly I have no idea how the modern turbocharged monsters even hold up.
Le Mans cars and other touring cars are famous for holding up 24hrs under very high loads, even with the engine strung out beyond its street legal spec, but I think the most impressive feat is the Baja 1000.
Modern trophy trucks make ~1000 horspower, and the load is insane. The engines are running a pretty high average throttle, at high RPM, pushing a giant, heavy truck through sand, in a blazing hot desert. The fine dust can clog the filter, radiators, and get in all sorts of crevices. The whole drivetrain is constantly being shocked as the wheels leave the ground then jolt back to the correct RPM when the truck lands. And the whole truck is constantly being G-shocked, crashing into terrain you wouldn't even want to hike over at highway speeds, over and over again, for 1000 miles.
This was impressive back when the trucks were making a mere 300-600 horsepower, but honestly I have no idea how the modern turbocharged monsters even hold up.
Also, the engine throttle is open for a long time on the flat, barren stretches.
That seems minor, but there are no paved racing leagues where a 1000hp+ engine can run flat-out for a long time. Le Man's formerly 6 km straight was the extreme, and they eventually shortened that with chicanes.
That seems minor, but there are no paved racing leagues where a 1000hp+ engine can run flat-out for a long time. Le Man's formerly 6 km straight was the extreme, and they eventually shortened that with chicanes.
Not 1000HP, but Nascar several years back was running something near 800HP, and at a couple tracks (Daytona and Talladega) they were wide open the whole way around if they were in front. Those races last several hours, with some number of short breaks due to cautions.
Yeah, NASCAR engineering is underappreciated too, but I didn't know they could do a lap with an open throttle around Talladega. That's crazy.
Fun fact: the Porsche 917 still holds the lap record at Talladega, even though it was set in 1975, because no one else is crazy enough to run a 1200HP 1700lb car around it. And it got so hot (running an open throttle?) that it spontaneously caught on fire when it stopped in the pits without any airflow.
Fun fact: the Porsche 917 still holds the lap record at Talladega, even though it was set in 1975, because no one else is crazy enough to run a 1200HP 1700lb car around it. And it got so hot (running an open throttle?) that it spontaneously caught on fire when it stopped in the pits without any airflow.
Baja 1000 trucks are amazingly light compared to street trucks.
Like 5,100lb?
https://www.jimcoracing.com/pages/fastball-racing-spec-troph...
I dunno if that counts the spares, the fuel cell and such, but thats in the ballpark of an F150.
https://www.jimcoracing.com/pages/fastball-racing-spec-troph...
I dunno if that counts the spares, the fuel cell and such, but thats in the ballpark of an F150.
Depends on… well, everything, but towing a 1-tonne trailer up a long hill is far more taxing on a car’s cooling system than this. I’d expect any decent car to be designed to handle continuous running at peak torque, if not peak power.
(Why peak torque? Because that’s peak efficiency, for petrol engines at least. Makes sense if you think about it.)
(Why peak torque? Because that’s peak efficiency, for petrol engines at least. Makes sense if you think about it.)
Cars are not built to run at peak torque for long as nobody does that. Cars are design for maximum power for long enough to get up to speed, and which makes for a lot more power at peak torque than they need for running at highway speeds.
Sometimes a truck will be designed to run near peak torque while towing uphill on a hot day (AC) with a headwind, but when you do that it takes a long time to accelerate to highway speed and so truckers typically just buy more peak power (trucks are already notorious for slow acceleration). Running at less that peak torque isn't too much a loss (and diesel engines don't suffer nearly as much from running at less than peak torque so the savings doesn't add up very fast for trucks)
Sometimes a truck will be designed to run near peak torque while towing uphill on a hot day (AC) with a headwind, but when you do that it takes a long time to accelerate to highway speed and so truckers typically just buy more peak power (trucks are already notorious for slow acceleration). Running at less that peak torque isn't too much a loss (and diesel engines don't suffer nearly as much from running at less than peak torque so the savings doesn't add up very fast for trucks)
This actually sounds like quite the argument for electric trucks.
If only batteries were not so heavy. Trucks need a lot of power when towing a large load.
Trains can use overhead wires, but running that on roads is tricky when people expect to pass.
Trains can use overhead wires, but running that on roads is tricky when people expect to pass.
[deleted]
"Your car engine can typically deliver 150 horse power to the wheels, but after 6 seconds of that you are at freeway speeds and then your engine is only delivering about 25 horsepower."
Unless you're in Colorado doing 80 mph, uphill for ten miles, fully loaded with cargo - then you engine brake (ie dissipate your KE into the engine block) on the way down. Or you take you car to the track. In both situations your cooling system is still expected to deliver, and does, since its not that big an issue to size it properly and a massive reliability issue if it isn't.
Unless you're in Colorado doing 80 mph, uphill for ten miles, fully loaded with cargo - then you engine brake (ie dissipate your KE into the engine block) on the way down. Or you take you car to the track. In both situations your cooling system is still expected to deliver, and does, since its not that big an issue to size it properly and a massive reliability issue if it isn't.
25hp is probably enough to power your household (18kW or 170A at 110V). It's certainly well over the mean summer usage, but peak usage is probably higher in hot climates (I couldn't find any typical peak usage numbers).
Peak potential usage is way higher than peak convenient usage after a couple of trivial optimisations. Just “don’t run the dryer, the kettle and the toaster at the same time” will knock 4-5kW off the max. Schedule your hot water system to only run off peak and that’s another 2.4-3.6kW.
Most houses in Italy are only getting 3 kW, +10% of tolerance for a few hours, and if people can increase the maximum power they can draw, it is still very uncommon.
25 HP would be enough to power a small apartment building.
25 HP would be enough to power a small apartment building.
In many European houses the main power line into the house has a 35A fuse at 230V, so that's only 8kW maximum load.
Heating (and water) comes from natural gas, or a high efficiency electric heatpump.
Heating (and water) comes from natural gas, or a high efficiency electric heatpump.
In the US I've seen one house with 30amps at 240V (I also heard about a house from that era getting 30 amps at 120 volts), and it was from the 1930s with no updates. Even in the 1950s houses were getting 60 amps at 240V - which allowed for an electric stove to draw 40 amps 240V, and have enough for the rest of the house. These days small houses get 100amps, while large ones get at least 200. Very large houses sometimes get 400 amps. If you install geothermo you get 300 amps because even though geothermo is highly efficient in the worst case it can draw 80 amps at 240 volts (you only see those worst cases when doing the max power test at install time).
Unless it is a tiny house I wouldn't not expect 35amps to be enough to run a heat pump any everything else in a house (at least none of the houses I've seen in Europe, though I've only been there for a few weeks total so there is much I have not seen). Large RVs in the US get 50 amps at 240volts, while small ones get 30 amps at 120 volts - both compare to a tiny house in size.
Unless it is a tiny house I wouldn't not expect 35amps to be enough to run a heat pump any everything else in a house (at least none of the houses I've seen in Europe, though I've only been there for a few weeks total so there is much I have not seen). Large RVs in the US get 50 amps at 240volts, while small ones get 30 amps at 120 volts - both compare to a tiny house in size.
There are millions of houses like that over here. An 8 kW heatpump is enough to heat the house, and with the high COP that would electrically only be a 2 to 3 kW load.
A car alternator is typically 2kW-3kW at most, and is very roughly 50% mechanically efficient, so it uses 4-6kW of mechanical power. Ie: 1/18th of the 150hp (111kw) engine's capacity...about 5%.
Cars are already designed to run A/C and alternator almost continuously, and the AC not only generates load, it pumps a lot of heat into the air coming through the radiator because the condenser is in front of the radiator. They're designed (if the manufacturer did their environmental testing properly) to do that even in ~110+ degree weather.
Methinks you should stick to things you know something about.
PS: Many cars, even regular passenger cars - can handle being driven around a track, where you can go through a full tank in under an hour's worth of driving, and are either on the gas or braking during most of the session.
There are also things called hills and mountains, which may take minutes to climb, or more. Plenty of cars make it up the Mt. Washington auto road (where the challenge is making it back down without overheating one's brakes; engine braking must be used.)
There's something called "towing", which lots of people do the world around with minivans and passenger cars (not just pickups and SUVs.)
Cars are already designed to run A/C and alternator almost continuously, and the AC not only generates load, it pumps a lot of heat into the air coming through the radiator because the condenser is in front of the radiator. They're designed (if the manufacturer did their environmental testing properly) to do that even in ~110+ degree weather.
Methinks you should stick to things you know something about.
PS: Many cars, even regular passenger cars - can handle being driven around a track, where you can go through a full tank in under an hour's worth of driving, and are either on the gas or braking during most of the session.
There are also things called hills and mountains, which may take minutes to climb, or more. Plenty of cars make it up the Mt. Washington auto road (where the challenge is making it back down without overheating one's brakes; engine braking must be used.)
There's something called "towing", which lots of people do the world around with minivans and passenger cars (not just pickups and SUVs.)
This is an interesting and informative comment, but it would have been much better without the condescending snarky tone.
Even on the track you get some cooling time while on the brakes. And cars do overheat on the track if the driver is not careful. You are correct though that cars are designed for up a mountain on a hot day with the AC on - which uses more than 25 horsepower - but that is still less than max power. That leaves a lot of headroom for racing on a level track, but you do need to watch the temp gauge (or update the cooling system is done on the track if the race rules allow)
Even 25 hp is large compared to the generator output shown (about 5 kW or about 7 hp).
I learn so much on HN.
I'd bet this car engine will be lightly loaded since it's many times bigger than the engine in a generator.
From what I was able to dig up[1][2], the generator (that the alternator came out of) has a 1-cylinder, 4-stroke, air-cooled, 305cc engine.
A Toyota Sienna minivan's[3] engine is around 3L, so it's basically 10 times as big.
---
[1] generator product listing: https://www.lowes.com/pd/Troy-Bilt-5-500-Running-Watts-Porta...
[2] similar engine: https://www.briggsandstratton.com/na/en_us/product-catalog/e...
[3] https://en.wikipedia.org/wiki/Toyota_Sienna
From what I was able to dig up[1][2], the generator (that the alternator came out of) has a 1-cylinder, 4-stroke, air-cooled, 305cc engine.
A Toyota Sienna minivan's[3] engine is around 3L, so it's basically 10 times as big.
---
[1] generator product listing: https://www.lowes.com/pd/Troy-Bilt-5-500-Running-Watts-Porta...
[2] similar engine: https://www.briggsandstratton.com/na/en_us/product-catalog/e...
[3] https://en.wikipedia.org/wiki/Toyota_Sienna
In this case the generator is drawing off 5.5kw of power, if it is maxed out.
This engine is capable of around 150kw of power, and the cooling system is capable of keeping up with that at highway speeds.
My guess is that if they are using the standard cooling system, it isn't even close to being taxed with a 5.5kw load even at 3600 RPM. That's less power output than you would expect while running the ac in stop and go traffic.
This engine is capable of around 150kw of power, and the cooling system is capable of keeping up with that at highway speeds.
My guess is that if they are using the standard cooling system, it isn't even close to being taxed with a 5.5kw load even at 3600 RPM. That's less power output than you would expect while running the ac in stop and go traffic.
Most cars are cooled by a fan these days, and many use an electric fan that can vary speed to keep the engine cool.
Best efficiency would be to use the fact you’re not moving to have more radiator surface area available but it’s probably not worth it.
Best efficiency would be to use the fact you’re not moving to have more radiator surface area available but it’s probably not worth it.
The fan in cars is typically not enough to keep it cool while stationary under load, but in typical home applications you won't have that big load anyway. Big load for a car is >10kW. You can also pretty cheaply get a bigger external fan, like those used on dynamometers.
One nice side effect of using car as generator - free heat in winter if you extend cooling loop to your home.
One nice side effect of using car as generator - free heat in winter if you extend cooling loop to your home.
> Big load for a car is >10kW
I don't have any idea if it's relevant at all (or how much the number can be trusted), but when I floor the accelerator in my Bolt, the dash indicator says it's using about 120kW.
I don't have any idea if it's relevant at all (or how much the number can be trusted), but when I floor the accelerator in my Bolt, the dash indicator says it's using about 120kW.
How is a stationary car engine under load? Oh right, like my asshat neighbor that likes to sit in the driveway a 6AM revving his engine every. single. morning.
The fans cars have are not sufficient to cool the engine at high load.
You could do few things to mitigate this issue.
1. install larger fans on to the radiator.
2. use a big shop fan to blow air over the radiator.
3. remove the mechanical thermostat on the engine, so that it takes longer to get to operating temperature.
1. install larger fans on to the radiator.
2. use a big shop fan to blow air over the radiator.
3. remove the mechanical thermostat on the engine, so that it takes longer to get to operating temperature.
> 3. remove the mechanical thermostat on the engine, so that it takes longer to get to operating temperature.
Modern engines are designed to work at preferred temperature. They have two cooling loops, one small which is constantly cooling cylinders and one big (with radiator) which cools the small one to keep engine at proper temperature, not too high and not too low, by mixing some of small loop coolant with large loop coolant.
Point 2 is the best solution.
Modern engines are designed to work at preferred temperature. They have two cooling loops, one small which is constantly cooling cylinders and one big (with radiator) which cools the small one to keep engine at proper temperature, not too high and not too low, by mixing some of small loop coolant with large loop coolant.
Point 2 is the best solution.
Install a larger radiator is the correct fix if this is a concern. While the stock fan is not the most airflow, if it isn't enough you want the bigger radiator.
It gets most of its cooling from the air flow. Cover up all openings if your car and you will overheat the engine very quickly. If you put a car on a dyno you usually put a big fan in front of the car to provide cooling.
As another poster has pointed out, the power output is very small compared to the engine's capacity. So cooling is not really a problem. From the engine's point of view it's pretty close to idle, and the car's fan should have no problem pulling enough airflow.
Car gearboxes are a spectacular cause of power loss (in the order of 20% IIRC), so probably better to come up with a simple gear reduction or a belt-driven pulley system.
They didn't say use the car's transmission. The suggestion of a 2:1 gear reduction could easily be a simple gear reduction or a belt-driven pulley. You've tried to inject something on your own accord for possibly a misunderstanding??
I read "gearbox" as, well, an automotive gearbox, which would hardly be surprising in the context of the article.
2:1 could easily mean crank the gearbox into a gear that approximately produces that ratio.
> You've tried to inject something on your own accord for possibly a misunderstanding??
WTH is that supposed to mean? If I misunderstood anything it was a honest mistake. GP suggested a RPM reduction for fuel efficiency reasons, it would be counterproductive to offset that efficiency gain with a high-loss mechanical device. There was neither ill intent nor hidden agenda.
2:1 could easily mean crank the gearbox into a gear that approximately produces that ratio.
> You've tried to inject something on your own accord for possibly a misunderstanding??
WTH is that supposed to mean? If I misunderstood anything it was a honest mistake. GP suggested a RPM reduction for fuel efficiency reasons, it would be counterproductive to offset that efficiency gain with a high-loss mechanical device. There was neither ill intent nor hidden agenda.
Yeah, they didn't mention many specifics; I also imagine that they're just pulling the power off the engine using the accessory belt connected to their existing alternator -> inverter setup.
Similarly -- the concerns about how to cool the device if it s putting down 100hp -- that's 74570 watts; it's unlikely they're using a harbor freight generator's alternator to generate that kind of power.
Similarly -- the concerns about how to cool the device if it s putting down 100hp -- that's 74570 watts; it's unlikely they're using a harbor freight generator's alternator to generate that kind of power.
Some car gearboxes are that bad. However others are much lower. Are we talking about a "slushbox" automatic without a locking torque converter, or an all gear manual transmission - there is a big difference.
I didn't specify what type of gear box because there are many different options. Belts of the front pulleys would work. You could rig up a chain drive system as well. there are pros and cons to each.
I didn't specify what type of gear box because there are many different options. Belts of the front pulleys would work. You could rig up a chain drive system as well. there are pros and cons to each.
> Are we talking about a "slushbox" automatic without a locking torque converter, or an all gear manual transmission - there is a big difference.
Correct. IIRC again (numbers from 2010ish, probably there were some improvements since but I bet physics limit those) the best stick were 15%-20%; slushboxes were 25%-30%.
Such loss is justified by making the car able to operate on a much wider range, from standstill to highway speeds, and solve the ~zero torque at <1000rpm problem. IOW without a gearbox the car is useless.
Without that requirement a simple reduction would be much more efficient.
One of the huge benefits of going electric is that - in addition of having stellar electric to mechanical energy conversion efficiency (90-95%, vs a very lousy number I can't recall for chemical to mechanic energy) - the engine can basically be put on direct drive because torque is immediately available starting at 0rpm and all the way to max rpm, so no additional loss.
> I didn't specify what type of gear box because there are many different options. Belts of the front pulleys would work. You could rig up a chain drive system as well. there are pros and cons to each.
Totally fair! I didn't want to sound dismissing, only complementary.
Correct. IIRC again (numbers from 2010ish, probably there were some improvements since but I bet physics limit those) the best stick were 15%-20%; slushboxes were 25%-30%.
Such loss is justified by making the car able to operate on a much wider range, from standstill to highway speeds, and solve the ~zero torque at <1000rpm problem. IOW without a gearbox the car is useless.
Without that requirement a simple reduction would be much more efficient.
One of the huge benefits of going electric is that - in addition of having stellar electric to mechanical energy conversion efficiency (90-95%, vs a very lousy number I can't recall for chemical to mechanic energy) - the engine can basically be put on direct drive because torque is immediately available starting at 0rpm and all the way to max rpm, so no additional loss.
> I didn't specify what type of gear box because there are many different options. Belts of the front pulleys would work. You could rig up a chain drive system as well. there are pros and cons to each.
Totally fair! I didn't want to sound dismissing, only complementary.
I'm curious what the loss for a typical constant-mesh manual gearbox would be. I assumed 90% or more efficiency.
What about them makes them so inefficient?
Automotive gearboxes prime goal is to:
a) expand the workable range of the IC engine (1000-5000rpm for Diesel, 1000-9000 - at best - for NA petrol, turbocharging dials it down)
b) solve the zero-to-low rpm problem that causes stalling due to nonexistent torque
It results in a complex device where many parts are still spinning even on the non-engaged gear. Look at a cut out of a manual transmission. The irony is that an epicyclic automatic transmission is mechanically efficient, up to the torque converter which uses fluid coupling.
Efficiency is a secondary goal to the ones above, without which the car would be useless.
a) expand the workable range of the IC engine (1000-5000rpm for Diesel, 1000-9000 - at best - for NA petrol, turbocharging dials it down)
b) solve the zero-to-low rpm problem that causes stalling due to nonexistent torque
It results in a complex device where many parts are still spinning even on the non-engaged gear. Look at a cut out of a manual transmission. The irony is that an epicyclic automatic transmission is mechanically efficient, up to the torque converter which uses fluid coupling.
Efficiency is a secondary goal to the ones above, without which the car would be useless.
If the torque converter doesn't have a lock that is a big loss. Those same transmissions also tend to have low efficiency hydraulic pumps internally to select the gears. Modern automatic transmissions tend to be much better than older ones.
> Modern automatic transmissions tend to be much better than older ones.
I seem to recall improvements in that area around 2015 (probably driven by emissions regulations) but don't know the implementation details. One change was also a marked increase in available ratios (7, up to 10) which combined with better logic drives mpg down overall, sometimes lower than stick or dual clutch on standardised tests.
I seem to recall improvements in that area around 2015 (probably driven by emissions regulations) but don't know the implementation details. One change was also a marked increase in available ratios (7, up to 10) which combined with better logic drives mpg down overall, sometimes lower than stick or dual clutch on standardised tests.
This is awesome. I lived on a sailboat for a while and sometimes you get cloudy weather for days, blocking your ability to use solar to top up your batteries. The small M35 universal diesel engine I had had one thing going for it, it had a lot of torque. Torque I use to turn a 110V 120A alternator. The alternator (like a car’s) charges the battery, except in my case it was charging a lot of battery. 6 12V 200AH Lithium Iron batteries. These batteries ran all the “home” appliances for several days before needing a recharge. 120V 3000W inverter, A/C, Fridge, coffee maker, water maker, electric stovetop, lights, navigation, radio, Starlink, Xbox.
If having a vehicle is unsightly, you can remove the engine onto a stand and wire it up exactly as described in this video. The only thing you’d need to run an engine is a fuel line, a spark, and compression.
If having a vehicle is unsightly, you can remove the engine onto a stand and wire it up exactly as described in this video. The only thing you’d need to run an engine is a fuel line, a spark, and compression.
You also need a cooling system to run nearly all engines. Generally a car engine doesn't have enough cooling system to run at max power for very long (it is only a few seconds between the light turning green and you being at speed, then you need much less power). Your sailboat as the nearly infinite ocean to cool itself with.
Most likely your engine also needs a computer, which implies an electrical system.
Most likely your engine also needs a computer, which implies an electrical system.
> Most likely your engine also needs a computer, which implies an electrical system.
Old diesel clunkers not really, at least if you don't care about emissions control. Fuel injection / exhaust valve control is purely mechanical, all they need electricity for is the engine starter and, depending on age, the cooling fan.
Modern engines, on the other hand, these can be really hard to run on their own outside of a car, at least from hearsay - I only have had experience with an 1994 VW T4 van.
Old diesel clunkers not really, at least if you don't care about emissions control. Fuel injection / exhaust valve control is purely mechanical, all they need electricity for is the engine starter and, depending on age, the cooling fan.
Modern engines, on the other hand, these can be really hard to run on their own outside of a car, at least from hearsay - I only have had experience with an 1994 VW T4 van.
>all they need electricity for is the engine starter and, depending on age, the cooling fan.
If you get an old enough diesel engine or can do the mod yourself you don't even need an electric starter. The first diesel engine I worked on used a gasoline engine as a "pony motor" to spin the diesel engine flywheel enough to generate the compression needed to start the diesel engine. From memory (probably wrong haha) you cranked the gasoline engine and brought it up to high rpm and then you started the diesel engine using a lever that gradually engaged the diesel engine flywheel bringing it up to operating speed. Once the diesel engine was running you backed off the lever and killed the gasoline engine.
An obvious disadvantage would be the necessity to maintain stocks of two fuel types. Other than that it is a near fool-proof way to handle cranking a diesel engine. The electric starter is replaced by the gasoline engine and flywheel linkage. You effectively roll-start the diesel using the gasoline engine.
If you get an old enough diesel engine or can do the mod yourself you don't even need an electric starter. The first diesel engine I worked on used a gasoline engine as a "pony motor" to spin the diesel engine flywheel enough to generate the compression needed to start the diesel engine. From memory (probably wrong haha) you cranked the gasoline engine and brought it up to high rpm and then you started the diesel engine using a lever that gradually engaged the diesel engine flywheel bringing it up to operating speed. Once the diesel engine was running you backed off the lever and killed the gasoline engine.
An obvious disadvantage would be the necessity to maintain stocks of two fuel types. Other than that it is a near fool-proof way to handle cranking a diesel engine. The electric starter is replaced by the gasoline engine and flywheel linkage. You effectively roll-start the diesel using the gasoline engine.
> An obvious disadvantage would be the necessity to maintain stocks of two fuel types.
Wouldn’t a starter motor running off a battery charged by the very generator you are running just be an all around better solution? You can run some modern starter motors off a tiny 12x8 in AGM.
Wouldn’t a starter motor running off a battery charged by the very generator you are running just be an all around better solution? You can run some modern starter motors off a tiny 12x8 in AGM.
That may be true if you are building this today. There evidently were enough problems with that setup back when these pony motors were common to make the use of a pony motor instead of battery power more practical. Perhaps it was a battery efficiency issue or one where a battery couldn't supply enough amperage to generate the torque required for a standard starter to cause the diesel engine to start and run. I know that a pony motor starter was standard on old heavy equipment diesel engines until the late 1940's and possibly after that.
That’s true and there certainly other considerations. I know which I’d consider to be a more solid/reliable option if I were going to be somewhere without access to electricity, at least. It’s easy to see when you’re running low on gasoline and when you’ll need to top off, but I wouldn’t want to be relying on a small 12v battery if I didn’t have a backup jump source available.
That's true. For backup power on my own property I bought a used towable light tower/generator with an industrial Caterpilalr diesel engine and a 20 kW generator. It is portable, comes with its own lights, has a large capacity fuel tank so it can run for days, and it generates enough power to power my house and my shop should I lose grid power. Since it is portable I don't need to rebuild my old gasoline welder to use working on my fence since I can power my electric welder directly from the unit. It also has enough outlets to run several electric tools simultaneously.
I have to add a frequency meter on the generator so that I can make sure I get some clean power and a power conditioner to smooth all the wrinkles so my electronics inside the house won't be damaged. Then I need to have an electrician add the subpanel and manual or automatic power transfer switch but for the price I paid it is a bargain over the usual generator packages available.
I have to add a frequency meter on the generator so that I can make sure I get some clean power and a power conditioner to smooth all the wrinkles so my electronics inside the house won't be damaged. Then I need to have an electrician add the subpanel and manual or automatic power transfer switch but for the price I paid it is a bargain over the usual generator packages available.
That sounds like the making of a great setup! I likewise far prefer to purchase used industrial equipment instead of new residential-grade stuff. But as much as I’d love to be in your kind of environment, we’re in a more suburban setting at least for the medium term - where I’m blessed to have piped natural gas, though. I haven’t bit the bullet yet, but the convenience of a NG generator in that setting is hard to compete with.
I promise I would already have a NG generator if I had gas to the property. I have a high pressure pipeline easement across my place now but there is no way to tie in or buy a drop to supply anything here. It is a gathering system and not distribution I guess. Propane is doable but we decided to focus on solar for those things that aren't easily tied to the existing grid power and this portable generator for its high utility value out here. Good luck to you!
Video of this in action:
https://youtu.be/AL0ls_UpT8w?t=361
The whole video is worth a watch, but I linked directly to the timestamp where he begins to explain how the engines are started with a petrol starter. To power a foghorn. Amazing stuff.
https://youtu.be/AL0ls_UpT8w?t=361
The whole video is worth a watch, but I linked directly to the timestamp where he begins to explain how the engines are started with a petrol starter. To power a foghorn. Amazing stuff.
Yeah that is amazing and it is just like the engines we had on those post-WWII bulldozers and maintainers. Fire up the gasoline engine and get it screaming at high rpm and then use that high rpm to transfer power to the flywheel of the diesel engine which will crank and run once the compression is high enough to ignite the diesel.
Here is a video of a guy cranking a Caterpillar D2 like we had to crank our D4 back in the day. [0]
When I started working with that small family-owned company I had no real experience with mechanical things other than my own pickup truck. When I finally moved on from them a couple years later I could maintain, tear down, and rebuild gasoline and diesel engines, compressors, hydraulics, air brakes, etc. We did all of that ourselves in addition to the real jobs of pipeline maintenance and repair and oil spill cleanup. I don't remember all the times I spent laying on the dirt floor of the "shop" there in central Texas and cursing all the oily sand and crap that fell in our eyes and faces as we tried to fix things after the day's work was done. Luckily beer-thirty was a cherished event that came with hang-down (summer sausage), cheddar cheese chunks, fresh onion slices, cold milk and saltine crackers. We finished most days in the domino shack trying to avenge the previous days' losses. Good times indeed.
[0]https://www.youtube.com/watch?v=Ck210eL9qcI
Here is a video of a guy cranking a Caterpillar D2 like we had to crank our D4 back in the day. [0]
When I started working with that small family-owned company I had no real experience with mechanical things other than my own pickup truck. When I finally moved on from them a couple years later I could maintain, tear down, and rebuild gasoline and diesel engines, compressors, hydraulics, air brakes, etc. We did all of that ourselves in addition to the real jobs of pipeline maintenance and repair and oil spill cleanup. I don't remember all the times I spent laying on the dirt floor of the "shop" there in central Texas and cursing all the oily sand and crap that fell in our eyes and faces as we tried to fix things after the day's work was done. Luckily beer-thirty was a cherished event that came with hang-down (summer sausage), cheddar cheese chunks, fresh onion slices, cold milk and saltine crackers. We finished most days in the domino shack trying to avenge the previous days' losses. Good times indeed.
[0]https://www.youtube.com/watch?v=Ck210eL9qcI
I've tried with Opel from 2004. I had a very modern version (with everything over CAN, even gas pedal) and I had to disconnect A LOT of sensors in order for it to no longer start (don't ask why). Modern diesel cars are a little worse for this, because of all the emissions regulations requiring adblue and dpf filters to work correctly. If you run out of adblue in some cars, you have to get it towed to dealer for checkup and reset.
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I think everyone here is underestimating power density of a car engine. GP's alternator is 110V/120A, that's 13.2kW, or up to 8-way tea kettle boiling or Xeon workstation use simultaneously(1.5kW each).
Chances are you won't be running 4 YouTuber editing machines, 2 pots cooking on IH stoves, 2 air conditioners and a USB-PD laptop charger all drawing full amount inside the living quarter on a sailboat. That's before counting in 6x 12V/200Ah = 14.4kWh battery system which safely doubles, possibly quadruple instantaneous draw.
Chances are you won't be running 4 YouTuber editing machines, 2 pots cooking on IH stoves, 2 air conditioners and a USB-PD laptop charger all drawing full amount inside the living quarter on a sailboat. That's before counting in 6x 12V/200Ah = 14.4kWh battery system which safely doubles, possibly quadruple instantaneous draw.
Most household requirements are about 13kW. So not much different than your suburban bungalow needs.
I think there's something wrong with your palace if you're maxing out 100A breakers, that's 720[hr] x 13[kWh] x 0.30[$/kWh] = $2.8k/month. Even if you meant 1/3 duty it's $936/month.
Average household usage in US is 20-40kWh/day... not sure where does 13kW figure fits in that picture.
Average household usage in US is 20-40kWh/day... not sure where does 13kW figure fits in that picture.
they missed a decimal point. Average US household consumption over a year is approx 1.25KW.
200A service is standard transformer to a house.
Constant 50% utilization is not!
We both understand that the service has to support the max load, right? The average is less than worthless for calculating capacity of circuit breakers etc.
Living on a sailboat, the cool water would not be a problem. Just some filters to avoid clogging the cooling ducts.
Wouldn't it make more sense to install 230V on a boat? Modern electronics handle 100-240 anyway and you can save on cables.
12VDC is the standard on boats, campervans, RVs, etc because it can be delivered straight from the batteries. In order to deliver 240/120VAC you'd need an inverter to generate the signal, and this obviously introduces loss during conversion. For cable runs through the length of my boat (52ft), the cables aren't particularly thick - the thickest cables are in the engine bay, going from the alternator on the diesel engine to the batts, and again from the Solar controller (MPPT) to the batts.
There's a plethora of stuff you can use with 12VDC to the extent that the only things I run off 240VAC is the vacuum cleaner and the TV (12VDC TVs are available but the cost vs quality payoff isn't really worth it).
There's a plethora of stuff you can use with 12VDC to the extent that the only things I run off 240VAC is the vacuum cleaner and the TV (12VDC TVs are available but the cost vs quality payoff isn't really worth it).
230VAC flat screen TVs tend to be powered by 14VDC at the motherboard level, might well function if fed 12VDC from an external power source, bypassing the built-in step-down converter entirely.
Typically you don't want lethal potential in such wet environments. Ever wondered why emergency lights on ferries are different than the standard ones? Also, you don't want any earth breaker since you really want the lights, pump and motor to be working no matter how much water you have on the wrong side of the hull.
I would think 110v would be a little bit safer in the wet environment. Not perfectly safe but better.
Boats are typically so small that you can use smaller cables without problem even at 120 volts. Many of them run only 12 volts (often most things like lights and radios are run on 12 volts, but the owner as an inverter for a couple appliances they can't find in 12 volt). Of course nobody runs smaller cables at 120 volts because you would need an engineer to figure out the proper rating - it is cheaper to just use the standard code wires. If you do pay an engineer you will probably discover on boats you need to use the larger wires anyway for mechanical reasons.
Having wired up a couple travel trailers and a boat (and, incidentally, being an EE who can theoretically run those calcs), I agree with the parent: It would be better if the industry switched to 120V/220V AC for more parts, and away from 12V.
The problem is that the ampacity in a 12V DC light circuit is 10x that of an equivalent-power 120V AC system. And worse yet, power dissipation in a resistive element is equal to I^2 R, so you're heating the wiring harness with power losses are 100x worse than in a 120V system and almost 200x worse than a 220V system. So you have to oversize the wires to reduce R, which adds weight and cost. And if you drop 2V to line losses in your 12V system, your device is seeing 83% of the nominal voltage, while if you drop 2V in a 120V system (you won't, because Ohm says voltage drop is equal to IR, and I is 1/10th that of a 12V system), but still, you're 98% nominal.
They're running 12V because that's the voltage of a classic 6-cell lead-acid battery, and you probably didn't want 220V in your Model T, even with felted asbestos insulation, but I'd be confident enough to lick a modern XLPE wire carrying 220V. A century of using those lead acid batteries (and worse, 3-cell 6V systems...can't endorse converting your classic car to 12V enough...) created now-entrenched economies of scale for lamps, and switches, and pumps, and radios, and fans, and most of the other things you need in a boat or camper. The only advantage of using those 12V parts is that their manufacturers put a little more effort into making them efficient. No one (sadly) will notice or care if the AC-DC converter that runs the clock on your stove burns 5W at idle even though your wall clock can run on one AA battery for years, but they will notice and care if their camper battery is dead after leaving it parked for a couple weeks.
Today, I recommend using LiFePO4 batteries in whatever series cell arrangement gets you the required watt hours, regardless of that output voltage. Then run a modern, high-efficiency (high-frequency) digital inverter to bump the voltage up to whatever your local AC grid runs at. You can go 220V AC in the US if you really want more efficiency and smaller wires, and are willing to deal with the hassle of finding the right lightbulbs and international power cords and so on.
The problem is that the ampacity in a 12V DC light circuit is 10x that of an equivalent-power 120V AC system. And worse yet, power dissipation in a resistive element is equal to I^2 R, so you're heating the wiring harness with power losses are 100x worse than in a 120V system and almost 200x worse than a 220V system. So you have to oversize the wires to reduce R, which adds weight and cost. And if you drop 2V to line losses in your 12V system, your device is seeing 83% of the nominal voltage, while if you drop 2V in a 120V system (you won't, because Ohm says voltage drop is equal to IR, and I is 1/10th that of a 12V system), but still, you're 98% nominal.
They're running 12V because that's the voltage of a classic 6-cell lead-acid battery, and you probably didn't want 220V in your Model T, even with felted asbestos insulation, but I'd be confident enough to lick a modern XLPE wire carrying 220V. A century of using those lead acid batteries (and worse, 3-cell 6V systems...can't endorse converting your classic car to 12V enough...) created now-entrenched economies of scale for lamps, and switches, and pumps, and radios, and fans, and most of the other things you need in a boat or camper. The only advantage of using those 12V parts is that their manufacturers put a little more effort into making them efficient. No one (sadly) will notice or care if the AC-DC converter that runs the clock on your stove burns 5W at idle even though your wall clock can run on one AA battery for years, but they will notice and care if their camper battery is dead after leaving it parked for a couple weeks.
Today, I recommend using LiFePO4 batteries in whatever series cell arrangement gets you the required watt hours, regardless of that output voltage. Then run a modern, high-efficiency (high-frequency) digital inverter to bump the voltage up to whatever your local AC grid runs at. You can go 220V AC in the US if you really want more efficiency and smaller wires, and are willing to deal with the hassle of finding the right lightbulbs and international power cords and so on.
Doesn't a 48V DC installation provide a very reasonable compromise?
That's what I use for my off-grid solar installations, and it works pretty well. 4x less amps, and you still get a safe voltage.
That's what I use for my off-grid solar installations, and it works pretty well. 4x less amps, and you still get a safe voltage.
Yes, but there aren't many 48V DC appliances -- radios, lights, gauges, etc.
Many larger boats have 24V DC systems, and there are quite a few boat electronics that run on either 12V or 24V (though you will still need either a 24->12v converter for many things, or be able to tap 12v from the battery bank).
Many larger boats have 24V DC systems, and there are quite a few boat electronics that run on either 12V or 24V (though you will still need either a 24->12v converter for many things, or be able to tap 12v from the battery bank).
DC-DC buck converters got incredibly cheap and efficient, every small appliance can have one.
Yep, that's a great compromise. 40V, 56V, 80V, 48V outdoor power tools use the same voltage for many of the same reason (they're slowly moving away from 18V battery packs for anything high-power). Maybe after a few decades, RV suppliers will standardize on 48V DC lighting circuits, a standard 48V DC receptacle, and provide fans and smoke detectors and pumps and sensors and so on that run on 48V DC. Integrated circuits will emerge in quantity designed to rectify 48V down to whatever the LED drivers and microcontrollers and so on use, and eventually compete in economies of scale with those used in the 12V automotive world.
But good luck finding those parts today.
But good luck finding those parts today.
If you go diesel, you remove the need for spark, but perhaps starting is a greater challenge.
In the "quasi-DIY power generation space", take a look at Lister engines & their clones (Listeroids)[0]. You end up with a surprisingly efficient[1] engine when you run diesel that drives any belt system you want: flip from a generator to a mill to a water pump. They can run on most any alternative fuel you want to use - biodiesel, waste oils - and their simple low RPM construction means they are durable and easy to work on.
[0]: http://www.justliveoffgrid.com/InstallationGuide.html
[1]: https://diesel-bike.com/Lister_Gen/Lister1.html
[0]: http://www.justliveoffgrid.com/InstallationGuide.html
[1]: https://diesel-bike.com/Lister_Gen/Lister1.html
Lister engines also sound fantastic, in my opinion. Due to where I live, I often hear them going past me and it's wonderful to hear them throttle up as they potter on by.
I don't see how this conversion makes much sense. He started with a generator that was junked because the ICE was shot. He could have replaced that ICE with an off the shelf 4 cycle engine for under $1000.00. Instead, he's got a car that even as junk was worth half what the new engine would cost, with the space requirements that come with a car, the investment in electronics and build, and the net result is a junked nearly 200hp car running an generator that can only use maybe 10HP tops. A great job of McGivering up something, but I can't imagine why anyone would do the second one.
Plus now no one but him can repair it.
It's a super cool learning experience, and that's the value.
It's a super cool learning experience, and that's the value.
> Plus now no one but him can repair it.
electronics aside, you think fewer people can repair a toyota than a random generator? and i'm just talking about common-ase-tech-knowledge type stuff, to say nothing of the availability of parts.
electronics aside, you think fewer people can repair a toyota than a random generator? and i'm just talking about common-ase-tech-knowledge type stuff, to say nothing of the availability of parts.
Yes.
Small internal combustion engines are super simple, and small engine manufacturers like those that make generators have an equally impressive dealer, spare parts and repair network to automotive manufacturers.
In this case it was a harbor freight generator. They have lots of replacement engines available for very affordable prices (starting at less than $200) https://www.harborfreight.com/generators-engines/engines.htm...
I always say, why buy a Toyota when a lawnmower engine will do do? It's not like Toyotas are more common.
Small internal combustion engines are super simple, and small engine manufacturers like those that make generators have an equally impressive dealer, spare parts and repair network to automotive manufacturers.
In this case it was a harbor freight generator. They have lots of replacement engines available for very affordable prices (starting at less than $200) https://www.harborfreight.com/generators-engines/engines.htm...
I always say, why buy a Toyota when a lawnmower engine will do do? It's not like Toyotas are more common.
> In this case it was a harbor freight generator.
fair enough - i didn't watch the video and couldn't figure out what kind of genny it was.
> It's not like Toyotas are more common.
toyotas aren't more common than lawn mowers okay but cars are more common than lawn mowers (i looked it up to double check).
fair enough - i didn't watch the video and couldn't figure out what kind of genny it was.
> It's not like Toyotas are more common.
toyotas aren't more common than lawn mowers okay but cars are more common than lawn mowers (i looked it up to double check).
It is a seemingly free drivable generator. What's not to love?
When you disengage the cruise control clutch the car is still drivable, and he uses it to hoist around stuff and weld things.
When you disengage the cruise control clutch the car is still drivable, and he uses it to hoist around stuff and weld things.
Silly question: since a hybrid like a Prius is MEANT to be a generator (of sorts), would an old Prius be a better choice for a stationary generator? Lord knows they are pretty abundant and fairly cheap now.
Having lived 5 days without power in the wake of the Iowa derecho in August 2020, I now fully appreciate having an emergency source of electricity. Generators were not to be found, and many were stolen from people's yards, including one from an animal shelter. Gas and ice were hard to come by. Cooking was challenging for us since our stove was electric. My pellet grill was/is electric so we were unable to cook. After 3 days, we had to toss everything from the fridge and freezer.
https://www.plugoutpower.com/ makes a kit for the Prius (and others) to do just that!
Yes, because it's an Atkinson cycle engine so the engine efficiency is much better, and also because normal car alternators are absurdly inefficient; about 50% or so, I think. The Prius's motor-generator is more like 90%+ efficient.
The Prius's motor-generator might not be able to run at 100% duty cycle, but they're tens of kilowatts max output so you'd need a pretty big load.
Many car alternators also won't run at full load for very long, and can only do about 2kW, so definitely a risk. Either the windings overheat, or the voltage regulator will. They're sometimes thermally regulated, but not always. You can sort of band-aid it with forced cooling to supplement the centrifugal fan on them.
The Prius's motor-generator might not be able to run at 100% duty cycle, but they're tens of kilowatts max output so you'd need a pretty big load.
Many car alternators also won't run at full load for very long, and can only do about 2kW, so definitely a risk. Either the windings overheat, or the voltage regulator will. They're sometimes thermally regulated, but not always. You can sort of band-aid it with forced cooling to supplement the centrifugal fan on them.
Joey Hess's solar powered fridge system[0] is neat - instead of just storing energy in batteries he uses extra thermal mass[1].
[0] https://fridge0.branchable.com/ [1] https://fridge0.branchable.com/thermal_mass/
[0] https://fridge0.branchable.com/ [1] https://fridge0.branchable.com/thermal_mass/
I have an 1800 watt 12v inverter in the trunk of my Prius and have pre-wired AMP cables to the battery for easy hookup for any family member not as technically inclined. This is limited, but I was able to run the oil heat and Internet for a few days when a winter storm took out power. The engine only runs when it needs to recharge the hybrid battery, so it is very efficient compare to a standard generator.
You could probably get more power out with a custom inverter tied to the 140v hybrid battery, but this was quick and easy.
I tried to swap in the refrigerator for the heat, but I had grounding issues that was tripping the inverter. Fortunately it was cold out so I was able to manage. Just remember a DR plan isn't done until you have tested it all the way.
You could probably get more power out with a custom inverter tied to the 140v hybrid battery, but this was quick and easy.
I tried to swap in the refrigerator for the heat, but I had grounding issues that was tripping the inverter. Fortunately it was cold out so I was able to manage. Just remember a DR plan isn't done until you have tested it all the way.
If you tapped the traction batteries' output to an inverter there wouldn't be a way for the Prius to realize it wasn't operating normally with its strategy to keep the pack voltage in a ~30%-80% state of charge. It doesn't have a particularly large battery for the traction battery so I'd imagine it would run a lot unless you tie it to a larger pack. There are some folks retrofitting LiFePO4 cells with individual charge controllers to trick the NiMH hybrid system into using them. All the car controls look at is cell voltage.
I believe that the Japanese version of Prius (not sure if the regular one or PHEV) comes from the factory with this option - it can work as a full house generator as long as there is gas in the tank.
If I recall correctly, the prius ICE and EV systems are totally isolated and only connected by the road in between the front and rear tires. The ICE runs the front tires and the EV system is hooked up to the rear tires. You mostly charge the battery up by slowing the car down with the rear tires, so you'd need to modify the car with some belts or linkage between the front and rear drives.
In Toyota's hybrid synergy drive, the electric motor system is inputting to the same transmission as the ICE engine, and is an integral part of the casing. You can see a cutaway of it here to get an idea of what it looks like in practice: https://en.wikipedia.org/wiki/Hybrid_vehicle_drivetrain#/med... What you're describing is indeed how the E-Four system works for the rear wheels on the AWD versions of the Prius
Apparently they can only provide a maximum of three kilowatts of continuous power. Not enough for most folks but better than nothing in an emergency.
Not a budget option now, but this is a factory supported application on properly equipped F-150s. 240v@30A, available on the hybrid or EV only model (IMHO, more useful with the hybrid, cause you can probably drive to get more gas, or store some onsite, where it might be hard to find somewhere to drive to charge)
I suspect there can be much improvement in his rudimentary "control" algorithm. A simple PID controller could react much faster and zero in on the right throttle position in response to a varying load.
It was a bit painful watching that controller creep along.
It was a bit painful watching that controller creep along.
Comment on the video asked the same. Reply:
> That did occur to me and I think it's a good idea. I'll likely circle back to this project as my coding skills improve, I left a USB cable connected to the Arduino so updating the code will be super easy!
> That did occur to me and I think it's a good idea. I'll likely circle back to this project as my coding skills improve, I left a USB cable connected to the Arduino so updating the code will be super easy!
The entire time I was watching this I was thinking that a PID controller is exactly what is needed here.
Any idea why he did not opt for that?
Heck, he could have hacked the cruise controller itself to set the "speed" to 60 Hz.
Any idea why he did not opt for that?
Heck, he could have hacked the cruise controller itself to set the "speed" to 60 Hz.
Yep. Also the main loop should cycle as fast as possible, and only execute the control loop as needed. Or really use a timer interrupt.
Also, look into controlling the ECU directly instead of futzing around with mechanically controlling the cruise control (yuk).
And this really, really needs a proper RTOS and "software written by someone more professional than someone who tinkers with Arduinos", since malfunctioning software can destroy the engine and/or burn your house down.
For the same reason, it requires a proper PCB, not some yanky box of protoboard and wires.
And this really, really needs a proper RTOS and "software written by someone more professional than someone who tinkers with Arduinos", since malfunctioning software can destroy the engine and/or burn your house down.
For the same reason, it requires a proper PCB, not some yanky box of protoboard and wires.
You don't really need an RTOS to do something like this safely, but agree you need more firmware knowledge than "tinkers with Arduinos" to stay clear of possible unfortunate failure modes. You definitely need to build in some interlocks and/or other sanity checking.
Similar with the PCB's, many of the better dev boards are pretty decent, the problem comes with poor connections designed for easy access, etc. This can be resolved without spinning a new board though, or perhaps designing a simple extender.
Similar with the PCB's, many of the better dev boards are pretty decent, the problem comes with poor connections designed for easy access, etc. This can be resolved without spinning a new board though, or perhaps designing a simple extender.
Arduino is single threaded on bare metal — you don’t need RTOS in this case, afaict
3600rpm is pretty high. This thing must suck gas. You’d want to do some math to figure out if this approach was actually saving any money over a proper consumer generator. Reliabilty would also be a concern. Not the engine itself, but the integration of parts by the user.
looking at the video and his responses to comments, buddy is a machine-recycling nut just using this to give himself a mobile welder on his acreage or whatever.
he definitely knows it's a mad-max-by-way-of-something-awful "look what I made out of shit I had lying around" solution to a thoroughly solved problem. it's conceptually cool but it's a weird narrow use case and it's not an objectively good idea.
you could address cooling by using a motor with a big clutch fan and a well-shrouded rad, and you would probably be better off using the engine's idle control system to manage this at lower RPM to save gas, but it'd still be lipstick on a pig and you could go to harbour freight and buy a prettier pig.
he definitely knows it's a mad-max-by-way-of-something-awful "look what I made out of shit I had lying around" solution to a thoroughly solved problem. it's conceptually cool but it's a weird narrow use case and it's not an objectively good idea.
you could address cooling by using a motor with a big clutch fan and a well-shrouded rad, and you would probably be better off using the engine's idle control system to manage this at lower RPM to save gas, but it'd still be lipstick on a pig and you could go to harbour freight and buy a prettier pig.
Why would the high RPM necessarily mean using a lot of fuel? I've had a little VW Polo 1.0L that used to sit at 4000rpm just to go 70mph on the motorway, and it still returned like 50 imperial mpg(~6L/100km).
Essentially you want the motor to makes as few turns as possible for the same power output. At some low rpm the burn cycle gets bad though. Depends on motor.
Fuel effeniency charts need constant power lines to be useful or they fool people.
Fuel effeniency charts need constant power lines to be useful or they fool people.
Most Toyota Siennas were delivered with a 3.5L V6. The earliest models had a 3.0L. And they usually have an idle RPM around 700-800rpm.
Depends on the situation. Very occasional use and already having the engine is probably fine. If you have to buy an engine, or use it often, then the math is more important.
I find it interesting how folks here are always so much more critical of things like this, despite being generally outside of what the average HNer is experienced with or knowledgeable about.
Is this an ideal setup? Not even close, but you'll find mechanical people love to tinker with this kind of thing, myself included.
Is this an ideal setup? Not even close, but you'll find mechanical people love to tinker with this kind of thing, myself included.
The DIY is fun, but if you want to think about it on a larger scale:
https://academiccommons.columbia.edu/doi/10.7916/D81N8CPF
From the abstract:
> This thesis specifically highlights the value of small, mass-manufactured internal combustion piston engines retrofitted to participate in non-automotive system designs. The applications are unconventional and stem first from the observation that, when normalized by power output, internal combustion engines are one hundred times less expensive than conventional, large power plants.
And:
> The largest single component of this thesis is modeling, designing, retrofitting, and testing a reciprocating piston engine used as a compressor. Motivated again by the low cost of an internal combustion engine, this work looks at how an engine (which is, in its conventional form, essentially a reciprocating compressor) can be cost-effectively retrofitted to perform as a small-scale gas compressor.
https://academiccommons.columbia.edu/doi/10.7916/D81N8CPF
From the abstract:
> This thesis specifically highlights the value of small, mass-manufactured internal combustion piston engines retrofitted to participate in non-automotive system designs. The applications are unconventional and stem first from the observation that, when normalized by power output, internal combustion engines are one hundred times less expensive than conventional, large power plants.
And:
> The largest single component of this thesis is modeling, designing, retrofitting, and testing a reciprocating piston engine used as a compressor. Motivated again by the low cost of an internal combustion engine, this work looks at how an engine (which is, in its conventional form, essentially a reciprocating compressor) can be cost-effectively retrofitted to perform as a small-scale gas compressor.
> when normalized by power output, internal combustion engines are one hundred times less expensive than conventional, large power plants.
That's quite the caveat because with the higher power output comes far lower efficiency. That's fine for an emergency backup scenario, or for spinning reserves as the paper mentions, but it's a very operationally expensive for normal power generation. The idea of modularity is good, but that's already a part of the VPPs that are being built now.
That's quite the caveat because with the higher power output comes far lower efficiency. That's fine for an emergency backup scenario, or for spinning reserves as the paper mentions, but it's a very operationally expensive for normal power generation. The idea of modularity is good, but that's already a part of the VPPs that are being built now.
Isn't that market already served by portable generators? Engine manufacturers like Honda have been selling gas generators forever.
That 2 pole generator is meant for single cylinder gas engines screaming at 3600 RPM. Larger generators are 4 pole so they can turn at 1800 RPM for 60Hz and 1500 for 50Hz.
And 5500W is not powerful IMO. That is a standard portable gas generator head. The car engine is way overpowered and likely not operating near efficiency.
[] AC motor or generator speed: RPM = 120f/p, where f is in Hz, p is number of poles.
And 5500W is not powerful IMO. That is a standard portable gas generator head. The car engine is way overpowered and likely not operating near efficiency.
[] AC motor or generator speed: RPM = 120f/p, where f is in Hz, p is number of poles.
I don't think this is a solution one would consider when perfection is desired, so I wouldn't worry much about critiquing projects like this one.
The main problem I see here is that everyone I've known with spare old cars littering their property seem to always be missing the engine.
In people’s yards, this is often the case.
There must be 1000s of cars in scrap yards, though, with perfectly functional engines and front ends.
Both my wife and myself have had a car written off after being rear ended. It is a common story.
There must be 1000s of cars in scrap yards, though, with perfectly functional engines and front ends.
Both my wife and myself have had a car written off after being rear ended. It is a common story.
If they're in a scrap yard they're most likely being parted-out, so the engine will be bought and put in another car.
The engine is for sale if you want to buy it. Most engine will last longer than the car if you take care of it. Back in the 1950s engines were a lot more likely to fail and so people would keep an old car running by buying a junkyard engine. Now that isn't very popular (it still happens, but it isn't popular)
I think this is what I was trying to point out. Engines are everywhere.
Winter and road salt ends way more vehicle lives than engine failure where I live.
My 2011 Ford Focus, for example, is slowly returning to nature. I can find dozens of them with engines in great shape, but also with body problems. Body work is incredibly expensive.
Winter and road salt ends way more vehicle lives than engine failure where I live.
My 2011 Ford Focus, for example, is slowly returning to nature. I can find dozens of them with engines in great shape, but also with body problems. Body work is incredibly expensive.
Yeah, if frame rot doesn't kill the vehicle (maybe you don't live in the rust belt for instance), then it's usually the transmission that sends the car to the chopper. Engines tend to outlast the rest of the car as long as the owner keeps up with basic maintenance. Plus, when things break on the engine they're usually fixable short of blowing a crank through the side of the block or something catastrophic like that. A body that is rotting out is hopeless, nobody is even going to try to fix it.
Where you'll have a lot more trouble is finding a large generator to bolt onto that engine. Those are far more rare. As many people have pointed out, sticking a little 5kW generator on the side of a full size car engine is a hilarious mismatch that's going to burn way more fuel than necessary. Sure it's a fun project, but quite impractical. Harbor Freight actually sells the appropriate replacement engine for $180, that van is worth more in scrap value than that. Plus it takes forever to stabilize the frequency so it's not even as good as the standard setup.
Maybe the best use for this would be some Mad Max style post apocalypse where most all technology has been lost, but gasoline is abundant and apparently free so people spend their time making heavy metal looking art cars and sports equipment.
Where you'll have a lot more trouble is finding a large generator to bolt onto that engine. Those are far more rare. As many people have pointed out, sticking a little 5kW generator on the side of a full size car engine is a hilarious mismatch that's going to burn way more fuel than necessary. Sure it's a fun project, but quite impractical. Harbor Freight actually sells the appropriate replacement engine for $180, that van is worth more in scrap value than that. Plus it takes forever to stabilize the frequency so it's not even as good as the standard setup.
Maybe the best use for this would be some Mad Max style post apocalypse where most all technology has been lost, but gasoline is abundant and apparently free so people spend their time making heavy metal looking art cars and sports equipment.
After the apocalypse gas is free for 3 months if you can get it out of the tanks. After that it is rotted away and not usable. Diesel should last longer, but you have to watch for algae growth.
There is a term for this: a "front clip." The recycling yard chops the car somewhere behind the firewall.
There are tons of old functioning car engines out there. Go check out any state that salts their roads, the bodies of older cars are almost gone but thanks to the consistent oil leaks and oil spills over the block the engines are generally clean underneath the grime. If you don't got anything special that people like to tune up and it doesn't self destruct for being a shitty design then there isn't much demand for them, most of their cars are scrapped with another 150K miles or more left on the block.
Could jack up a working car and put it in cruise control and fasten the alternator directly to a wheel hub
Tractors have PTOs and are meant to be run at high load for long periods of time while stationary.
On the family farm, we had a PTO driven generator for use when the power was out.
On the family farm, we had a PTO driven generator for use when the power was out.
A working car already has an alternator. Just plug in to that.
Or replace it with a bigger one that has more output (and thus more drag on the engine), and upgrade the belt for longevity. Then the car's built in electronics will handle keeping the throttle in the right place for idle.
I'm in the process of designing a Sprinter mobile office roadtrip starlink vehicle with an asston of batteries in it, and upgrading the alternator so that the batteries are always charging from the diesel engine whenever underway is like step #1.
I'm in the process of designing a Sprinter mobile office roadtrip starlink vehicle with an asston of batteries in it, and upgrading the alternator so that the batteries are always charging from the diesel engine whenever underway is like step #1.
A high powered alternator and a carbureted engine with mechanical timing and nothing else on the engine but a starter, exhaust, flywheel, and cooling seems ideal.
Something like this: https://www.powerbastards.com/proddetail.asp?prod=Fitzall-22...
That way you can set the starter idle for high RPMs to get the system up to speed with the resistance from the alternators and then set the idle speed at the ideal speed for the alternator to produce the most power.
But even on a 4 cylinder engine you're going to have horsepower to spare, so you may want multiple alternators wired in series with beefy transfer bars, so build a custom mounting plate for as many as it takes to almost bog down the engine at 1200 rpm or so.
These $350 alternators produce 220 amps at 14.6 volts at 1200 rpm, or 3200 watts each. I imagine you could run at least 3 of them on a properly set up 4 cylinder engine. That's getting close to 10 kilowatts of power before conversion and you would probably still not be taxing the system.
On the other hand, at this point you've spent $2,000 or so and a month of backyard engineering time to build an 8000 watt generator when you can buy a 13,500 watt generator at lowes for $1,300 dollars.
If you have a good motor you can run on a stand and a bunch of cheap or free alternators, then you just need the mounting system and inverter. Typical alternators put out about 40-80 amps, or 580-1200 watts. That at least has a chance of being cheaper.
Something like this: https://www.powerbastards.com/proddetail.asp?prod=Fitzall-22...
That way you can set the starter idle for high RPMs to get the system up to speed with the resistance from the alternators and then set the idle speed at the ideal speed for the alternator to produce the most power.
But even on a 4 cylinder engine you're going to have horsepower to spare, so you may want multiple alternators wired in series with beefy transfer bars, so build a custom mounting plate for as many as it takes to almost bog down the engine at 1200 rpm or so.
These $350 alternators produce 220 amps at 14.6 volts at 1200 rpm, or 3200 watts each. I imagine you could run at least 3 of them on a properly set up 4 cylinder engine. That's getting close to 10 kilowatts of power before conversion and you would probably still not be taxing the system.
On the other hand, at this point you've spent $2,000 or so and a month of backyard engineering time to build an 8000 watt generator when you can buy a 13,500 watt generator at lowes for $1,300 dollars.
If you have a good motor you can run on a stand and a bunch of cheap or free alternators, then you just need the mounting system and inverter. Typical alternators put out about 40-80 amps, or 580-1200 watts. That at least has a chance of being cheaper.
I don't think that will be able to power up my home defense tesla coil
I don't think most differentials would enjoy that, even open ones.
Bingo.
How is the “school bus on front lawn” aesthetic avoided?
Bury the schoolbus as a fallout shelter!
Easy! Keep it in the backyard
Might need to be careful about doing that: https://www.youtube.com/watch?v=BAjAySmuvz0
More unaccountable nonsense "technocratic" fake job bullshit. Get mandated rent from the boring beige-loving 90%, dump the 10% that somehow stick out.
Also, that backyard looks like the least cluttered part of that neighborhood. I can't imagine being so scared of living in a multi story building that I'd do that to myself.
Also, that backyard looks like the least cluttered part of that neighborhood. I can't imagine being so scared of living in a multi story building that I'd do that to myself.
While most people here seem to worry about cooling the engine, if you did this with a modern high-efficiency diesel, like a recent VW 2.0 TDI, the engine would probably struggle to reach any kind of operating temperature at all.
Here in Morocco, 80s era car engines are still being converted to run on butane/propane and used to generate electricity to run well pumps (their favorite is the Mercedes M102 E23).
Where we live power goes out occasionally so I keep a modern 2.8kva inverter generator which is enough to power my office/internet and a few core household items.
I was looking at powering the entire house more completly and looked at one of these: https://www.scintex.com.au/products/tractor-pto-generator
Basically you can connect this to the back of a tractor via PTO and you get significant power generation for a reasonable price relative to buying the equivalent standalone generator. This assuming you have a tractor... don't we all?
If someone was interested in backup powering a whole house type thing there is regularly older tractors going for cheap and those engines are really built to work. Might be worth considering vs a car engine.
I was looking at powering the entire house more completly and looked at one of these: https://www.scintex.com.au/products/tractor-pto-generator
Basically you can connect this to the back of a tractor via PTO and you get significant power generation for a reasonable price relative to buying the equivalent standalone generator. This assuming you have a tractor... don't we all?
If someone was interested in backup powering a whole house type thing there is regularly older tractors going for cheap and those engines are really built to work. Might be worth considering vs a car engine.
Without question, if you've got a tractor you can rely on, I would get a PTO-driven generator for backup. Even a little 30HP diesel tractor will power a 15kw generator, which is big enough for almost any household as backup. Farms typically have the grown version of these (if your small tractor is 100hp, as is the case for farms around here, no reason not to have a 50kw backup generator).
Lots of wasted energy using an entire bulky engine and all of the friction, lubrication, and electronics and sensor requirements (anything newer than 1985 is unsuitable) of it as a "generator". Taking the alternator out and converting it to hydroelectric or wind power is completely doable. That's all you need as the basis for generation. You don't need an entire car.
One nice thing about alternators is they are constant voltage sources 14.4V DC over a wide range of RPM inputs after rectification by the trio from 3 phase AC and cleaned up with the VRM. This should be connected to a car battery with very short, very big leads because the voltage is low but the current is high (like a starter). From there, also use short/large leads to either use DC power directly or use a high efficiency inverter (smaller ones are cheap and ubiquitous). Congrats, that's your budget OTG setup.
The current rating of the windings, VRM, and of the trio will determine maximum current output. Typically, 2-10 HP will max out an alternator with a rating in the range of 40-200A (560 - 2kW). This is another reason why using a whole automotive engine is pointless: because it's oversized by 2 orders of magnitude.
The most difficult thing about powering an alternator non automotive use is increasing the gear enough and mounting it somewhere secure enough to put enough tension on the belt. Rarely will you ever direct drive an alternator.
Hydroelectric power with a high head, even with a relatively small stream, contains an enormous amount of potential energy. A Pelton wheel in direct drive maybe possible, but it would probably need slight gear reduction (smaller pulley than the alternator's under high tension with quality bearings on both) for maximum efficiency because the wheel would could be spinning 8k+ RPM.
https://www.energy.gov/energysaver/microhydropower-systems
You can remove the VRM and get ~28VDC but it's going to be ugly and un-regulated. A battery of some sort is required to energize the field coil or no power will be generated.
One nice thing about alternators is they are constant voltage sources 14.4V DC over a wide range of RPM inputs after rectification by the trio from 3 phase AC and cleaned up with the VRM. This should be connected to a car battery with very short, very big leads because the voltage is low but the current is high (like a starter). From there, also use short/large leads to either use DC power directly or use a high efficiency inverter (smaller ones are cheap and ubiquitous). Congrats, that's your budget OTG setup.
The current rating of the windings, VRM, and of the trio will determine maximum current output. Typically, 2-10 HP will max out an alternator with a rating in the range of 40-200A (560 - 2kW). This is another reason why using a whole automotive engine is pointless: because it's oversized by 2 orders of magnitude.
The most difficult thing about powering an alternator non automotive use is increasing the gear enough and mounting it somewhere secure enough to put enough tension on the belt. Rarely will you ever direct drive an alternator.
Hydroelectric power with a high head, even with a relatively small stream, contains an enormous amount of potential energy. A Pelton wheel in direct drive maybe possible, but it would probably need slight gear reduction (smaller pulley than the alternator's under high tension with quality bearings on both) for maximum efficiency because the wheel would could be spinning 8k+ RPM.
https://www.energy.gov/energysaver/microhydropower-systems
You can remove the VRM and get ~28VDC but it's going to be ugly and un-regulated. A battery of some sort is required to energize the field coil or no power will be generated.
Fascinating to watch the larger (professional) generator doing their work
https://m.youtube.com/watch?v=SzKu9QBGI4s
I always think what happens when they fail to sync in time -- a bad day for a datacenter or worse
https://m.youtube.com/watch?v=SzKu9QBGI4s
I always think what happens when they fail to sync in time -- a bad day for a datacenter or worse
power grids and similar have gauges that can show phase offset between 2 supplies, in the old days they would have to flick the switch once it was exactly pointing to zero offset, but would assume modern equipment can do it automatically.
There is a version of The Whole Earth Catalog that describes plans to turn an old car into a 10kW generator, enough to power a small off-the-grid town. I think they used the carborator to set the engine speed, so it didn't keep perfect 60Hz output but was good enough to run most appliances. I forget which version of the catalog it was in, one of the early ones I think. Maybe the generator itself was an old motor used as a generator, perhaps manually rewound?
We got a whole house generator this year. It’s tied into the natural gas line and has a transfer switch that auto switches over when power is lost.
I like DIY stuff, but the convenience of not doing DIY for something like this is great.
Now… one thing that could be improved is there’s an 8 or so second loss of power while the generator spins up. If the whole house could run on batteries and the generator charge the batteries when mains can’t that would be awesome. But that solution would be very expensive right now.
I like DIY stuff, but the convenience of not doing DIY for something like this is great.
Now… one thing that could be improved is there’s an 8 or so second loss of power while the generator spins up. If the whole house could run on batteries and the generator charge the batteries when mains can’t that would be awesome. But that solution would be very expensive right now.
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120VAC is a waste if you are trying to generate power locally. Unless it's just for a few days or a week.
Better to have 12VDC backups of whatever you need. Lights, refrigerator, fans, electronics. Like a semi cab. Then a wood stove for heat and cooking.
Then the 12VDC can come from solar, wind, batteries, car engines, bicycles, etc.
Better to have 12VDC backups of whatever you need. Lights, refrigerator, fans, electronics. Like a semi cab. Then a wood stove for heat and cooking.
Then the 12VDC can come from solar, wind, batteries, car engines, bicycles, etc.
Everything you talked about generally runs on 120V DC. You are basically suggesting changing everything in your house to save some money on inverter.
It isn't possible to run full-sized fridge on 12V DC with reasonably sized wires. It is more efficient to run 12V generator through inverter, 120V AC over the wires to AC gear, and convert back down to 12V for the things that need it.
It isn't possible to run full-sized fridge on 12V DC with reasonably sized wires. It is more efficient to run 12V generator through inverter, 120V AC over the wires to AC gear, and convert back down to 12V for the things that need it.
I'd like to keep my house running on 12v DC, I lived in an RV for a while and I liked it. All the lighting was 12v LEDs, there was an inverter for the fridge and some plugs. I'd probably do a similar setup, I could probably build the whole thing salvaging a dead RV and buying some lithium iron phosphate batteries. All I really need to run on 120v AC would be a refrigerator or two.
Is this safe? It's a cool idea and I'd appreciate even the slightest discussion of potential risks of the motor coming apart, or whatever else failure mode (I don't know)
Hell, no, it is not safe. That box of Arduino madness is going to fail sooner rather than later, and destroy the motor, the person's house wiring or both.
not sure how its going to destroy the motor, and most it can fail and set the equivalent to the accelerator being foot to the floor, at that point the engine will just bounce off the ECU governed rev limiter until he turns the engine off.
If there's no system to shut down the engine on overheating of coolant or oil, you're definitely looking at a fire hazard.
The bigger issue is the terrible efficiency; alternators are about 50% efficient, whereas proper mechanical generators are 90%+.
The better solution would be to buy a "generator head" and connect it to the engine...but by the time you get done making a frame to hold the generator, engine, fuel tank, radiator, expansion tank, etc - as well as the necessary safety systems - you might as well just have bought an used generator.
The bigger issue is the terrible efficiency; alternators are about 50% efficient, whereas proper mechanical generators are 90%+.
The better solution would be to buy a "generator head" and connect it to the engine...but by the time you get done making a frame to hold the generator, engine, fuel tank, radiator, expansion tank, etc - as well as the necessary safety systems - you might as well just have bought an used generator.
About as safe as any other use of a motor. Moving parts like belts and fans are potentially a problem.
The engine won't come apart in a dangerous way. It might overheat, which creates superheated water in the cooling system, which is designed to handle that. Although I sort of doubt it since they are basically using about 1/20th of its maximum power output.
The most dangerous thing about this is likely the standard risks of any generator, fuel and electricity.
The engine won't come apart in a dangerous way. It might overheat, which creates superheated water in the cooling system, which is designed to handle that. Although I sort of doubt it since they are basically using about 1/20th of its maximum power output.
The most dangerous thing about this is likely the standard risks of any generator, fuel and electricity.
[deleted]
60.73 is not great
For 99.9999% of applications it won't matter.
If you are powering your home with a Toyota minivan, I don't think you are concerned with grid sync or accurate time keeping.
If you are powering your home with a Toyota minivan, I don't think you are concerned with grid sync or accurate time keeping.
[deleted]
60.73 roentgen? Not great, not terrible.
60.73 is the frequency in hertz from the picture in the article.
They gave them the propaganda number.
Parts 1 and 2 do explain a lot of the decisions made, and I liked the process of improvising with lots of experience.
are cars designed to be left stationary with the engine running for long periods of time?
Engines are designed and built for cars, but there is a secondary market for stationary engines for various other applications. None of them are large enough markets to design their own engine (even all together), but they are large enough market that if you have already are designing an engine it is worth making a few changes to better serve other markets.
If you buy direct from the manufacture they probably have a custom computer code for generator use. This includes a pin, to select between 50 and 60 hz. If you are buying for a different use you won't get that pin, but might get some other controls not needed on a car (you will have to pay for custom programming of course). You have to check with your manufacture rep to see details - some companies are more interested in this business than others.
If you buy direct from the manufacture they probably have a custom computer code for generator use. This includes a pin, to select between 50 and 60 hz. If you are buying for a different use you won't get that pin, but might get some other controls not needed on a car (you will have to pay for custom programming of course). You have to check with your manufacture rep to see details - some companies are more interested in this business than others.
Depends on how much power you pull out of it and the model. Every decent car in working order should be able to run at an idle witho AC and such running without getting dangerously hot. But your intuition is correct, they aren't expecting to be outputting that much power without also getting additional airflow from moving.
With a water cooled engine though all you really have to do in most cases is either put more fans on the radiator or hook up a larger radiator to increase cooling levels if the stock equipment can't keep up.
With a water cooled engine though all you really have to do in most cases is either put more fans on the radiator or hook up a larger radiator to increase cooling levels if the stock equipment can't keep up.
Nope, you’d need to find a way to cool the engine. A car has a water pump that moves water through the engine and to a radiator. The cars motion moves air across the radiator. Most cars have an electric fan so they can run at idle, but they aren’t designed to idle indefinitely. Police cars in the US often have (or at least had) beefed up cooling system to allow them to run at idle.
Cars during tests on dynamometer have to have a big fan blowing constantly on radiator. If you provide a big enough fan, you can run it as long as you want, even with big load. I was once doing 140km/h on autobahn uphill with fully loaded passenger car with additional fully loaded roof trailer. The car managed half an hour of fully open throttle without any problems, but If your home needs to use 40kW for more than a hour, maybe investing in proper generator is a better solution. In typical applications, engine will not be running at full power.
No - but used this way it's no longer a car.
Not at the rpms he is running.
How do you make this safe, electrically? In terms of earthing, circuit breaking, etc.?
hopefully you reuse the circuit breaker from the original and so are fine.
If you are running your house use a proper line/generator selector, and then your house grounds take care of earthing.
If you are running tools outdoors on a cord you don't want an earth, just make sure all your cords are in good shape. With no earth connection if you touch a live wire you won't get a shock as there is no circuit. Although this is safer for temporary use you can't do it for indoor/permanent use because you can't insect the wires in your walls to ensure they are in good shape, and so you can get a lot of failure modes that running good cords prevents, and earth protects against those.
If you are running your house use a proper line/generator selector, and then your house grounds take care of earthing.
If you are running tools outdoors on a cord you don't want an earth, just make sure all your cords are in good shape. With no earth connection if you touch a live wire you won't get a shock as there is no circuit. Although this is safer for temporary use you can't do it for indoor/permanent use because you can't insect the wires in your walls to ensure they are in good shape, and so you can get a lot of failure modes that running good cords prevents, and earth protects against those.
Something hippies and cab company owners have known for decades. Very cool.
Why not use a motorcycle engine?
reinventing hybrid electric cars
When our electric power went out 2 months ago, I started thinking about
emergency power. Our outage was unusually long, 2 days, because lightening hit a tree which fell on our overhead power lines to the house and pulled down all the lines, conduit, electrical boxes, etc.
Got a little electrical meter and showed that usually my office (I'm writing software) uses a grand total of 55 Watts, maybe 100 W if I do more, maybe 1000 Watts if I use the laser printer, boot my tower case Web server with several hard disk drives and an AMD 8 core processor, a little more in the kitchen for the refrigerator and occasional use of the microwave oven and toaster, a little more if I want to keep the winter heat, fueled by natural gas, going. For the hours of an outage, I'll f'get about running the air conditioner, oven, washer, and dryer.
Soooo, I can get by at 50 Watts and can do pretty well for a few days at peaks of 2000 Watts and an average over time of likely under 1000 Watts.
Okay, and I have a car! Yup, a car has an engine and generator, both very well designed!
A little shopping shows that I can get a box that will output 3200 -- 15,000 (in steps of about 2000) Watts, a different box for each step of 2000, of US standard 60 Hertz (Hz, cycles per second) A/C (alternating current, with a good approximation to the standard sine wave) at 120 Volts from any 12 Volt DC (direct current) storage battery. Just clip two leads onto the battery and run extension cords from the output of the box and keep the electrical loads I mentioned running.
So, I could get a box that can output 4000 Watts ...!
And I have a car! Hmm. Soooo, back the car out of the garage, raise the hood, set the box on a front fender of the car, attach the two leads from the box to the car battery, start the engine, just let the engine idle, run the extension cords from the output of the box to my office, kitchen, and, maybe, natural gas powered furnace, and, ..., check the amount of gasoline in the car's tank!
Since I don't need much power, the car and the box would keep me going for a few hours or ~2 days of an outage.
Uh, ..., don't have to be very inventive because there is something of an industry serving people with campers, trailers, off-grid cabins in the woods, etc. who do a lot with getting power from batteries, gasoline powered generators, etc.
In short, just clip two leads onto the car battery, start the engine, let it idle (the car knows how to keep the battery charged without overcharging), run the extension cords, and wait for the local electric power utility to get the outage fixed!
For the horrors of back feeding power to the whole house and maybe electricuting utility workers, etc., "no worries, mate": Are NOT trying to power the whole house. Instead, are just powering a few loads with extension cords. E.g., my office loads plug into the female sockets of a power strip which plugs into the wall. Soooo, just unplug the power strip from the wall and plug its male plug into the female socket at the end of one of the extension cords. Same for each of the microwave oven, toaster, refrigerator. For the electric power used by the natural gas powered furnace, that will have to be a little more involved. But, again, are just running the electric loads much like would on a camping trip. "No worries, Mate!".
Got a little electrical meter and showed that usually my office (I'm writing software) uses a grand total of 55 Watts, maybe 100 W if I do more, maybe 1000 Watts if I use the laser printer, boot my tower case Web server with several hard disk drives and an AMD 8 core processor, a little more in the kitchen for the refrigerator and occasional use of the microwave oven and toaster, a little more if I want to keep the winter heat, fueled by natural gas, going. For the hours of an outage, I'll f'get about running the air conditioner, oven, washer, and dryer.
Soooo, I can get by at 50 Watts and can do pretty well for a few days at peaks of 2000 Watts and an average over time of likely under 1000 Watts.
Okay, and I have a car! Yup, a car has an engine and generator, both very well designed!
A little shopping shows that I can get a box that will output 3200 -- 15,000 (in steps of about 2000) Watts, a different box for each step of 2000, of US standard 60 Hertz (Hz, cycles per second) A/C (alternating current, with a good approximation to the standard sine wave) at 120 Volts from any 12 Volt DC (direct current) storage battery. Just clip two leads onto the battery and run extension cords from the output of the box and keep the electrical loads I mentioned running.
So, I could get a box that can output 4000 Watts ...!
And I have a car! Hmm. Soooo, back the car out of the garage, raise the hood, set the box on a front fender of the car, attach the two leads from the box to the car battery, start the engine, just let the engine idle, run the extension cords from the output of the box to my office, kitchen, and, maybe, natural gas powered furnace, and, ..., check the amount of gasoline in the car's tank!
Since I don't need much power, the car and the box would keep me going for a few hours or ~2 days of an outage.
Uh, ..., don't have to be very inventive because there is something of an industry serving people with campers, trailers, off-grid cabins in the woods, etc. who do a lot with getting power from batteries, gasoline powered generators, etc.
In short, just clip two leads onto the car battery, start the engine, let it idle (the car knows how to keep the battery charged without overcharging), run the extension cords, and wait for the local electric power utility to get the outage fixed!
For the horrors of back feeding power to the whole house and maybe electricuting utility workers, etc., "no worries, mate": Are NOT trying to power the whole house. Instead, are just powering a few loads with extension cords. E.g., my office loads plug into the female sockets of a power strip which plugs into the wall. Soooo, just unplug the power strip from the wall and plug its male plug into the female socket at the end of one of the extension cords. Same for each of the microwave oven, toaster, refrigerator. For the electric power used by the natural gas powered furnace, that will have to be a little more involved. But, again, are just running the electric loads much like would on a camping trip. "No worries, Mate!".
If the car's alternator is for example, 100A like it is in my car, that means the maximum output is 1200w. So if you use a 2000w inverter you'll be draining the battery at peak load. Just something to keep in mind so you aren't stuck with a car that won't start (or even run if it gets too low, as the fuel injectors will have too little voltage to fire).
Thanks for the alternator current of 100 Amperes and 1200 Watts -- I didn't have that data!
If I run the battery down, then I'll just have to wait until the electric utility restores the power! Then I'll have to recharge the battery! For that, I do have a battery charger.
Curiously, the battery charger puts out only 14 Amperes!!!
The charger and a lot on this whole subject has lots of warnings about how fast should charge a car battery -- their advice is to charge slowly or damage the battery, ..., explosions, etc.!!!
Ah, they didn't get to college like I did: Had an old Chevy, stick shift. Somehow, too often, when I tried to drive to college for the first class, the battery was dead. Hmm ....
Well, the driveway went downhill a little to the street. Sooo, with the door to the driver's side open, I stood by the steering wheel and got the car rolling rolling backwards downhill -- jumped in, closed the door, and aimed the car in the downhill direction on the street. Again with the driver's door open, with the transmission in neutral, got the car rolling downhill, reached in, swatted the shift lever down to engage 3rd, High gear, kept pushing, and right away the engine tried to start but, with 3rd engaged, struggled. I jumped in, pushed down on the clutch, put the shift into Neutral, gave some gas, pulled the door shut, and drove to class! After about the 15 minutes of driving to class, the battery was nicely enough charged to start the engine -- the dead battery problem was solved until the next dead battery problem!
Lesson 1: If listen to the usual rules of safe operation of a car, won't get to class on time!
Lesson 2: Can give a battery a nice charge quickly, e.g., 15 minutes!
Another issue: At one point I did discover that the battery charger won't do any charging at all for a fully dead battery. So, I just got a laboratory style DC power supply and used it to give the dead battery an initial charge and then used the charger intended and finished charging.
If I run the battery down, then I'll just have to wait until the electric utility restores the power! Then I'll have to recharge the battery! For that, I do have a battery charger.
Curiously, the battery charger puts out only 14 Amperes!!!
The charger and a lot on this whole subject has lots of warnings about how fast should charge a car battery -- their advice is to charge slowly or damage the battery, ..., explosions, etc.!!!
Ah, they didn't get to college like I did: Had an old Chevy, stick shift. Somehow, too often, when I tried to drive to college for the first class, the battery was dead. Hmm ....
Well, the driveway went downhill a little to the street. Sooo, with the door to the driver's side open, I stood by the steering wheel and got the car rolling rolling backwards downhill -- jumped in, closed the door, and aimed the car in the downhill direction on the street. Again with the driver's door open, with the transmission in neutral, got the car rolling downhill, reached in, swatted the shift lever down to engage 3rd, High gear, kept pushing, and right away the engine tried to start but, with 3rd engaged, struggled. I jumped in, pushed down on the clutch, put the shift into Neutral, gave some gas, pulled the door shut, and drove to class! After about the 15 minutes of driving to class, the battery was nicely enough charged to start the engine -- the dead battery problem was solved until the next dead battery problem!
Lesson 1: If listen to the usual rules of safe operation of a car, won't get to class on time!
Lesson 2: Can give a battery a nice charge quickly, e.g., 15 minutes!
Another issue: At one point I did discover that the battery charger won't do any charging at all for a fully dead battery. So, I just got a laboratory style DC power supply and used it to give the dead battery an initial charge and then used the charger intended and finished charging.
tl;dr: This setup worries me a bit, maybe talk it over with someone qualified in this, e.g. electrician, off-grid electrics expert.
At 4000W you are looking at around 300A on the 12V side. This requires chunky copper and clamps. Keep in mind the already quite big cables to jump cars are only rated for very short usage. Not saying it can't be done, but this amount of current certainly worries me.
Then you have the issue of protecting the 120V loads. You can get more than 20A of current out of the alternator, which pushes what you can safely put through standard extension cords. Usually running a single device off an alternator or generator is fine, but once you have multiple devices, hooked up to power strips, you can run into failure modes (with defective devices) that can cause shocks.
At 4000W you are looking at around 300A on the 12V side. This requires chunky copper and clamps. Keep in mind the already quite big cables to jump cars are only rated for very short usage. Not saying it can't be done, but this amount of current certainly worries me.
Then you have the issue of protecting the 120V loads. You can get more than 20A of current out of the alternator, which pushes what you can safely put through standard extension cords. Usually running a single device off an alternator or generator is fine, but once you have multiple devices, hooked up to power strips, you can run into failure modes (with defective devices) that can cause shocks.
> This requires chunky copper and clamps.
Yup. But that engineering issue is the responsibility of the designers of the DC/AC converter "box"!!!
> Then you have the issue of protecting the 120V loads. You can get more than 20A of current out of the alternator, which pushes what you can safely put through standard extension cords.
Naw!!! The car's alternator charges the car's 12 Volt battery, and the DC/AC converter "box" takes the 12 Volts from the battery and makes 120 Volts AC available at the female output sockets. So, if I plug the male end of an extension cord into one of those sockets and connect the female end of the cord to the male end of a power strip with female sockets and have my office lights and electronics, the "loads", connected to the power strip, no more current will flow in the extension cord than is requested, as usual, by the loads. A cord that can carry 16 Amperes, at 120 Volts, would be moving
16 * 120 = 1920 Watts
As I type this, my office is drawing 52 Watts. With my server with its 8 core AMD processor and my laser printer, still looking at a lot less than 1920 Watts. And the printer gets only occasional use and then for only seconds at a time.
The DC/AC converter has more than one female socket supplying 120 Volts, and from that and an ordinary extension cord could drive the refrigerator, toaster, and microwave oven -- again much less than 1920 Watts.
If I start to overload the DC/AC converter, not very likely for my loads and a converter that can supplyk 4000 Watts, I trust that the converter will have a circuit breaker. In that case, this approach to emergency electric power should be not much more of a safety challenge than normal usage.
Note in all of this, the circuit breaker in the house does not get involved, remains ON, and waits for the utility power to come back on. Then the lights in the kitchen, front hall, etc. will come back on, and I will plug my office and kitchen loads into the wall sockets again, disconnect the DC/AC converter, put the car back in the garage, wind up the extension cords, make some notes, and f'get about the outage!
One little issue is: If the Web server computer was running when the power went out, might there be a way to have power to that computer not be interrupted all the way until the power comes back on? Yup: With some shopping, can run the server computer off another box, not very big, that has a little battery inside that can keep the computer running for a few minutes while I switch over to the DC/AC converter and again while I switch back to the utility power.
For the Hacker News audience, this is conversation is drifting into kindergarten level talk: I'm SURE Hacker News has MANY very well informed engineers on how to have un-interruptible electric power to computers in a server farm and also to the whole farm.
For more, once I wrote a math paper on detecting zero day problems, gave an invited talk at the NASDAQ headquarters, and got a tour and overview of the engineering they did for un-interruptible NASDAQ service, uh, including a remote backup server location. Such magnificent engineering has long been available.
Here I am just trying to contribute to the issue of this thread, using the engine in a car to supply standard 120 Volt A/C electric power. I'm just mentioning that for short term power outages, maybe only a few hours at a time, should be able to do okay with just a normal car and a little box that can supply 4000 Watts of 120 Volt A/C power from a 12 Volt DC battery. That's all I'm trying to do.
Yup. But that engineering issue is the responsibility of the designers of the DC/AC converter "box"!!!
> Then you have the issue of protecting the 120V loads. You can get more than 20A of current out of the alternator, which pushes what you can safely put through standard extension cords.
Naw!!! The car's alternator charges the car's 12 Volt battery, and the DC/AC converter "box" takes the 12 Volts from the battery and makes 120 Volts AC available at the female output sockets. So, if I plug the male end of an extension cord into one of those sockets and connect the female end of the cord to the male end of a power strip with female sockets and have my office lights and electronics, the "loads", connected to the power strip, no more current will flow in the extension cord than is requested, as usual, by the loads. A cord that can carry 16 Amperes, at 120 Volts, would be moving
16 * 120 = 1920 Watts
As I type this, my office is drawing 52 Watts. With my server with its 8 core AMD processor and my laser printer, still looking at a lot less than 1920 Watts. And the printer gets only occasional use and then for only seconds at a time.
The DC/AC converter has more than one female socket supplying 120 Volts, and from that and an ordinary extension cord could drive the refrigerator, toaster, and microwave oven -- again much less than 1920 Watts.
If I start to overload the DC/AC converter, not very likely for my loads and a converter that can supplyk 4000 Watts, I trust that the converter will have a circuit breaker. In that case, this approach to emergency electric power should be not much more of a safety challenge than normal usage.
Note in all of this, the circuit breaker in the house does not get involved, remains ON, and waits for the utility power to come back on. Then the lights in the kitchen, front hall, etc. will come back on, and I will plug my office and kitchen loads into the wall sockets again, disconnect the DC/AC converter, put the car back in the garage, wind up the extension cords, make some notes, and f'get about the outage!
One little issue is: If the Web server computer was running when the power went out, might there be a way to have power to that computer not be interrupted all the way until the power comes back on? Yup: With some shopping, can run the server computer off another box, not very big, that has a little battery inside that can keep the computer running for a few minutes while I switch over to the DC/AC converter and again while I switch back to the utility power.
For the Hacker News audience, this is conversation is drifting into kindergarten level talk: I'm SURE Hacker News has MANY very well informed engineers on how to have un-interruptible electric power to computers in a server farm and also to the whole farm.
For more, once I wrote a math paper on detecting zero day problems, gave an invited talk at the NASDAQ headquarters, and got a tour and overview of the engineering they did for un-interruptible NASDAQ service, uh, including a remote backup server location. Such magnificent engineering has long been available.
Here I am just trying to contribute to the issue of this thread, using the engine in a car to supply standard 120 Volt A/C electric power. I'm just mentioning that for short term power outages, maybe only a few hours at a time, should be able to do okay with just a normal car and a little box that can supply 4000 Watts of 120 Volt A/C power from a 12 Volt DC battery. That's all I'm trying to do.