Toyota testing improved solar roof for EVs that can charge while driving(techcrunch.com)
techcrunch.com
Toyota testing improved solar roof for EVs that can charge while driving
https://techcrunch.com/2019/07/05/toyota-testing-improved-solar-roof-for-electric-cars-that-can-charge-while-driving/
171 comments
> The extended range is nice and all, but if somebody makes a car that can run the AC without running/draining the battery while it's parked, even if it's just a little to keep the car interior at 35°C or so, I would, without exaggeration, buy it the day it's released here.
Tesla's dog mode does this. Draining the battery isn't really something to worry about; AC uses <300 watts over long periods (turns on and off at <1 kW). Leaving it on for 8+ hours you're talking about <5% capacity loss, at a cost of <50 cents. For short trips you could leave the AC on full blast without even noticing a drop.
Tesla's dog mode does this. Draining the battery isn't really something to worry about; AC uses <300 watts over long periods (turns on and off at <1 kW). Leaving it on for 8+ hours you're talking about <5% capacity loss, at a cost of <50 cents. For short trips you could leave the AC on full blast without even noticing a drop.
It looks like the Hyundai Kona EV has a Utility Mode that works similarly (the headlights are off, the vehicle is locked in park, and you can run the AC indefinitely.)
However, based on this thread, utility mode requires the key fob, so someone could just break a window and steal the car. I wish manufacturers other than Tesla would think about these use cases:
https://www.insideevsforum.com/community/index.php?threads/u...
However, based on this thread, utility mode requires the key fob, so someone could just break a window and steal the car. I wish manufacturers other than Tesla would think about these use cases:
https://www.insideevsforum.com/community/index.php?threads/u...
It was mentioned later in that thread, but the Kona EV also lets you control the AC remotely via its mobile app without leaving the keys in the car. I don't know if it'll run indefinitely, though; my old Chevy Volt would turn off remotely started climate control after 15 minutes or so, and I haven't tried in the Kona yet.
That said, even if it is time-limited, 15 minutes is usually enough to cool down the car without leaving the AC on all day.
That said, even if it is time-limited, 15 minutes is usually enough to cool down the car without leaving the AC on all day.
Any time limit defeats the point. An electric car isn't just a car without gas, it's a climate-controlled room you can put anywhere.
As global temperatures rise, there are places becoming increasingly uncomfortable to live in. There may be cases where it's cheaper to wait out the hottest days in your car, instead of retrofitting a cooling system onto a building.
As global temperatures rise, there are places becoming increasingly uncomfortable to live in. There may be cases where it's cheaper to wait out the hottest days in your car, instead of retrofitting a cooling system onto a building.
I'm not sure how true that would be in extremely hot weather, but it is probably the only reason I'm considering a Tesla if it ever comes to my city, my commute is really short so even if it cut 200 miles off the range it'd be worth it for me.
Having a car with remote start alleviates the problem a little bit, but I'd rather not run an ICE engine while I'm not in the car for obvious reasons.
Having a car with remote start alleviates the problem a little bit, but I'd rather not run an ICE engine while I'm not in the car for obvious reasons.
Even on constant full blast with the smallest battery Tesla sells, it's only gonna use ~2-3% per hour. Over 8 hours that would be 44 miles off the 220 mile range.
> but it is probably the only reason I'm considering a Tesla if it ever comes to my city
Hmm, Telsa should be pretty reachable. Perth and El Paso look like some of the only neglected hot cities.
> but it is probably the only reason I'm considering a Tesla if it ever comes to my city
Hmm, Telsa should be pretty reachable. Perth and El Paso look like some of the only neglected hot cities.
I don't live in the US, as far as I'm aware there's only one Tesla store in my country and it's nowhere near me.
I figured- Perth is in Australia. If you're in Mexico you're pretty screwed, as is... South America, Africa, and most of Asia. You can check the map if you like!
https://www.tesla.com/findus?v=2&bounds=67.51085725091038%2C...
https://www.tesla.com/findus?v=2&bounds=67.51085725091038%2C...
Mexico. I'm actually surprised there's one charging point in my city. I'd expect there to be none.
I'm pretty hopeful that we'll either get Tesla in a couple of years or other manufacturers will come out with something.
I'm pretty hopeful that we'll either get Tesla in a couple of years or other manufacturers will come out with something.
It seems that they deliver, if I'm reading the pages right. Not sure what being further away means for servicing though.
What do you mean by 'if it ever comes to my city'?
Yeah, can't you drive Teslas anywhere?
I wouldn't want to own a car that can't be repaired locally.
Sure, I mean they float, right?
Wouldn't chucking a bucket of water over the car with the evaporation help cool the car down quicker initially? Along with least reducing the amount of time needed to run idle for cooling.
Though this would depend upon the humidity, would not work in high humidity and equally work better in low humidity.
Though this would depend upon the humidity, would not work in high humidity and equally work better in low humidity.
Sure, but for that to work you have to carry around buckets of water.
Not in the morning when you're at home.
This definitely makes Teslas more attractive to me. About half the homes on my (short) street have Teslas. I didn't know how little hot weather affected the battery usage. I had mistakenly assumed that A/C would have a greater negative impact on range.
It will on an older Leaf with a smaller battery. In Norway, you might be forced to turn of the heating in winter if traffic gets bad. But with double-digit kWh of battery capacity as a normally-unuser buffer, it won’t be much of a worry, if at all.
> Tesla's dog mode does this.
Dog mode is the main thing keeping me from trading in my Tesla for something else.
Dog mode is the main thing keeping me from trading in my Tesla for something else.
Tesla also has the milder "Cabin Overheat Protection" that can be turned on in settigns to keep the car interior from going over about 100 degrees fahrenheit.
It helps that a Tesla battery can basically power a house for several days.
2015 and later variants of the Prius already have this via the solar roof option: https://www.jpauleytoyota.com/blog/how-does-the-toyota-prius...
“If you want to activate the solar powered ventilation system before you get out of the vehicle it is a simple process. On the left side of the steering column, you will find a small square button with a car and fan on it. Press this button before you turn off your vehicle and you are all set. Next time you get in your Toyota Prius it will be nice and cool.”
Edit: apparently it’s limited to running the fan, there’s also a remote a/c option that’ll run for a few minutes off of battery before you get to the car.
“If you want to activate the solar powered ventilation system before you get out of the vehicle it is a simple process. On the left side of the steering column, you will find a small square button with a car and fan on it. Press this button before you turn off your vehicle and you are all set. Next time you get in your Toyota Prius it will be nice and cool.”
Edit: apparently it’s limited to running the fan, there’s also a remote a/c option that’ll run for a few minutes off of battery before you get to the car.
I did not know that, and neither did the salesman when I was choosing my current car. They really should put that feature front and center, at least locally. Maybe that option isn't available in this market.
The solar roof for running a fan has been around since the 2010 prius.
I had a 2010 Prius with the solar roof. It does work, but it just reduced the temperature from unbearable to quite hot, it did not make it cool. It's somewhat nice to have on very hot days, but is not really a killer feature.
Even just running the fan on a 45c day should have a huge impact on the internal temperatures of the car.
You can easily hit ~85c (+/-) in very little time then; sadly lots of children / pets are killed all the time as people are just dumb, ignorant, or forgetful.
You can easily hit ~85c (+/-) in very little time then; sadly lots of children / pets are killed all the time as people are just dumb, ignorant, or forgetful.
Someone mentioned dog mode in a Tesla, but that’s not the only feature that does this. Dog mode or Camping mode is for keeping the interior at something around 20c or whatever you set.
from reading your comment it sounds like you just don’t want the interior to ever get over 35c, which is exactly what the Cabin Overheat Protection mode is. Basically this is a set it and forget it setting that ensures the inside will never go over 100F. You can choose to use ac which kicks it on and off every so often using minimal range, or you can choose for it to only use outside ambient air, granted it if it’s 48c then you are only getting as cold as that.
check out this article and video https://insideevs.com/news/340230/how-much-does-cabin-overhe...
from reading your comment it sounds like you just don’t want the interior to ever get over 35c, which is exactly what the Cabin Overheat Protection mode is. Basically this is a set it and forget it setting that ensures the inside will never go over 100F. You can choose to use ac which kicks it on and off every so often using minimal range, or you can choose for it to only use outside ambient air, granted it if it’s 48c then you are only getting as cold as that.
check out this article and video https://insideevs.com/news/340230/how-much-does-cabin-overhe...
My old car had a sunroof that could also tilt up. That took the edge off and let excessive heat escape. Combined with a reflective windshield shade it worked reasonably well. Not chilly but more practical and env friendly than running AC for 8 hours a day.
I keep the AC on in my Tesla a lot during the summer. Costs a couple miles per hour of range. Totally worth it.
Toyota Prius had (has?) something similar. They had this add on where they install a 100W panel on the roof to run the car fan to vent outside air in and inside air out. One of my coworkers had it and the car temperature was significantly lower during the summer days during lunch.
«somebody makes a car that can run the AC without running/draining the battery while it's parked»
Temperatures could be reduced significantly with a car modification that uses very little energy: a small fan to circulate and replace all inside air with outside air, and a one-piece reflective foil cover on top of the car, covering the entire windshield + roof + sides + rear windshield.
Temperatures could be reduced significantly with a car modification that uses very little energy: a small fan to circulate and replace all inside air with outside air, and a one-piece reflective foil cover on top of the car, covering the entire windshield + roof + sides + rear windshield.
It hits these temps in Phoenix; huge market for Tesla's. They have cabin overheat protection plus you can start the AC from an app on your phone. Really nice!
A couple of the old Priuses used to have a solar powered fan.
I can’t find any good info on it at the moment but IIRC it was basically a computer fan coupled to a small solar panel so don’t think it was too effective.
https://priuschat.com/threads/solar-powered-fan-is-it-workin...
https://priuschat.com/threads/solar-powered-fan-is-it-workin...
In theory, the solar roof should absorb ~30% of the rays a cars is exposed to, so it won't heat up as much. Not sure if the effect would be significant, though.
It would help but the glass windows (greenhouse effect) are probably a bigger factor.
How does that compare the the fraction reflected by a white paint scheme?
You can have your cake, eat it and get icing on top by using a coating that
a) has a transmission window in the range that's useful for PV b) has high emissivity in the atmosphere's IR window c) has high reflectivity in the rest of the spectrum
a) has a transmission window in the range that's useful for PV b) has high emissivity in the atmosphere's IR window c) has high reflectivity in the rest of the spectrum
That’s awesome. Either we don’t have those materials nailed yet, or the demo version pictured has the cells showing for presentation purposes, or both.
Edit: third possibility described by the interesting reply below: there could be an out of visible band reflective coating over the panels.
Edit: third possibility described by the interesting reply below: there could be an out of visible band reflective coating over the panels.
Cells with such a coating would still appear dark to the human eye because the visible spectrum contains the peak of sunlight's energy distribution and you want to convert that to energy (you could optimize around the UV/violet range since the excess photon energy gets converted to heat there). But there's a broad limb of IR in the distribution that is useless because it's below the bandgap of most PV materials, that's the part you want to reflect. But then again inside the IR range there's the IR window, where you don't want to be reflective to increase emissivity to shed heat into space.
I have read research papers about such coatings, but I don't know whether they're in commercial use.
I have read research papers about such coatings, but I don't know whether they're in commercial use.
Tesla will keep your car at 105F or less while parked unless your battery is too low.
Electric car or not, a very low tech but effective approach is to use a decent sunshade. Quick to set up, and have been shown to lower the internal temperature 20 degrees or so.
I had this feature on my old 2007 Audi A6, which replaced the moon roof with a solar sun roof, which powered a fresh air fan when parked in the sun. I purchased it off-lease, and it was pretty much maxed out on features. I never saw another A6 with the solar option - I think it had to be special ordered from the factory. A shame, it was really handy in the Texas heat.
Now I have a tesla which can just run the AC at will, which is even better :)
Now I have a tesla which can just run the AC at will, which is even better :)
It would also be cool, pun intended, to add windows with liquid crystals that can darken when parked to keep additional heat out.
I've wanted this for a while, in combo with a head-tracking cabin camera. That way the windscreen would tint in specific areas over the sun, oncoming headlights, and glare.
You can't use LCs, as they don't have a real "clear" mode- they always block a very significant amount of light. You'd have to use electrochromatic paint or similar, as some trains and airplanes do. It's expensive and a chipped windscreen would be awful. You also can't get great resolution. I still wish somebody would do it.
You can't use LCs, as they don't have a real "clear" mode- they always block a very significant amount of light. You'd have to use electrochromatic paint or similar, as some trains and airplanes do. It's expensive and a chipped windscreen would be awful. You also can't get great resolution. I still wish somebody would do it.
Wouldn't darkening just absorb more heat? How about turning white, or a reflective coating? (Maybe not something liquid crystals could do, but a car with mirror shades would look cool.)
Probably true that white or reflective coating would be better, but even with black there would be much less green house effect inside the car. The windows would heat up though and would be cooled by the air outside.
I believe the reduced interior heating comes from the windows absorbing heat instead of the interior surfaces. Those hotter windows may radiate some inside, but they'll radiate a lot outside that never got into the interior.
Smart film/tint/glass on a car window: https://www.youtube.com/watch?v=c7xEcI1oSVs
Great idea! Much of this cooling can probably be accomplished by better sun shading and airflow. I always thought this[1] type of privacy glass would be a great idea in a car. Put it in park and the windows automatically tint.
http://www.smartglassinternational.com/electric-switchable-g...
http://www.smartglassinternational.com/electric-switchable-g...
> I would ... buy it the day it’s released
Sounds like this “dog mode” does exactly what you’re wanting. I see a new Tesla in your future :)
Sounds like this “dog mode” does exactly what you’re wanting. I see a new Tesla in your future :)
Electrically adjustable tint for windows would be a better option if it existed. Keep the heat out instead of dealing with it after it heats up the interior.
Just regular tint would be good too. I'm not sure if there are tints which block depending on the angle of the sun.
Just regular tint would be good too. I'm not sure if there are tints which block depending on the angle of the sun.
My gasoline Volvo has a feature where you can run the ac/heater remotely from a watch and phone app. It is limited to 15 minutes, but I find 5 minutes at full blast makes it very nice when I get in.
I believe hybrid Volvos can do this while using the battery.
I believe hybrid Volvos can do this while using the battery.
Seems like a specialised window AC unit could work, run it off solar panels on the dash board. Maybe not safe for insecure areas but a controlled work car-park .. but then you could probably just leave your windows open in 'safe' places.
Actually, in Tokyo I noticed it's common for drivers to wait for their clients for hours, sleeping in the car with the air conditioner on with the engine running, hopefully this is one step closer towards solving that issue!
[deleted]
Many modern Hybrids run the AC off battery so would it be sufficient to buy a hybrid with an app that can do "remote start" so you can turn on the car an hour before you leave work?
Just an idea but maybe you shouldn't run errands at noon anymore? Twice to the ER from running errands seems extreme.
In the meantime, maybe roll your windows down when you get in the car?
> My car's outside thermometer showed 48°C
In case you wanted to feel like you were in a blast furnace instead of an oven?
In case you wanted to feel like you were in a blast furnace instead of an oven?
how much power does an AC use (say on medium settings) ?
Wikipedia says 3kW https://en.wikipedia.org/wiki/Automobile_air_conditioning#Po...
It also says that the most efficient photovoltaics yield 175W per square meter. (Though I've seen figures as high as 200W.) https://en.wikipedia.org/wiki/Solar_panel#Efficiencies
It also says that the most efficient photovoltaics yield 175W per square meter. (Though I've seen figures as high as 200W.) https://en.wikipedia.org/wiki/Solar_panel#Efficiencies
That's for a belt-driven A/C, tied directly to the engine RPM. They're inherently much less efficient because they have to work over a wide range of speeds. A motor-driven A/C will be 1-2 kW.
That's also the peak power, and a motorized A/C will instead be turned on and off leading to a much lower power draw that also depends less on the peak power. Typically a 50-30% duty cycle, so 200-300 watts very roughly. More depending on the insulation, sun, and outside temperature.
That's also the peak power, and a motorized A/C will instead be turned on and off leading to a much lower power draw that also depends less on the peak power. Typically a 50-30% duty cycle, so 200-300 watts very roughly. More depending on the insulation, sun, and outside temperature.
And if instead of getting into a sweltering 330K car, if 300W was enough power to cool it to a reasonable 300K, that's still a win. Happy to start car to cool it down to a comfier 295K.
This man is using Kelvin... why do you use Kelvin?
yeah forget it, 3kW is small house scale
the best bet with solar panel AC... is to cover all windows with them so sunlight doesn't heat the inside of the car when parked. :cough:
the best bet with solar panel AC... is to cover all windows with them so sunlight doesn't heat the inside of the car when parked. :cough:
Window units range from 700 W to 2+ kW. The Model 3 has a pretty powerful one, at least 1 kW. That's peak draw, and it'll turn on and off intermittently[1]. Average draw should work out to 200-300 watts for medium.
[1]: Like a fridge. Refrigeration systems are most efficient at full power. IIRC it's due to the restrictor plate separating the hot and cold radiators- it's designed to work at a certain rate of flow, so you'll get gas and liquid mixing at lower power.
[1]: Like a fridge. Refrigeration systems are most efficient at full power. IIRC it's due to the restrictor plate separating the hot and cold radiators- it's designed to work at a certain rate of flow, so you'll get gas and liquid mixing at lower power.
Not sure on medium but I think ev A/C like Tesla's are 15,000 btu units. A 15k btu a/c should be between 1000-1600 watts depending on efficiency.
This probably isn't the most reliable source, but the infotainment screen on my VW estimates the hourly gas consumption for the climate system.
Running on Max A/C, the screen reads just under 1/8 gal/hr. With the A/C on and with the fans at 50%, consumption is a little less but still around 1/8 gal/hr. Consumption drops too low to get a reading when A/C is off with fans 50%.
Running on Max A/C, the screen reads just under 1/8 gal/hr. With the A/C on and with the fans at 50%, consumption is a little less but still around 1/8 gal/hr. Consumption drops too low to get a reading when A/C is off with fans 50%.
I'm actually not sure in terms of car AC. Local wisdom says that on hot days your AC will sap up to 10 HP from your engine. Not sure how accurate that is.
Looking around on Telsa forums and the like, I'm seeing numbers between 1 and 3 kW. My house's mini split AC unit draws around 9 amps (according to documentation, anyway), so around 2 kW. Actual numbers seem to be closer to 3 kW in the summer.
Looking around on Telsa forums and the like, I'm seeing numbers between 1 and 3 kW. My house's mini split AC unit draws around 9 amps (according to documentation, anyway), so around 2 kW. Actual numbers seem to be closer to 3 kW in the summer.
I currently have my Tesla plugged in to my 6kw home charger, with the AC blasting, and the range isn’t increasing, leading me to believe that the AC running 100% takes around 6kw.
hmm, gets me wondering if that's why my car can't climb hills when on AC.
"Hang on, I'm hitting the turbo button." (turns off AC)
Every car with voice control should recognize “divert life support to propulsion" as a command to turn off engine-driven AC.
Oh man passenger reactions would be so awesome. Suddenly the driver just says "divert life support to propulsion" - and the passengers are like "WAIT WHAT LIFE SUPPORT?!"
as an 80s kid you don't know how much I love your idea..
That may be part of it. Most (all?) newer cars will automatically cut off the AC pump under heavy acceleration.
Yeah I'd want that in a normal ICE car.
Why would you want this feature knowing that is burning gas that you paid for while idle? Would you be happy about the car releasing toxic gases like CO and NOX while parked?
Because of the “going to the emergency room twice with heat stroke” thing, I’d guess.
But it seems that "dying of CO poisoning while staying cool from the AC" would be worse?
Yes, and solar roof would prevent that...
Presumably you park the car outdoors when it's running, where it exhausts into the atmosphere like usual.
If the gas-powered car has a solar roof that's not a problem.
That's exactly why I want the feature of a solar roof to power AC - so I don't have to burn gas while idling and release toxic CO and NOX just to stay cool.
This comment confuses me. The electric energy isn't free, and depending on the source its possibly emitting the same gases (but hopefully at a lower rate due to efficiency gains).
I'm all for EVs but I find these types of comments distracting and underscoring a fundamental misunderstanding
I'm all for EVs but I find these types of comments distracting and underscoring a fundamental misunderstanding
Parent article is about a solar roof, parent comment wishes such a car to keep AC on while parked. Solar roof = no emissions.
Where is the misunderstanding?
Where is the misunderstanding?
You're right, misunderstanding was on my end
Does the math check out? You would need about 10kW-h to get the claimed distance, times three for the efficiency (by the way, there are NO mass-produced cells with 34% efficiency; they must be using GaAs or multijunction cells to achieve 34%) means solar input of 30kW-h per day. The projected horizontal area of a Prius is 8m^2 (including the windows) so we need about 4 hours of 1000W/m^2 insolation. Which I guess isn't totally impossible. Typical average insolation at populous latitudes is around 200W/m^2.
And then you have to figure, if you took the $ and mass budget of the solar cells, could you just make the battery pack a little bigger/better instead for the same or more gain? Keep in mind the gain would be more reliable. You wouldn't have to depend on sunny days, and sunny parking spaces.
You also have to ask if the $ spent on these solar panels might be better spent on your house, where they will never be in an indoor garage, and maybe cheaper/simpler to install.
You also have to ask if the $ spent on these solar panels might be better spent on your house, where they will never be in an indoor garage, and maybe cheaper/simpler to install.
Not everyone has a garage, or can practically run a line out to the street. A self-charging car would be a good option for many. The charge this can manage is more than I drive, i’d Be very interested.
It manages more than you can drive in ideal conditions. Sunny day, parked in the sun during the day, for probably a ton of extra cost (they are using very fancy solar cells). That might work for people who have a backup plan in arizona with unshaded parking spots available. Hopefully charging stations at apartments and city centers will continue to proliferate to make electric cars viable for more people.
My normal driving is 100 miles a month, mainly on weekends. Plus, I assume they’ll improve capacity over time. Even if it meant having to go to a public charger once in a while, it would still be a convenience.
I think 10kwh is too generous. I would think ~ 5kwh.
The Tesla model 3 is rated as 237 watt-hours/mile, but this article shows 218 wh/mi at 65mph
https://forum.abetterrouteplanner.com/blogs/entry/13-model-3...
Using that exact figure would require 6kwh, and driving slower would require less.
The Tesla model 3 is rated as 237 watt-hours/mile, but this article shows 218 wh/mi at 65mph
https://forum.abetterrouteplanner.com/blogs/entry/13-model-3...
Using that exact figure would require 6kwh, and driving slower would require less.
Yes looks like GaAs: https://global.toyota/en/newsroom/corporate/28787347.html
If they can bring the cost down on that, for other types of panel manufacturing for non automotive markets, that would be pretty amazing. 22% monocrystalline silicon 156mm cells are a commodity now (such as to build a 60 or 72 cells panel with and sell it under $0.60/watt), but 30 to 34% GaAs cells are incredibly expensive.
Until very recently GaAs triple junction cells have been so costly they are only used on satellites and other spacecraft.
Until very recently GaAs triple junction cells have been so costly they are only used on satellites and other spacecraft.
If they can make them as cheap as silicon then obviously people will buy them instead, but it's not clear to me that panel efficiency is a relevant factor in the economics of commercial solar power.
Interestingly it is, but more because of the associated costs. Extra panel efficiency means you need less land, less mounting hardware, and fewer installers for the same power solar farm.
Perovskite solar panels are entering commercialisation at the moment, they will get 30% efficiency and above within the next few years.
They are claiming up to 27.7mi per day left in the sun. If true, my 5mi commute each way would be possible without ever charging the vehicle in the summer...
That being s said, curious how this holds up to weather (hail, snow, etc) and whether those numbers are accurate.
That being s said, curious how this holds up to weather (hail, snow, etc) and whether those numbers are accurate.
Given the small surface area of the roofs, the efficiency of existing solar panels, and how much car companies exaggerate when it comes to miles (do they mean 27.7mi with all the seats removed, etc.) I would expect it to be a practical no-go for anything except sunshine.
I'm from michigan, so in the winter assuming you park your car in the open for your job, you can easily expect it to be covered in snow - whenever it snows - which is all winter.
So it'd only be beneficial here during the summer, except when it's raining which is currently 3/7 days of the week.
I mean it'd be a nice bonus I guess, but at least for my situation it wouldn't make a ton of sense to spend extra on.
I'm from michigan, so in the winter assuming you park your car in the open for your job, you can easily expect it to be covered in snow - whenever it snows - which is all winter.
So it'd only be beneficial here during the summer, except when it's raining which is currently 3/7 days of the week.
I mean it'd be a nice bonus I guess, but at least for my situation it wouldn't make a ton of sense to spend extra on.
It would be very climate dependent.
Here in Texas, typically I'd have 0 to 5 days per year with snow on my car. And nobody drives on those days anyway.
And there are 228 sunny days in an average year.
I would be worried about hail, though. I know a lot of people whose cars have been damaged or even totalled by hail.
Here in Texas, typically I'd have 0 to 5 days per year with snow on my car. And nobody drives on those days anyway.
And there are 228 sunny days in an average year.
I would be worried about hail, though. I know a lot of people whose cars have been damaged or even totalled by hail.
Insurance companies here have worked out that they save money by cloud seeding outside of the cities to minimize hail damage in more populated areas.
If true, my 5mi commute each way would be possible without ever charging the vehicle in the summer
If you're interested in reducing environmental impact, a bicycle would also let you do that commute without charging and with much less environmental impact than an EV covered in solar cells... though it may be less pleasant in hail and/or snow.
If you're just interested in saving money for electricity, then I'd be surprised if the extra cost in adding all of those solar cells is cheaper than paying for the electricity.
If you're interested in reducing environmental impact, a bicycle would also let you do that commute without charging and with much less environmental impact than an EV covered in solar cells... though it may be less pleasant in hail and/or snow.
If you're just interested in saving money for electricity, then I'd be surprised if the extra cost in adding all of those solar cells is cheaper than paying for the electricity.
I think it will make a lot of sense for light vans. A lot more surface.
It's probably going to fluctuate quite a bit. But for a lot of people on average they'd find their car charged of nearly charged when it's been sitting out there for hours/days. The exception would be longer trips, which most people don't do every day.
The one exception is parking. This isn't as useful if you use covered parking. And with a new car I'd rather use covered parking.
This is like any other concept car. It's a cool concept but won't make it to production.
The commercial viability of this is far off. 34% solar is prohibitively expensive. You won't see these on cars until costs come down significantly.
The commercial viability of this is far off. 34% solar is prohibitively expensive. You won't see these on cars until costs come down significantly.
I thought the same about defect free LCD panels. Now they are cheap enough to make a house out of them and they have replaced billboards that used to be made from paper.
One thing that has changed is the structural value of the roof of a car. In the olden days the roof was a vital part of the safety cell. Now it is not quite the same. The A-pillar has been toughened up and the engineering for the roof is different, hence the all-glass affair on the Tesla Model 3 and other marques.
Elon Musk said there was no point in having solar panels on the car and that those would be best kept roadside for generating power that goes into the grid.
He was right.
But you are not going to persuade your supermarket to cover their entire parking lot with solar cells so your car can park in the cool shade underneath them whilst getting free power.
If solar cells can be as good as printed and be an integral plart of a car in the place of steel, paint, glass or carbon-fibre then they don't have to make commercial sense in the rational way that Elon Musk outlines. When I get my EV campervan in 2025 I hope the roof is festooned with solar panels that are not some bolt on but integrated into the design. If I am parked up somewhere and they give me enough power to make myself a cup of tea and power my laptop then I would be happy with that. If they were a $5K option then they would also be a $3K add-on to the resale value of the campervan. If I kept the van for ten years then $200 a year for that month of use I get out of the van might be more expensive than supercharging the EV for pennies but I would still just like having such a space age feature.
Nothing really makes sense with autos. There isn't such a thing as a stripped down utilitarian auto. It is all a matter of degree. Some people pay for carbon-fibre cup holders. Or fake carbon fibre hood scoops. Or extra titanium bits for the exhaust. Or, perhaps more relevant, a cabriolet top that retracts at the touch of a button at speeds up to 25 mph. If that makes sense to people - and it does - then solar cells on the bonnet and roof can easily be foisted onto the marketplace.
One thing that has changed is the structural value of the roof of a car. In the olden days the roof was a vital part of the safety cell. Now it is not quite the same. The A-pillar has been toughened up and the engineering for the roof is different, hence the all-glass affair on the Tesla Model 3 and other marques.
Elon Musk said there was no point in having solar panels on the car and that those would be best kept roadside for generating power that goes into the grid.
He was right.
But you are not going to persuade your supermarket to cover their entire parking lot with solar cells so your car can park in the cool shade underneath them whilst getting free power.
If solar cells can be as good as printed and be an integral plart of a car in the place of steel, paint, glass or carbon-fibre then they don't have to make commercial sense in the rational way that Elon Musk outlines. When I get my EV campervan in 2025 I hope the roof is festooned with solar panels that are not some bolt on but integrated into the design. If I am parked up somewhere and they give me enough power to make myself a cup of tea and power my laptop then I would be happy with that. If they were a $5K option then they would also be a $3K add-on to the resale value of the campervan. If I kept the van for ten years then $200 a year for that month of use I get out of the van might be more expensive than supercharging the EV for pennies but I would still just like having such a space age feature.
Nothing really makes sense with autos. There isn't such a thing as a stripped down utilitarian auto. It is all a matter of degree. Some people pay for carbon-fibre cup holders. Or fake carbon fibre hood scoops. Or extra titanium bits for the exhaust. Or, perhaps more relevant, a cabriolet top that retracts at the touch of a button at speeds up to 25 mph. If that makes sense to people - and it does - then solar cells on the bonnet and roof can easily be foisted onto the marketplace.
Covering an entire Prius with exotic semiconductors is not the road to brisk sales.
They covered the car, including the back window, in triple-junction solar cells. Last I heard, those were made of expensive stuff like indium gallium arsenide junctions. They were popular on satellites because they do really really well outside of atmosphere and much worse in shaded and indirect light conditions than silicon.
I'd like to know how much those cells really cost and how much power is left when you can see out the back window again. 860W sounds like a high number. Fancy 30+% triple junction solar cells cost something like $200-$300 per _watt_ years ago. As a result, those solar panels might be worth more than the car itself! Even if they've got the fancy ones down to $50/watt, that's still $43000 in solar cells. Sure they've got grandiose claims about how little they'll cost in the future, but I'd like to know about today.
This is same bunk as hearing they've made a new crazy high efficiency solar cell, but it can't be manufactured outside a lab with a mountain of grad students doing the work. Sounds cool, but it won't come to market any time soon.
I'd like to know how much those cells really cost and how much power is left when you can see out the back window again. 860W sounds like a high number. Fancy 30+% triple junction solar cells cost something like $200-$300 per _watt_ years ago. As a result, those solar panels might be worth more than the car itself! Even if they've got the fancy ones down to $50/watt, that's still $43000 in solar cells. Sure they've got grandiose claims about how little they'll cost in the future, but I'd like to know about today.
This is same bunk as hearing they've made a new crazy high efficiency solar cell, but it can't be manufactured outside a lab with a mountain of grad students doing the work. Sounds cool, but it won't come to market any time soon.
I will literally believe somebody has successfully commercialized triple junction GaAs cells, when I can pull out my Visa card and order a pallet of 20 assembled modules from a distributor. As I can do now for 54, 60 and 72 cell panels built from high quality 156mm monocrystalline Si cells.
Until then I think triple junction GaAs is going to see the most use in experimental UAVs funded by research money, and satellites.
Until then I think triple junction GaAs is going to see the most use in experimental UAVs funded by research money, and satellites.
See also: https://lightyear.one/
https://en.wikipedia.org/wiki/List_of_cities_by_sunshine_dur...
Using those I found Lightyear quotes "271 days of carefree range" for Marsa Alam, Egypt. Interested if anyone finds a city with a higher quote
https://en.wikipedia.org/wiki/List_of_cities_by_sunshine_dur...
Using those I found Lightyear quotes "271 days of carefree range" for Marsa Alam, Egypt. Interested if anyone finds a city with a higher quote
We used to fight for the shady parking spots.
Imagine the future when you fight for the sunny ones.
Imagine the future when you fight for the sunny ones.
This is interesting because the solar strip on the Nissan Leaf SL was just a do hickey, 9 watts max. It was capable of trickle charging the 12V starter which meant less draw for charging the 12V coming from the traction battery. Not nothing but really not much. I don't think it even rounded up to a mile of range.
I'm not sure what's up with the visibility out the rear window of the Honda as pictured.
I'm not sure what's up with the visibility out the rear window of the Honda as pictured.
> It was capable of trickle charging the 12V starter
Enough to increase the utility of a rarely driven ICE car tenfold.
Enough to increase the utility of a rarely driven ICE car tenfold.
I once used an 85W portable solar panel to charge my battery while driving after the alternator failed.
It was surprisingly effective at keeping the car operable, at least until the sun went down. I didn't have any accessories running, so it was just the ECU/fuel pump/injectors/ignition it had to keep up with.
The experience left me wondering what MPG improvement it would be to embed solar cells in the trunk lid and hood for charging the battery in the daytime, offloading the alternator.
It was surprisingly effective at keeping the car operable, at least until the sun went down. I didn't have any accessories running, so it was just the ECU/fuel pump/injectors/ignition it had to keep up with.
The experience left me wondering what MPG improvement it would be to embed solar cells in the trunk lid and hood for charging the battery in the daytime, offloading the alternator.
Triple junction GaAs based panels for a whole 860 watts of power in full sun at the right angle, no mention of cost.
Anybody know how much a panel like that goes for per watt now days?
Anybody know how much a panel like that goes for per watt now days?
I've never seen triple junction GaAs raw cells sell for less than $6/watt stc rating.
For comparison I can buy pallet loads of 72 cell, 370W panels built from high efficiency mono Si cells for under $0.55/watt stc.
For comparison I can buy pallet loads of 72 cell, 370W panels built from high efficiency mono Si cells for under $0.55/watt stc.
Doesn't answer your question but I just saw that you can get ordinary 100W panels for 65€ on eBay now (in pack of 2)!
Meanwhile I just discharged 12V battery of my hybrid toyota by sitting inside with phone plugged in and fans running.
There was no warning and now I have to fiddle with cables and second car to get my car to start. All while there's still charge in hybrid batteries that I assume could trickle charge my 12V to help me start the car. But it won't.
There was no warning and now I have to fiddle with cables and second car to get my car to start. All while there's still charge in hybrid batteries that I assume could trickle charge my 12V to help me start the car. But it won't.
There's also Sono Motors, a start-up from Munich, Germany. They aim at delivering something they call a SEV (Solar Electric Vehicle) in 2020. They have an interesting concept and more than 10k reservations. https://sonomotors.com/?lang=en
Thanks for sharing the Sono Motors link.
The Sion model is to be available in 2021 (or at least that is what I read on their website.)
I like this practical little car with energy interface considerations at its core. Solar body panels can add up to 34km range per day, this seems to be a major incremental improvement to the EV model, I think.
Sticker price of 25.5k Euro (16k for base and est. 9.5k for battery) and they let you buy the battery separately or you can lease one. It seems it will be manufactured in Sweden (Trollhättan). I want to learn more about their (export) US market strategy. Needless to say I do like this SEV concept.
Sticker price of 25.5k Euro (16k for base and est. 9.5k for battery) and they let you buy the battery separately or you can lease one. It seems it will be manufactured in Sweden (Trollhättan). I want to learn more about their (export) US market strategy. Needless to say I do like this SEV concept.
> The Sion model is to be available in 2021 (or at least that is what I read on their website.)
2021 will probably be more realistic for delivery. Though they say in their FAQ that they will start production in the second half of 2020.
2021 will probably be more realistic for delivery. Though they say in their FAQ that they will start production in the second half of 2020.
I wonder if there is a market for a car cover that acts like a flexible solar blanket. Here in Texas it could offer your vehicle some protection from the Sun while charging it at the same time.
it'd be a great way to donate solar panels to local teens
Always wanted this, makes a lot of sense in the desert. Is Toyota still turning on the headlights in the daytime? Seems like it would negate this advancement.
You mean DRL's? They lead to a significant reduction in crash rate - and since much of a car's carbon impact is tied up in the manufacturing of the car, that is likely a far greater impact than running the DRL's all day.
Plus, with LED DRL's becoming more common, the power drain is much less significant than the old incandescent lights. My old car ran the 55W headlights at around 40W each for DRL's. My new car has a DRL LED module that uses around 3W.
Plus, with LED DRL's becoming more common, the power drain is much less significant than the old incandescent lights. My old car ran the 55W headlights at around 40W each for DRL's. My new car has a DRL LED module that uses around 3W.
No, the headlights were unable to be turned off on a friend’s old carolla. Was a while ago though.
That sounds like DRLs... In some cars they use the headlights at reduced power as DRLs.
How'd you figure out the draw from your various headlights? Bulb specs?
I measured it once, kept reading about how OEM wiring was under spec'ed and led to voltage drop at the headlight, so I measured the voltage + current, and got a bit over the 55W rating for the regular headlight.
After the first measurement I thought I proved that the wiring was seriously undervolting the headlights when I only measured around 10V (and just under 40W), then I realized that was the DRL's.
To find the 3W spec for the LED DRLs on my current car, I just looked up the specs on an replacement module - I don't crawl around the hood with a multimeter anymore, too much expensive stuff in the way.
(the reason I measured in the first place was because I wanted brighter headlights since I was doing a lot of night driving in mountain roads, and thought that replacing the wiring harness would be an easy upgrade. I ended up adding a set of driving lights which looked kind of dorky, but worked great)
After the first measurement I thought I proved that the wiring was seriously undervolting the headlights when I only measured around 10V (and just under 40W), then I realized that was the DRL's.
To find the 3W spec for the LED DRLs on my current car, I just looked up the specs on an replacement module - I don't crawl around the hood with a multimeter anymore, too much expensive stuff in the way.
(the reason I measured in the first place was because I wanted brighter headlights since I was doing a lot of night driving in mountain roads, and thought that replacing the wiring harness would be an easy upgrade. I ended up adding a set of driving lights which looked kind of dorky, but worked great)
Without clicking, I was going to post a sarcastic comment about also putting battery on hood and trunk lid. Then I saw the picture. lol
The solar one of worked meant I do not have to charge the car for most of the trips I did!!! Shocking.
There’s no way it’ll charge while driving. It might discharge more slowly while driving and charge while parked.
mtgx(2)
If you run the math on this, even assuming 100% efficient conversion to electricity, it doesn't seem very useful.
>>The new system will provide up to 44.5 km (27.7 miles) of additional range per day while parked and soaking up sun, and can add up to 56.3 km (35 miles) of power to both the driving system and the auxiliary power battery on board, which runs the AC, navigation and more.
As someone with nearly 100 miles of round trip commute (and who parks in a usually very sunny parking lot) I would certainly appreciate 27+ miles of "free" range. Certainly enough to be useful for me. In the case of a Tesla I'm sure it's more than enough to negate the continuous usage of sentry mode as well.
As someone with nearly 100 miles of round trip commute (and who parks in a usually very sunny parking lot) I would certainly appreciate 27+ miles of "free" range. Certainly enough to be useful for me. In the case of a Tesla I'm sure it's more than enough to negate the continuous usage of sentry mode as well.
I wonder if it'll provide enough power so that you can park and wait with AC or the stereo (admittedly two very different loads) running without worrying about it cutting into your range.
I think that would wholely depend on the setup for the AC compressor. If it's entirely electric and sized appropriately it can be a fairly efficient mechanism. A friend of mine uses the AC in their tesla to keep pastries cold from lunch to evening commute for < 10-20 miles of range depending on ambient temperatures. Meanwhile my gas SUV idles at .3 - .5 gallons per hour depending on engine load. (4 cylinder 2.0 liter, non-turbo).
They use their Tesla like a fridge for only 10-20 miles reduction????? That's amazing both in it's apparent wastefulness and efficiency. If that's the same scale, solar charging could easily keep your AC and stereo on while you wait.
I believe they just set the cooling to around 64F to keep pastries from melting etc. First world problems for sure.
At least they aren't burning liquid dinosaur.
Ultimately depends on how they're charging their Tesla. Could be gasified or petrified dinosaur!
> The new system will provide up to 44.5 km (27.7 miles) of additional range per day while parked and soaking up sun
That seems like a big deal. Most drivers actually drive in the 30-50 mile range per day (IIRC Chevy said that over 80% of commuters would be able to only be on electric with their 53-electric-mile-range Volt). So for most drivers this amount of power could reduce their external electricity needs by somewhere between 50-100%.
That seems like a big deal. Most drivers actually drive in the 30-50 mile range per day (IIRC Chevy said that over 80% of commuters would be able to only be on electric with their 53-electric-mile-range Volt). So for most drivers this amount of power could reduce their external electricity needs by somewhere between 50-100%.
Who wrote this?
"This demo car’s prototype cells can convert solar energy at 34% and up"
34% what?
"Using a redesigned solar battery cell film that measures only 0.03 mm"
0.03mm wide? Long? And what's a solar battery cell film???
"This demo car’s prototype cells can convert solar energy at 34% and up"
34% what?
"Using a redesigned solar battery cell film that measures only 0.03 mm"
0.03mm wide? Long? And what's a solar battery cell film???
The efficiency percentage on a solar panel refers to the amount of radiated energy from sunlight that can be converted into electricity. https://en.m.wikipedia.org/wiki/Solar_cell_efficiency
Less sure about the 0.03mm but I'm guessing the relevant metric would be thickness or depth.
Less sure about the 0.03mm but I'm guessing the relevant metric would be thickness or depth.
A quarter to half the thickness of a strand of human hair? That seems like an insane innovation (and difficult to produce/keep reliable in the field).
https://en.m.wikipedia.org/wiki/Thin-film_solar_cell
This does seem to be the case. It's embedded in a laminate.
This does seem to be the case. It's embedded in a laminate.
I know that, its sloppy writing not to state it though.
Kind of an asinine comment then. Presumably anyone reading that article would know about efficiency.
If you want to take that approach to journalism they could have cut down the length by about 90%, they cud prbly ms ut mst ltrs frm wrds nd yd stl no wht ws sed.
And I still don't know what a solar battery cell film is.
And I still don't know what a solar battery cell film is.
https://en.m.wikipedia.org/wiki/Thin-film_solar_cell
I think you're being a bit performative with your greivance! Took a few seconds of Googling :-)
I think you're being a bit performative with your greivance! Took a few seconds of Googling :-)
Performative maybe, but I made my point.
I searched for battery on that page so this isn't the fabled solar battery cell film.
I searched for battery on that page so this isn't the fabled solar battery cell film.
The extended range is nice and all, but if somebody makes a car that can run the AC without running/draining the battery while it's parked, even if it's just a little to keep the car interior at 35°C or so, I would, without exaggeration, buy it the day it's released here. Hell, I'd consider it even if it would just keep the fans on to vent the hot air out.
Parking in the sun while doing errands, which often involve multiple short trips where the car's AC doesn't get enough time to cool it down, seems to be a very common cause of heat-stroke among white-collar workers here. I've had to go to the ER twice about it this summer alone.