Milwaukee M18 Battery Reverse Engineering(quagmirerepair.com)
quagmirerepair.com
Milwaukee M18 Battery Reverse Engineering
https://quagmirerepair.com/milwaukee-m18-battery-reverse-engineering
105 comments
FWIW I find these batteries and the charger to be exceptional. You can just leave batteries in and it knows when to stop charging. If you get the big charger and put a bunch of batteries in it charges them round-robin style. And the batteries themselves seem to be sturdy, robust, and high capacity. They're also expensive af so you want to wait for a sale if possible. I even spent a ridiculous amount of money on the battery-powered wet/dry vac and haven't regretted it for a moment.
> You can just leave batteries in and it knows when to stop charging.
This is true of all modern lithium ion consumer hardware, because if you don't get this part right, the battery explodes and burns down your house the first time.
This is true of all modern lithium ion consumer hardware, because if you don't get this part right, the battery explodes and burns down your house the first time.
One of my co workers decided to charge his drone at the office and found this out . Or more accurately the whole office did
The DJI batteries and charger are very clever too. The batteries auto discharge to a safe level after 2 weeks on the shelf
Is there now a section of the employee policies that forbids charging drones in the office?
The manuals have always told people to charge outside, for this reason.
Not when the charger says "for home and office use only"
There's probably some weird clause in the usage guidelines saying you need to have the charger attended all times it is plugged in or something like that.
It's not just a clause. People will claim that this is the only safe way to charge them.
Personally, I think we need a cultural-architectural accommodation - we used to have coal chutes, milkman boxes, ice doors. For well-regulated but large batteries like an EV, a detached garage. For raw cells, a grill sitting on the driveway.
I have only had one "Spicy Pillow" from consumer devices (a phone-charger power bank), but with raw LIPOs in RC hobby gear it was an eventuality.
Personally, I think we need a cultural-architectural accommodation - we used to have coal chutes, milkman boxes, ice doors. For well-regulated but large batteries like an EV, a detached garage. For raw cells, a grill sitting on the driveway.
I have only had one "Spicy Pillow" from consumer devices (a phone-charger power bank), but with raw LIPOs in RC hobby gear it was an eventuality.
I just switched over the last 6 months over to Milwaukee tools for my home DIY stuff and they are really exceptional. I got one of the 7 1/4" circular saws with a FORGE battery and it just cuts everything I've thrown at it effortlessly. I'd put it as more powerful than my Dewalt 10" corded tablesaw, at least it seems much happier to rip a 2x4 than the table saw. I even designed a 3D printed sled for it to run on my track saw tracks and it does a great job there.
Some of the battery powered tools really are more powerful these days, since a home 110v circuit is limited to a total draw of 1800w or so. The latest gen 18v/24v batteries can actually deliver more than that, at least for short bursts. Especially the big 4AH+ packs.
I recently purchased a M18 trimmer after not using one for years, it still surprises me that when not on the throttle - "off" is truly off, and not the persistent hum of a 2 stroke that is too loud in your left ear. No fumes and no fuel/oil mix to worry about.
I've tried to minimize the number of battery families I have, but I did buy into the Ego set of tools ~10 years ago for the yard tools, starting with the mower but I've since added the trimmer and chainsaw. Not having to do small motor repair and maintenance has been so nice!
I was a little annoyed that some of the Milwaukee tools require you to go with the M12 battery (the "bandfile" is what sucked me in) so now I've got 2 battery ecosystems for the tools, but I guess that's not the end of the world.
I was a little annoyed that some of the Milwaukee tools require you to go with the M12 battery (the "bandfile" is what sucked me in) so now I've got 2 battery ecosystems for the tools, but I guess that's not the end of the world.
Even TTI’s lesser Ryobi stuff (my usual go to as a DIYer who bought two tools 15 years ago and the batteries are still compatible) has benefited immensely from tabless and 21700 cells. My 21700 8aH batteries is usually the difference between “can’t cut” and “huh is slowed a little <shrug>”
I think the Ryobi are a good choice. ~12 years ago I got Porter Cable tools, and they worked very well for me over that time. But there was a pretty limited set of tools available, it did cover the core ones though. I had previously had DeWalt tools and felt I didn't use them up to their potential, so I went "down" to the Porter Cable.
I almost went with Ryobi when I did my recent refresh. But I've changed to doing way, way more with the tools, I'm basically using them every weekend now. And the Milwaukees are just a joy to use, though you do pay for that. One benefit I didn't realize when I bought the hammer drill: It will detect if it grabs and the tool starts spinning. I was using a mini auger to break up some soil and the Porter Cable I nearly broke my wrist when it grabbed. I got the Milwaukee partly because it had a second handle you could add, but the accelerometer worked even better than that.
I almost went with Ryobi when I did my recent refresh. But I've changed to doing way, way more with the tools, I'm basically using them every weekend now. And the Milwaukees are just a joy to use, though you do pay for that. One benefit I didn't realize when I bought the hammer drill: It will detect if it grabs and the tool starts spinning. I was using a mini auger to break up some soil and the Porter Cable I nearly broke my wrist when it grabbed. I got the Milwaukee partly because it had a second handle you could add, but the accelerometer worked even better than that.
I never buy the batteries - I always look for a tool with the battery, as you can almost always score a free tool (or free battery depending on how you look at it).
The 4x 18V/5Ah batteries that came with my lawnmower (which uses them in pairs) are retailing for for $560.
And then not as any sort of special deal, just the standard retail bundle, the lawnmower with four batteries included costs $700. So that's $560 of batteries and $140 of lawnmower.
It's funny how lithium ion cell prices have absolutely cratered everywhere else, but the price of tool batteries just keeps going up.
I wish there was somebody making reputable quality compatible tool batteries instead of mystery brand counterfeit trash.
And then not as any sort of special deal, just the standard retail bundle, the lawnmower with four batteries included costs $700. So that's $560 of batteries and $140 of lawnmower.
It's funny how lithium ion cell prices have absolutely cratered everywhere else, but the price of tool batteries just keeps going up.
I wish there was somebody making reputable quality compatible tool batteries instead of mystery brand counterfeit trash.
You get what you pay for.
Tool batteries as a general rule don't do anything fancy internally, so they are easily substituted. I suspect it's mostly a matter of the main buyers being tradies/workers who use them to make money and thus don't care that much about the expense of the batteries - they probably aren't replaced that often.
Would be nice if there was a 3rd-party seller known to use quality cells though, rather than unknown off brands.
Tool batteries as a general rule don't do anything fancy internally, so they are easily substituted. I suspect it's mostly a matter of the main buyers being tradies/workers who use them to make money and thus don't care that much about the expense of the batteries - they probably aren't replaced that often.
Would be nice if there was a 3rd-party seller known to use quality cells though, rather than unknown off brands.
Curiously, the mystery brand Bosch-compatible batteries on I bought on eBay -- literally cheapest seller -- seem to work very well even after years.
With brandless batteries, it's luck-of-the-draw, but overall, as much as I do wish there were some way to know what you're getting, I've had good luck more often than not.
What's also been nice is the rise of adapters. My Bosch blue batteries now fit many places they didn't used to.
With brandless batteries, it's luck-of-the-draw, but overall, as much as I do wish there were some way to know what you're getting, I've had good luck more often than not.
What's also been nice is the rise of adapters. My Bosch blue batteries now fit many places they didn't used to.
I wish these manufacturers wouldn't go brandless, because I've found some cheap but great laptop chargers in the past that I would buy a ton of if I knew who made them, but the brandless nature means that once that seller is done or out of stock, it's back to crapshoot.
Some of these brandless Chinese makes are really solid, high quality products, but you can't easily tell which ones because they're visually indistinguishable from the bad ones.
Some of these brandless Chinese makes are really solid, high quality products, but you can't easily tell which ones because they're visually indistinguishable from the bad ones.
At this point I suspect the only way we're getting compatible tool batteries is if the E.U. comes out with regulation.
No company actually wants to make it easier for people to buy other tool brands.
No company actually wants to make it easier for people to buy other tool brands.
Before the EU can do that, someone will have to define a standard.
That is how the EU will do that.
That's not how literally anything works, or has ever worked.
> It's funny how lithium ion cell prices have absolutely cratered everywhere else, but the price of tool batteries just keeps going up.
Seems like the tool batteries might be the new ink cartridges.
Seems like the tool batteries might be the new ink cartridges.
ceenr.com batteries appear to be ok.
Behold
https://ceenr.com/ !
https://ceenr.com/ !
Seems like this is the kind of thing that could be the basis of a community?
It feels like there is a segment the tool co's are selling toward, that leaves another segment underserved.
Eip if this is something you want to hobby-horse on.
It feels like there is a segment the tool co's are selling toward, that leaves another segment underserved.
Eip if this is something you want to hobby-horse on.
Drug dealers give out feelers to get customers started.
Indeed, I've been really pleased. They continue to hold a solid charge for years as well, even when left in harsh environments (like fluctuations between extreme hot and cold, etc). When I first started using battery power tools they were terrible. They had almost no power and batteries would die rapidly, usually at the worst possible time (like when you're using arms, shoulders, and knees to hold a piece in place and you just need to get a couple of screws in to hold it in position and the damn thing dies). A few years ago my wife got me a Milwaukee power driver/drill set and it almost instantly became my favorite tool. I haven't switched to the saws yet because I have great saws that stay in my shop, but I'm impressed enough that if I need to go to a work site again I'll consider it very seriously, whereas in the past I never would have.
Hell yeah. I bought the Milwaukee shop vac a few weeks ago. Didn't realize it comes without batteries... which come without a charger. But I couldn't be happier with it. We have a cat that will create mounds - tall mounds - of cat litter in front of the litterbox entrance. Just hurls it out the hole somehow into a big pile. I just empty out the big tray at the bottom of the shop vac, suck up the litter in a few seconds, and dump it right back into the box. It's quick, clean, and easier than trying to change a cat's behavior. And for cat barves, like when they eat too fast, I just take the filter out and vacuum that up no problem, and it's powerful enough that you can't even tell that anything happened on the rug. (It's always on a rug, never on the hardwood floor. Naturally.) It's a game changer for this cat owner.
They're not the only battery tools I have (also have some Makita), but I am a big fan of virtually all my M12/M18 stuff. From the track saw, to the portable bandsaws, to the band files, oscillating multitools, reciprocating saws, jigsaws, drills, drivers, blowers, string trimmers, etc... their lineup is just incredibly diverse, servicing many trades/tasks, and they hardly ever make a 'dud'.
Their batteries, at least in my experience, have also been similarly long-lived and reliable over years. And yeah - like some others have said - I also get all my batteries from 'battery included' tools/deals. I don't think I've ever bought one by itself.
Their batteries, at least in my experience, have also been similarly long-lived and reliable over years. And yeah - like some others have said - I also get all my batteries from 'battery included' tools/deals. I don't think I've ever bought one by itself.
I have three M18 batteries that are from 2011, and have outlasted 4 Ryobi batteries that get much less abuse.
Define abuse — because what Lithium Ion hates more than anything is long periods stored at over 80 percent, and especially heat stress while fully charged.
Batteries which are used regularly and spend more time between 20–80 percent full might be less "abused" than batteries which are used infrequently, and stored in a room which sometimes gets hot.
Batteries which are used regularly and spend more time between 20–80 percent full might be less "abused" than batteries which are used infrequently, and stored in a room which sometimes gets hot.
I’d say the thing any lithium seems hate worse, for me, are long periods at 0%.
As a homeowner I’ve had Ryobi lithium batteries for over a decade. Other than having added a couple battery packs from deals and a couple batteries from tools, I’ve not had a single one of my batteries fail. All are being stored at the maximum charge. Some don’t last quite as long these days, to be expected with age, but not one has actually failed even from being dropped off ladders onto concrete. I did, however, have a Dewalt at work that died from falling 4 feet to the carpet floor. I’ve only had one Ryobi tool fail in that time, and those circumstances were questionable since someone had borrowed it.
Experiences are localized and subjective.
As a homeowner I’ve had Ryobi lithium batteries for over a decade. Other than having added a couple battery packs from deals and a couple batteries from tools, I’ve not had a single one of my batteries fail. All are being stored at the maximum charge. Some don’t last quite as long these days, to be expected with age, but not one has actually failed even from being dropped off ladders onto concrete. I did, however, have a Dewalt at work that died from falling 4 feet to the carpet floor. I’ve only had one Ryobi tool fail in that time, and those circumstances were questionable since someone had borrowed it.
Experiences are localized and subjective.
True 0V is very bad for lithium batteries, but extended periods at low SoC should be Ok (2.5V+). If there's any drain on the battery though low SoC can easily become 0V and dead battery (most chargers should refuse to charge those)
Same with my blue Bosch batteries from 2010. They use quality cells
Where do you usually look for a sale on Milwaukee? I got lucky finding a great bundle sale at a Home Depot once, I'd love any tips on where/when to look more specifically.
Home Depot is usually pretty good. Bundles are available fairly commonly as starter packs if you need to start from nothing. The drill/impact kit is likely where I'd begin since both of those (gen3) are exceptional in my opinion.
Where it gets fun are the "buy a battery pack and get a tool free" deals. I had a bunch of text typing this out, but the stickied Reddit post covers it better[1]. You can typically get the tool you want for 40-60% off when/if it goes on sale using the "Home Depot Hack". Most common tools do at least once a year - the esoteric items are more hit or miss.
I rarely pick up a tool now at full price. Once I know I want one, I simply add it to a list and note when it goes on sale in one of those combo deals. I've also picked up way more batteries than I ever will need due to other sales as well.
The Milwaukee "buy more save more" event also works well if you need what is going on sale at the time.
Reddit /r/milwaukeetool is a good place to check in from time to time for sales. Slickdeals is great for setting up an alert, but the exceptional deals get sold out quickly once it hits that site. There are also Discord groups out there as well if you go deep down the rabbit hole.
Warning: Once you learn about Packout this becomes somewhat of an addiction for certain personalities.
[0] https://old.reddit.com/r/MilwaukeeTool/comments/1gwhvi9/the_...
Where it gets fun are the "buy a battery pack and get a tool free" deals. I had a bunch of text typing this out, but the stickied Reddit post covers it better[1]. You can typically get the tool you want for 40-60% off when/if it goes on sale using the "Home Depot Hack". Most common tools do at least once a year - the esoteric items are more hit or miss.
I rarely pick up a tool now at full price. Once I know I want one, I simply add it to a list and note when it goes on sale in one of those combo deals. I've also picked up way more batteries than I ever will need due to other sales as well.
The Milwaukee "buy more save more" event also works well if you need what is going on sale at the time.
Reddit /r/milwaukeetool is a good place to check in from time to time for sales. Slickdeals is great for setting up an alert, but the exceptional deals get sold out quickly once it hits that site. There are also Discord groups out there as well if you go deep down the rabbit hole.
Warning: Once you learn about Packout this becomes somewhat of an addiction for certain personalities.
[0] https://old.reddit.com/r/MilwaukeeTool/comments/1gwhvi9/the_...
HomeDepot is one of the few warranty retailers. The “Special Buy of the Day” is updated a few minutes after midnight and usually has power tools about 10% of the days or the year. Right now HD is running their “Black Friday of Spring”. Some of the best deals for hand tools are in-store clearance, so you just have to be in the store and find it (SlickDeals will try to announce those, but inventory for those are store-specific).
Sadly one of the best ways to get cheap Milwaukee M18 tools is the “hackable” sales from Home Depot: when 2 SKUs bought together makes them both cheaper, but if you buy them online and have the 2 SKUs sent to different HomeDepo stores, you can cancel one of the SKUs later and the non-cancelled one is deeply discounted. It’s probably a violation of ToS, but customer service reps allow it and support it, so maybe it’s not actually a violation… ? It feels like corporate may eventually ban users who abuse that and cost more money than they are worth.
Milwaukee doesn’t sell via Amazon or eBay and there are notoriously good Chinese clones on those sites.
I did get 3 decent Milwaukee (mostly M18) deals on Woot.com, but you have to jump on those quickly.
There is a great website that does good price history + price comparison between HomeDepo, Lowe’s, and WalMart but I can’t find the link. If anyone has it, please share.
Sadly one of the best ways to get cheap Milwaukee M18 tools is the “hackable” sales from Home Depot: when 2 SKUs bought together makes them both cheaper, but if you buy them online and have the 2 SKUs sent to different HomeDepo stores, you can cancel one of the SKUs later and the non-cancelled one is deeply discounted. It’s probably a violation of ToS, but customer service reps allow it and support it, so maybe it’s not actually a violation… ? It feels like corporate may eventually ban users who abuse that and cost more money than they are worth.
Milwaukee doesn’t sell via Amazon or eBay and there are notoriously good Chinese clones on those sites.
I did get 3 decent Milwaukee (mostly M18) deals on Woot.com, but you have to jump on those quickly.
There is a great website that does good price history + price comparison between HomeDepo, Lowe’s, and WalMart but I can’t find the link. If anyone has it, please share.
> It’s probably a violation of ToS, but customer service reps allow it and support it, so maybe it’s not actually a violation… ? It feels like corporate may eventually ban users who abuse that and cost more money than they are worth.
I've done this at least a few dozen times over the past 4-5 years now. I have way more tools than is reasonable for my use-case. No problem so far.
From what I can tell HD doesn't seem to care much - the margin on these things has to be insane, so they are likely still making money on the transaction. Given how the discount is pro-rated across both SKUs you apply the deal to they likely did that on purpose. Who knows what rebates they are getting on the backend from Milwaukee on such promos, but I'd be surprised if there were none.
I imagine if you did this a dozen times in a given month they might ban you for outright suspected return fraud - but for most folks I don't think it's a major concern.
I've done this at least a few dozen times over the past 4-5 years now. I have way more tools than is reasonable for my use-case. No problem so far.
From what I can tell HD doesn't seem to care much - the margin on these things has to be insane, so they are likely still making money on the transaction. Given how the discount is pro-rated across both SKUs you apply the deal to they likely did that on purpose. Who knows what rebates they are getting on the backend from Milwaukee on such promos, but I'd be surprised if there were none.
I imagine if you did this a dozen times in a given month they might ban you for outright suspected return fraud - but for most folks I don't think it's a major concern.
https://toolguyd.com is good for tool sale notifications.
Acme Tools, sometimes Grainger will have a sale too
Home Depot website
Always love to see an in-depth reverse engineering write-up. This one's particularly interesting since I'm currently designing a battery pack for my own project.
Interesting to see a microcontroller (and quite a classic one...) as well as an ASIC for battery management. I imagine it's for communication purposes. The battery management chips I've been looking at have built in I2C interfaces to let me avoid firmware.
Interesting to see a microcontroller (and quite a classic one...) as well as an ASIC for battery management. I imagine it's for communication purposes. The battery management chips I've been looking at have built in I2C interfaces to let me avoid firmware.
I've been down this road before. The ASIC in the Milwaukee pack is known as an "analog front end". Since you can't wire cells directly up to the pins of your MCU, you have a chip to handle that stuff for you. It will let you read the voltage of each cell in the stack (some are literally analog, and just provide a nicely in-range voltage output for your MCU's ADC to read; others have internal ADCs). It might do current sensing. It might handle a couple alarms to turn off a mosfet when things go wrong. It will have an I2C interface, but the supported commands are "tell me voltage of cell #2" or "put shunt resistor on cell #1 for balancing". It's still the MCU that calls most of the shots here, but the more advanced ASICs can do more things autonomously.
There was a GitHub project a few years ago to try and RE the Milwaukee M18 system. I think it was based around this teardown: https://www.allaboutcircuits.com/news/teardown-tuesday-batte...
The MSP430 can be put into an extremely low power sleep mode (microAmps I believe, though you have to turn off all it's peripherals also) which means the MCU will not draw down the battery over time, leaving it fully charged and ready to be used even after long storage.
I have a substantial investment in both Dewalt and Milwaukee tools that I use regularly in my farming operation. I definitely prefer the Milwaukee tools to the Dewalt. I recently bought a 6" Milwaukee chain saw for light duty cutting. I get a lot of cuts before I have to change batteries. Also the torque in the Milwaukee 3/4" impact gun is truly amazing and the battery lasts through a lot of bolt removals.
I’ve found they excel in different areas. For wood working, dewalt is the clear winner. They have some of the best most cost effective major woodworking tool like planers and table saws. Milwaukee has an edge on impact drivers and little else. If you mostly work with wood, Dewalt is better. If you need impacts for auto work, Milwaukee edges out dewalt. It’s rarely worth investing in both platforms because the batteries are the most expensive component.
I use Dewalt for my woodworking stuff and Milwaukee M12 for this very reason. M12 for automotive for their high speed ratchet, 3/8” stubby impact, right angle die grinder, etc. Milwaukee seems to have an edge there although Dewalt isn’t far behind.
AVE had tear downs years ago and I think there were a few places where dewalt edged out Milwaukee. There was also some black magic going on with dewalt impacts and a rebound effect. See Torque test channel[1].
For automotive Milwaukee is the clear winner.
[1]https://youtu.be/tPP6exJyILA?si=G1aKZL9yjYwkJ2aH
For automotive Milwaukee is the clear winner.
[1]https://youtu.be/tPP6exJyILA?si=G1aKZL9yjYwkJ2aH
Milwaukee makes the best versions of lots of tools, mostly related to the electrical trade. The M12 portaband (one handed!) and M12 SDS plus hammer drills are amazing tools, and so are the M18 versions. Milwaukee has great lighting options too. My electricians can choose between Milwaukee and Makita, they all choose Milwaukee.
> Milwaukee has an edge on impact drivers and little else.
DeWalt's lighting options are terrible, compared to Milwaukee. Low run time and bad ergonomics.
In contrast, Milwaukee lights run much longer and have some neat solutions for disaster scenarios (lamp + USB charger).
DeWalt's lighting options are terrible, compared to Milwaukee. Low run time and bad ergonomics.
In contrast, Milwaukee lights run much longer and have some neat solutions for disaster scenarios (lamp + USB charger).
One Christmas, I was given a shiny new 14.4V Craftsman NiCad drill with two batteries. These were not cheap and I was young and broke and very grateful for the thoughtful gift. It worked great and I enjoyed it immensely. For about a year.
After that, neither pack would hold a charge long enough to be useful. Which I thought was pretty disgusting. Come to find out, this was basically the normal standard to which Craftsman had finally sunk. Rather than do the rational thing and throw it out, I held onto it with with a grudge and a goal of actually making it useful again one day.
A few years back, I found a decent deal on brand-new 18650 high-current LiFePo4 batteries from a reputable supplier ($2.50 each, sadly NLA) and bought up a bunch to remake the packs for this drill and a couple others I had laying around for similar reasons. I added an inexpensive but well-made BMS (which I tested thoroughly before implementing) and the voltage was upped to 16V nominal for a little extra kick. Don't ask how I spot-welded the tabs to the batteries.
4.5 years later and these drills are still going strong, I use them at least once a week on both small and large projects. They are not speed demons or torque monsters, but they drill all the holes I ask them to. Would I have been better off economically throwing these ones in the garbage and just buying the cheapest thing from Harbor Freight? Maybe.
But spite, it turns out, is its own reward and I would do it all over again a heartbeat.
After that, neither pack would hold a charge long enough to be useful. Which I thought was pretty disgusting. Come to find out, this was basically the normal standard to which Craftsman had finally sunk. Rather than do the rational thing and throw it out, I held onto it with with a grudge and a goal of actually making it useful again one day.
A few years back, I found a decent deal on brand-new 18650 high-current LiFePo4 batteries from a reputable supplier ($2.50 each, sadly NLA) and bought up a bunch to remake the packs for this drill and a couple others I had laying around for similar reasons. I added an inexpensive but well-made BMS (which I tested thoroughly before implementing) and the voltage was upped to 16V nominal for a little extra kick. Don't ask how I spot-welded the tabs to the batteries.
4.5 years later and these drills are still going strong, I use them at least once a week on both small and large projects. They are not speed demons or torque monsters, but they drill all the holes I ask them to. Would I have been better off economically throwing these ones in the garbage and just buying the cheapest thing from Harbor Freight? Maybe.
But spite, it turns out, is its own reward and I would do it all over again a heartbeat.
The Ryobi lithium batteries I got with my first cordless drill bundle at Home Depot in 2006 still work and still hold a useful amount of charge today. And the charger I got back then will charge the newest batteries - not as fast - but they charge.
Pretty amazing compared to what all batteries were like growing up in the 90s.
Pretty amazing compared to what all batteries were like growing up in the 90s.
Yeah, I have had a similar experience with a cheap craftsman drill that has lithium batteries. I don't use it a lot and it pretty much has a charge when I need it.
It might not have been Craftsman's fault; NiCad batteries are vulnerable to the memory effect, which means if they were not fully discharged when you recharge them, the maximum capacity shrinks.
The "memory effect" of NiCad batteries is an urban myth that got supercharged with a dose of confirmation bias. Nobody has replicated the memory effect in consumer batteries. When people think they are observing the memory effect, most of the time they are seeing the very high self-discharge rate of 10% (or very often more) per month of storage combined with regular human forgetfulness. They charge up the battery, let it sit for a few months, go to use it, notice it went dead faster than they expected, charge it up again, use it right away, and see that it's back up to normal capacity.
In my case, Craftsman just used REALLY bad cells, Plus there was no BMS, AND they wired them all in series so that if one or a few develop high internal resistance, basically the whole pack was shot. Very bad design + very cheap cells = designed obsolescence.
In my case, Craftsman just used REALLY bad cells, Plus there was no BMS, AND they wired them all in series so that if one or a few develop high internal resistance, basically the whole pack was shot. Very bad design + very cheap cells = designed obsolescence.
I thought the memory effect was basically a myth? https://en.wikipedia.org/wiki/Memory_effect
The EU is forcing toolmakers to use standard batteries. Hopefully we can get them in the US too.
Do you have a source for this? Because all I know is that this was an April fools joke from last year. I'm curious of the EU is now actually doing this.
Edit: Bamboozled by the search gods
That appears to be the abovementioned April Fools video.
Too bad this wasn't real, especially since at the end of the day, all these things are just using 18560 cells.
I tried to standardize on one system (Hikoki 18/36V). This was great as they use the same battery across consumer and pro products. But I moved from Japan to Europe and they are far less available, and more expensive. Now I buy Parkside stuff (Lidl brand) and they are probably a tier lower but better value and also use the same battery across consumer and pro products.
Anyway I felt lucky that I could buy both low and high(er) end cordless tools in two countries/brands and also find adapters to use both batteries in both sets of tools. Both systems don't have any sort of data handshake between tool and battery. Going forward, this will probably increasingly be the case so I would love for a standard to be enforced.
I tried to standardize on one system (Hikoki 18/36V). This was great as they use the same battery across consumer and pro products. But I moved from Japan to Europe and they are far less available, and more expensive. Now I buy Parkside stuff (Lidl brand) and they are probably a tier lower but better value and also use the same battery across consumer and pro products.
Anyway I felt lucky that I could buy both low and high(er) end cordless tools in two countries/brands and also find adapters to use both batteries in both sets of tools. Both systems don't have any sort of data handshake between tool and battery. Going forward, this will probably increasingly be the case so I would love for a standard to be enforced.
This would be painful in the short term because all my current tools and batteries would likely become obsolete, but it would be cool to see manufacturers more vigorously competing on battery specs like power and energy density.
There's also the risk that tool prices could go up as I suspect some tools are currently sold as a loss-leader to get you into "the system".
There's also the risk that tool prices could go up as I suspect some tools are currently sold as a loss-leader to get you into "the system".
> This would be painful in the short term because all my current tools and batteries would likely become obsolete
I have seen 3rd party battery accessories so anyone looking to make money might wind up making adapters to retrofit tools. Good for the environment too.
I have seen 3rd party battery accessories so anyone looking to make money might wind up making adapters to retrofit tools. Good for the environment too.
https://powertoolsadapters.com/ specializes in exactly this.
For some reason they insist in shoving some USB PSU in many of those adapters.
That will drain the battery by itself over time. So you then must make sure to remove the battery from the adapter as per instructions.
That is just so dumb, it's beyond my understanding.
That will drain the battery by itself over time. So you then must make sure to remove the battery from the adapter as per instructions.
That is just so dumb, it's beyond my understanding.
There's no reason a USB PSU couldn't have such a low quiescent current that you wouldn't notice it when there's no usb plug. No idea if they've done that there though.
Cheap design. You can do a shutdown and then have a controller go into deep sleep with picowatts of standby power consumption. A load connected wakes it up.
Unrelated, but Makita 18v has been an "unofficial" standard for cheap Chinese tool.
What do you mean by that? Makita tools are not known for being cheap.
There are a ton of tools on AliExpress that will fit Makita 18v batteries.
Some listings go so far as to be worded like “electric drill for Makita battery”.
Some listings go so far as to be worded like “electric drill for Makita battery”.
We've had universal adapters for ages. You can run a DeWalt battery on a Milwaukee, Makita on DeWalt, etc. I even have an adapter to run my Milwaukee M18 batteries on my Dyson vacuum.
You can run a wire to the pos/neg leads on the battery and use it standalone. I use it to power temporary reverse off-road lights on my truck. I see no reason to do this sort of thing. More oppressive regulation from the EU that no one actually wants. Fortunately Milwaukee is a US company as well as a dominant player in the market and will likely not participate in this whatsoever.
Milwaukee was a US company but has been a brand of Techtronic Industries, which is based in Hong Kong, for about 20 years now.
You have to be careful with the adapters because some brands have the circuitry that stops you running the battery too low in the tool and some in the battery. If you end up with a combo where that circuitry doesn’t exist you can over-deplete the battery.
Also: I want that regulation :)
Also: I want that regulation :)
Agree. The toolmakers don't impose some sort of coding (that I know of) so you can just use a 3rd party replacement battery too. I don't see a need to regulate this either.
I'm not sure I follow. Aren't all lithium charging circuits basically the same nowadays, namely an SMC paired with a voltage pump or switching power circuit?
This isn't the charging circuit - that goes in the charger. This circuit is responsible monitoring the state-of-charge (for that little LED bar graph on the front), disconnecting the cells if something goes wrong, and negotiating available current with the tool. It should also be responsible for cell balancing, but it looks like Milwaukee forgot to implement that feature (oops).
The videos at the bottom of the article have most of the details, since those dive into the communications protocols as opposed to the raw schematics.
The videos at the bottom of the article have most of the details, since those dive into the communications protocols as opposed to the raw schematics.
Their M12 batteries don't have balancing (or a BMS inside), so they go out of balance and 'bad' very quickly. I've just added a balance plug to the outside of mine that I plug into my hobby Li-ion charger.
I believe you on the technical details, but as an anecdote, I have M12 batteries that are 10 years old and still working fine. At least, good enough that I have noticed no issues with them and I don't even know off the top of my head which of my batteries are newer and which are older. I also have a bunch of M18 tools and batteries, and I've noticed no particular difference in how they age compared to the M12 ones. But I'm just a DIY homeowner, so my usage is relatively light.
Yeah I figure most of them work fine, otherwise I'd find more similar stories.
We have about 10 of the M12 batteries, about half are the 3 cell ones and half the 6 cell larger capacity ones. And every single one has gone completely out of balance within 2 years of use.
I plug them into a balancer and they last another solid 6 months or so.
We have about 10 of the M12 batteries, about half are the 3 cell ones and half the 6 cell larger capacity ones. And every single one has gone completely out of balance within 2 years of use.
I plug them into a balancer and they last another solid 6 months or so.
Fun fact, DeWalt 18/20V batteries also don't have balancing. The batteries have pins going to each cell for it but no chargers actually use them.
It's such a strange thing to do unless they wanted to intentionally make them have short lifespans.
The M12s have the pins too for voltage sensing in the charger (and tool maybe?), but they have 1 mega ohm resistors in line so cannot be used for balancing.
The M12s have the pins too for voltage sensing in the charger (and tool maybe?), but they have 1 mega ohm resistors in line so cannot be used for balancing.
DeWalt also makes a series of batteries that will either provide ~20v (5s3p) or ~60v (15s1p) depending on the tool you plug it into. I've taken one of these apart before and how they implement this is just a mechanical switch between the cell groups, which only gets depressed when inserted into 60v tools. Not sure if thats why they put all the circuitry on the tool side, but I can't think of another good way to implement the same. (You'd need a pretty beefy boost/buck controller for the amps these tools pull )
There are always two charging circuits for Li batteries, one in the battery and the other in the charger. They pair together to negotiate the voltage and current. There's a dedicated protocol to do this.
This is absolutely not "always" true. There are tons of 18650 cells that have no electronics whatsoever, and there are tons of dedicated charging ICs that connect directly to cells/batteries.
Youtube channel Torque Test Channel did a video on various new "tabless" batteries from various tool companies and most do provide more power per amp compared to the older models.
https://www.youtube.com/watch?v=QJuevwLJyMQ
https://www.youtube.com/watch?v=QJuevwLJyMQ
https://www.youtube.com/watch?v=q7spzrIbdKY
This guy has a few videos on his channel dedicated to the batteries.
This guy has a few videos on his channel dedicated to the batteries.
I have a big 21 volt power supply hooked up to the empty shell of one of these batteries, with a resistor divider supplying 3.3v to trigger the tools to accept power. It works.
Don't forget that you can buy fairly inexpensive adapters for the batteries. So, you can run your Dewalt on your Milwaukee batteries and not feel vendor locked.
As a heavy user of Milwaukee gear this is a very pertinent and interesting analysis.
One of my Makita 18V 1.5Ah failed a few days ago, I m tempted to by knockoff instead of the brand name.
Am I in danger?
Am I in danger?
Maybe. There's also a good chance you'll get a battery whose actual capacity is not less than what it says on the label. This Project Farm video looks into that question. https://youtu.be/Xf0qqsRMKpM
My friends and I have very mixed results with knockoff Makita batteries. Some work just as well as name brand, others have roughly half the rated capacity and perform much worse in the cold. I’m assuming your use case is light duty since you’re using a 1.5 Ah battery now, so getting a knockoff probably makes sense.
I’ve used knockoff M12 batteries for a while, no real issues. You can get them in larger capacities than the official Milwaukee ones which is my main use for them. I would imagine the Makitas are the same story.
There are a lot of fakes even if you try to buy OEM.
why cant i use an external DC power supply to replace the one in the chargers? no reason they cant be USB-c given proper supply but there seems to be some kind of special signaling.
The highest-current M12 battery (XC 4.0 Extended Capacity and XC 5.0 High Output) can deliver 600W peak; the highest-current standard M18 battery (High Output HD 12.0) can deliver 1620W; the highest-current M18 Forge battery (Forge HD 12.0) can deliver 3240W.[0]
There are vanishingly few AC-DC power supplies that can push 600W (that’s 50 amps at 12V), let alone 1620W (90 amps at 18V) or 3240W (180 amps!!) and definitely none with a USB-C plug on them. You’d realistically be limited to ~1500W on standard household receptacles, and you’d need some hefty cables on the output side of your power supply, especially if you want them to be jobsite-safe. For reference, 180 amps is in the same ballpark as EV fast charging stations; that’s a rough estimate on the size your cord would have to be plugged in to the bottom of the tool.
For the super light duty stuff like an M12 dremel, sure it’s doable. But for any tools that need high burst or sustained power, either a battery or just running the tool on 120V AC directly (or compressed air) is easier, cheaper, and probably safer.
[0] https://docs.google.com/spreadsheets/u/1/d/e/2PACX-1vRghl-44...
There are vanishingly few AC-DC power supplies that can push 600W (that’s 50 amps at 12V), let alone 1620W (90 amps at 18V) or 3240W (180 amps!!) and definitely none with a USB-C plug on them. You’d realistically be limited to ~1500W on standard household receptacles, and you’d need some hefty cables on the output side of your power supply, especially if you want them to be jobsite-safe. For reference, 180 amps is in the same ballpark as EV fast charging stations; that’s a rough estimate on the size your cord would have to be plugged in to the bottom of the tool.
For the super light duty stuff like an M12 dremel, sure it’s doable. But for any tools that need high burst or sustained power, either a battery or just running the tool on 120V AC directly (or compressed air) is easier, cheaper, and probably safer.
[0] https://docs.google.com/spreadsheets/u/1/d/e/2PACX-1vRghl-44...
if by "vanishingly few" you mean absolutely standard then you are correct. The small PSU I have in my home PC is 1000 watts. I have multiple kilowatt class AC-DC power supplies sitting around for other purposes. There is nothing special about that power level.
For perspective my DC welder is rated at 10000 watts of input. The efficiency is really poor however so I'd only see something like 4000 watts out in the best conditions.
For perspective my DC welder is rated at 10000 watts of input. The efficiency is really poor however so I'd only see something like 4000 watts out in the best conditions.
Because usbc doesn’t deliver 400w+ that those things use. Some of the multi chargers will happily suck down over a kilowatt sustained.
I appreciate the mild humor injected into various scenes.