7 ms·

Milwaukee M18 Battery Reverse Engineering

222 points by jakogut 1y ago

Liftyee 1y ago
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.
- alnwlsn 1y ago
  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.
- thephyber 1y ago
  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-battery-charger/ https://www.allaboutcircuits.com/news/teardown-tuesday-batte...
- rapjr9 1y ago
  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.
whalesalad 1y ago
As a heavy user of Milwaukee gear this is a very pertinent and interesting analysis.
gcormier 1y ago
https://www.youtube.com/watch?v=q7spzrIbdKY https://www.youtube.com/watch?v=q7spzrIbdKY This guy has a few videos on his channel dedicated to the batteries.
glitchc 1y ago
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?
- s_tec 1y ago
  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.
  - Saris 1y ago
    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.
    - nicolaslem 1y ago
      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.
      - Saris 1y ago
        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.
        notjulianjaynes 1y ago
throwaway48476 1y ago
The EU is forcing toolmakers to use standard batteries. Hopefully we can get them in the US too.
- aequitas 1y ago
  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.
  - toomuchtodo 1y ago
    Edit: Bamboozled by the search gods
    - kube-system 1y ago
      That appears to be the abovementioned April Fools video.
  - throwaway48476 1y ago
    https://eur-lex.europa.eu/eli/reg/2023/1542/oj/eng https://eur-lex.europa.eu/eli/reg/2023/1542/oj/eng
- AlexandrB 1y ago
  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".
  - MisterTea 1y ago
    > 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.
tomcam 1y ago
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.
- bombcar 1y ago
  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).
  - FlyingBears 1y ago
    Drug dealers give out feelers to get customers started.
  - wlesieutre 1y ago
    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.
    - terribleperson 1y ago
      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.
      - 1y ago
bityard 1y ago
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.
- mitthrowaway2 1y ago
  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.
  - kalleboo 1y ago
    I thought the memory effect was basically a myth? https://en.wikipedia.org/wiki/Memory_effect https://en.wikipedia.org/wiki/Memory_effect
  - bityard 1y ago
    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.
devwastaken 1y ago
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.
- TylerE 1y ago
  Because usbc doesn’t deliver 400w+ that those things use. Some of the multi chargers will happily suck down over a kilowatt sustained.
- jmb99 1y ago
  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-44o7Nw_GGOGKN8PdnxJtbzF7UR7nYDt3zEPrRL_azznKE1w4QvBJRLxdQnecwIgQ6tuuzQ4bT/pub https://docs.google.com/spreadsheets/u/1/d/e/2PACX-1vRghl-44...
  - sidewndr46 1y ago
    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.
stuckkeys 1y ago
I appreciate the mild humor injected into various scenes.
noefingway 1y ago
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.
- tstrimple 1y ago
  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.
  - ianschmitz 1y ago
    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.
    - wil421 1y ago
      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 https://youtu.be/tPP6exJyILA?si=G1aKZL9yjYwkJ2aH
  - ethbr1 1y ago
    > 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).
BonoboIO 1y ago
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?
- throwaway48476 1y ago
  There are a lot of fakes even if you try to buy OEM.
- jmb99 1y ago
  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.
- bruckie 1y ago
  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 https://youtu.be/Xf0qqsRMKpM
- mrWiz 1y ago
  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.
oakwhiz 1y ago
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.
latchkey 1y ago
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.
mrbigbob 1y ago
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

222 points by jakogut 1y ago

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.

alnwlsn 1y ago
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.
thephyber 1y ago
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-battery-charger/ https://www.allaboutcircuits.com/news/teardown-tuesday-batte...
rapjr9 1y ago
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.

whalesalad 1y ago

As a heavy user of Milwaukee gear this is a very pertinent and interesting analysis.

gcormier 1y ago

https://www.youtube.com/watch?v=q7spzrIbdKY https://www.youtube.com/watch?v=q7spzrIbdKY This guy has a few videos on his channel dedicated to the batteries.

glitchc 1y ago

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?

s_tec 1y ago
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.
- Saris 1y ago
  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.
  - nicolaslem 1y ago
    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.
    - Saris 1y ago
      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.
      - notjulianjaynes 1y ago

throwaway48476 1y ago

The EU is forcing toolmakers to use standard batteries. Hopefully we can get them in the US too.

aequitas 1y ago
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.
- toomuchtodo 1y ago
  Edit: Bamboozled by the search gods
  - kube-system 1y ago
    That appears to be the abovementioned April Fools video.
- throwaway48476 1y ago
  https://eur-lex.europa.eu/eli/reg/2023/1542/oj/eng https://eur-lex.europa.eu/eli/reg/2023/1542/oj/eng
AlexandrB 1y ago
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".
- MisterTea 1y ago
  > 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.

tomcam 1y ago

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.

bombcar 1y ago
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).
- FlyingBears 1y ago
  Drug dealers give out feelers to get customers started.
- wlesieutre 1y ago
  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.
  - terribleperson 1y ago
    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.
    - 1y ago

bityard 1y ago

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.

mitthrowaway2 1y ago
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.
- kalleboo 1y ago
  I thought the memory effect was basically a myth? https://en.wikipedia.org/wiki/Memory_effect https://en.wikipedia.org/wiki/Memory_effect
- bityard 1y ago
  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.

devwastaken 1y ago

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.

TylerE 1y ago
Because usbc doesn’t deliver 400w+ that those things use. Some of the multi chargers will happily suck down over a kilowatt sustained.
jmb99 1y ago
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-44o7Nw_GGOGKN8PdnxJtbzF7UR7nYDt3zEPrRL_azznKE1w4QvBJRLxdQnecwIgQ6tuuzQ4bT/pub https://docs.google.com/spreadsheets/u/1/d/e/2PACX-1vRghl-44...
- sidewndr46 1y ago
  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.

stuckkeys 1y ago

I appreciate the mild humor injected into various scenes.

noefingway 1y ago

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.

tstrimple 1y ago
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.
- ianschmitz 1y ago
  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.
  - wil421 1y ago
    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 https://youtu.be/tPP6exJyILA?si=G1aKZL9yjYwkJ2aH
- ethbr1 1y ago
  > 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).

BonoboIO 1y ago

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?

throwaway48476 1y ago
There are a lot of fakes even if you try to buy OEM.
jmb99 1y ago
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.
bruckie 1y ago
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 https://youtu.be/Xf0qqsRMKpM
mrWiz 1y ago
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.

oakwhiz 1y ago

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.

latchkey 1y ago

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.

mrbigbob 1y ago

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