Once again, people like you scratch a certain itch for me. Saving me countless hours researching and keyword searching for proprietary info. You’re the man
i don't know anything about power tools or electrical engineering but i still enjoy these videos and find them informative somehow. the videos are very well done, the data and research are provided in a really professional and well-laid out way, you explain what the data you gathered are and why they lead you to the conclusions that you draw. and i like the humor, it's like reading an actual paper but better
Your videos are awesome. I've done some similar, but more limited testing of M18 packs, though I never organized my thoughts like this. I've had pretty good luck with the various M18s, including the infamous 9, which has only recently started getting flaky (probably ~100-150 charge cycles.) I've had to balance it and my 12 (which is pretty new), but I chalk that up to Milwaukee's crappy BMS choices. I really wish Milwaukee would've put more of the BMS logic into the charger, where it could do smarter balancing, especially if the tool handles the cutoff anyway. The M12s are like that: the pins hit each cell bank and an extra one for a thermistor. Of course, it's not like the M12s are cheap, so clearly they aren't going to pass the savings of a simpler pack along.
Thanks, mate! M18 balance seems to be a problem of the chip they use only having a max balance current of 50mA, which was prob fine for 2ah-5ah packs, but not enough for 6-12ah. I think their biggest problem is that the charger doesn't stop and balance, or at least stay on slow charge, if it detects severe imbalance. There's definitely advantages to the 1 terminal per cell design of M12 and Dewalt 18V. Downside is increased chance of shorting and inability to brick a pack if it detects a fault. They also do whole pack low voltage cutoff, which isn't as good as per cell, but you could easily design the tool to have access to all the pins and then it's easy. Interestingly newer M12 packs seem to have electronics in them, so maybe they've built per cell LVC into them by having it short the thermistor to get the tool to shutdown. That's just another item on my ever growing todo list!
@@toolscientist Re: the one cell per terminal design of M12. There is something else inside the M12 batteries as well. I'm pretty sure it's just passive components, but last week I tried using a balance charger to charge an M12 battery and it flat out refused. The cell voltages started looking completely weird. Sticking a multimeter on the individual cell terminals shows the expected per cell voltages but once you start pushing power in, something else happens. The DeWalt 12v packs, of course, can be trivially balance charged using their terminals.
@@procrastinator1842 Wow. 1000 ohms is insanely high. That seems like it would severely limit the amount of balancing you could do to nearly zero. Any thoughts on why they do that? A 100 ohm resistor would more than suffice for current limiting. It is consistent with M18, though - not having much balance capability. :)
@gf2e my thoughts are it's just for monitoring, when m12 batteries start to fall out of balance, the charger does nothing to remedy it. My second thought is that the m12 'balance' pins are quite exposed so an accidental short circuit is quite possible, the 1k resistor between each balance point would equal 2k if shorted, making short circuit current a whopping 2mA.
Excited to watch this! Personally, I have noticed that low drain devices seem to drain tools lower than high drain devices due to detection being on operating voltage under load. Different tools also seem to cut off at varying voltages, which is interesting…
I have a high demand 9.0 that refuses to charge past 3 dots. I manually charge it full after every drain. I typically just balance the cells manually, not paying much attention to voltage so long as it's within a reasonable range. Always finding dramatic differences between banks. Had been wondering if there's any balancing going on, clearly not. Your videos are super fascinating, thank you for such an in depth explanation.
I'm pretty sure there is balancing, it's just fairly weak balancing. The 9ah, 8ah, and 12ah are using high capacity cells that are more prone to losing capacity. So these packs are more likely to get too out of balance for the balancing circuitry to bring them back into line.
I think most of my packs were slightly unbalanced at the start of their tests. I can go through my footage and post the start and end voltages if you're interested in which ones were due to imbalance and which are due to failing cells. Although any pack with a weak cell will most likely have imbalance anyway.
It is significant as one cell bank gets lower and oob it starts getting increasingly hammered by undervoltage. The cells would be fine if just balanced up but end up becoming weaker eventually due to this phenomenon and then throw error codes to the charger, the whole pack becoming unchargeable at that point. Probably a main type of failure. Tool batteries really need to be maintained and fully balanced up a couple of times a year. But very few people care to or know how to
I will have to test some of mine again one day. Mine were brand new back when testing. I have seen mine cut off at or around 3V in the past. That is of course allowing bounce back to equalize at 3V after 30 seconds or so. It definitely goes below 3V due to exactly what you mentioned the high current pulse shutdown issues. As you know if a pack shutdown after truly reaching 3V no matter what you would never be able to run many high current tools at all unless an almost full charge level. Not sure if it's a time limit or not, but very interesting that it still went low on your low current discharge test. One thing to check though is if the cells are old enough to drop off quickly is it dropping fast in the time limit of the cut off? Like the battery has lost capacity and drops off quicker at the lower voltage levels than usual. I know they already drop fast below 3V, but as they age it gets much worse. Excellent video, thanks for sharing and letting me know you had tested yours on video. I admit I thought yours were all fake or knockoff until you mentioned the difference... Those big numbers look fake dude...😂 Just not what I am used to.
They mostly rebounded back to 3V. I think I recorded some of them to check, but haven't looked too closely. That's a fuzzier number that depends on battery health, load, and capacity, whereas the 2V/cell and 2.5V/cell are pretty hard numbers that reveal a bit about Milwaukee's design philosophy (max power at all costs!) It will be interesting to test something like the handheld light, which claims 29hr runtime with a 5ah, so around 0.2A. If that goes down to 2V, without any timeout like you suggest, then the cells could be spending 5-30min below 2.5V, which I imagine would not be good for cell life. I'm not against them going down to 2V under high load, but only if they factor current into it, and it appears that they don't.
excellent analysis! I killed one of mine 5ah battery packs using an battery adapter for a makita tool. I meassured 2,5v in 2 rows of cells and -0,5v!!! in 3 rows of cells.
Thanks! This was actually just a detour on my way to making my mega battery review. I saw this unexpectedly low cutoff and felt it deserved its own video
@@Kevin.L_ yeah, I just keep getting side-tracked! I'm trying to characterise all the M18 batteries for internal resistance, thermal overload, max current, et cetera. Next vid (out in 5 hours) is a perfect example of getting side-tracked. I (mostly) reverse-engineered the M18 communication protocol to see if it gave me useful information like temperature, state of charge, and current. Took me over a month, but unfortunately the communication is fairly basic and doesn't give me anything I can use.
Oh man, can't believe I have more subs than you. You deserve millions of subs with this quality content and such knowledge. Instant subscribtion from myself. Now it all makes sense why some of my brand new batteries were killed in no time. Do you think if you have to explain to someone who is not so well educated on Milwaukee Battery and power tool tech that if you want to preserve your battery you need to recharge before it goes to 1 of 4 bars or even earlier? 2 bars left? Thanks in advance
2 bars would be ideal, but that can be painful. I've honestly never given it much thought, but I haven't had too many batteries die on me...yet. I also didn't know until now that the 18650 M18 batteries got discharged so low. On the other hand, some of my batteries are 2013 vintage and still seem to go fine. I'll be doing some capacity tests of all my batteries soon, so I'll see what that shows. The big thing would be not using the batteries until they're flat on low power tools. If you can hear the tool sounding slow, then prob time to change batteries.
@@toolscientist That makes so much more sense now. I was using an M12 usb power bank charger with M12 6.0 batteries. The slow drain must have ruined the batteries.
Achtung! Smetterling! Krankenwagen! A blast from the past there 😂. This data is my guilty pleasure. Ive been considering a similar rig for the m12 batteries. All I've found so far is that m12 low voltage cut out is 3.2v/cell.
I'm giving away my age aren't I. Need to spend all day on tikitok to get the freshest memes...actually, that sounds like an awful existance! Yeah, I'm pretty sure I got 9.6V cutoff. I wrote down the levels for all the indicator lights too. Took it as high as 14V before I chickened out, definitely no over-voltage protection, but there's no need for it in a proprietary system.
I have a 9.0Ah on my desk that all my M18 chargers refuse to charge. I distinctly remember it dying on my M18 string trimmer with the edging attachment. I popped open the case and all the cells look equal to me at 3.2V.
Great info. Just what I was looking for. This data is hard to find. Based on this info I think it does make sense to have some kind of secondary bms when using milwaukee power tools batteries for a power source, solarbgenerator or power station project. Only how to be able to read the cell imbalances in each pack when they are connected in series or paralell?
I wish I could give you an answer for this. Reading the battery to tool communication is high on my todo list, but I'm still probably several months away. A youtuber called "Buy It Fix It" seems to know the most about it. You can find his info on reddit by searching for "reddit m18 fuel battery protocol". Otherwise, I would just stick to 16V low voltage cutoff for the pack and periodically open your packs and rebalance.
Really interesting video and channel. Fairly new subscriber here and I'm suprised you don't have a lot more! Keep up the good work! Any plans on testing the new Forge 6.0 battery? I'd be curious to know if milwaukee has improved the BMS on these batteries with their claim of 2.5X longer life if I recall correctly. I also saw that the new dual bay supercharger utilizes all 5 pins (or at least has 5 pins) when I unboxed my charger. I believe all other M18 chargers just use 4 pins and not the one that connects to the + battery terminal (as you've mentioned as well). Thanks for the video! Really appreciated.
I have a lot of videos that I want to make, just not enough time to do them all. Takes me about 6 weeks per vid - hopefully I'll get more efficient at it. Oh, I just re-read your comment - I think you were referring to thinking I should have more subs, not more videos. It'll come with time. Getting into the nitty gritty of how tools work is also a bit more niche than the usual tool review/test channels. Most people just want to see Red vs Yellow vs Teal, et cetera. Forge isn't available in AU yet. It's got quite different circuitry from the one teardown that I've seen, so I am interested in seeing what's going on in there. Lifetime will be a tough one, I'd need to buy a brand new 6ah HO and 6ah Forge and put them through a few hundred cycles. Fairly painful to do manually, and getting a power supply and electronic load with serial interface will be pricey. It's probably something that I'll have to do eventually, though. I don't have a supercharger as they're not very common, so hard to find 2nd hand. I have seen the extra pin in photos, though. In the battery, the centre charging pin has a mosfet on it that can stop the charging current. That mosfet probably can't handle the high current of the supercharger, so they feed it direct via the B+ pin and then probably finish with the constant voltage phase on the centre pin. I would like to get hold of one to see if there's any extra messages in the protocol. That would be the one where I'd expect the high-output batteries to behave differently.
@@toolscientistYou are correct, I was referring to you not having as many subscribers as I thought you would've but they'll come. I always enjoy more videos though. The time it takes is probably what makes them so great! I wouldn't bother testing out life cycles in the 6.0 HO vs the 6.0 Forge. At least not for my sake. That works take so much time. I was just saying that if they've improved their BMS, and keep the voltage from dropping so low and also keep the cells better balanced that maybe that would contribute heavily to a longer life. I've noticed on the workshop addict video that the forge doesn't drop in voltage near as much as the other M18 batteries under load which should also help with that. Having said that, if you really feel like doing a life cycle test, I would definitely watch that video. Just might not be worth it to you. It probably is the mosfet that can't take the current. The single bay super charger just uses 4 pins and outputs 13.5 amps vs the dual bay supercharger that uses 5 pins and outputs 18 amps if just one battery is on that charger (and probably has to be a forge battery).
I've done Makita 18V (ua-cam.com/video/r1tQwoaCdBA/v-deo.html). 5Ah & 6Ah were 2.5V/cell but 1.5Ah and 3Ah were 1.7V/cell. Currently doing Dewalt - hoping to have the testing wrapped up this week. Vid in 1-2 weeks time.
@@toolscientist I have friends with DeWalt and Ryobi. I have Milwaukee myself. If you come up with a low voltage disconnect for DIY builds, it might make for good content. 🤷🏻♂️
They definitely have temp cutoff. In video [005] I show how I can trigger the cutoff signal by putting a resistor across the thermistor to teick it onto thinking it has overheated.
@philipdamjanov9099 yes. The battery detects and signals for cutoff (either low voltage or overtemp), but the tool (or my circuit) is what actually cuts the power. I haven't tested them yet, but Ridgid/AEG and Ryobi have stand-alone cutoff in the battery. Video [006] has me testing Makita and it seems only 5 & 6Ah have stand-alone cutoff in the battery.
In what manner does it tell the tool to stop? Is it an on/off output from the additional terminals of the battery? Or is it a digital communication or certain voltage that it sends to the tool?
They do not have low voltage protection. If using these batteries for kids power wheels etc - you can get a low voltage cutoff circuit ready to use for about 6.00$ on amazon. So I purchased a low voltage cutoff for my kids rise on cars…and never got around to installing it. Was never a problem for years and years on the 4&5ah batteries I have many of … not sure why. Not a problem at least until they used my 8.0 ho battery this weekend. And now that battery wont charge…. Kind of wondered if the ho battery with 21700 cells were more susceptible to low voltage when depleted.
One reason could be that the bigger and more powerful batteries can be drained lower by the car. The smaller packs get weaker faster, so your kids notice the loss of power and stop driving. The other reason is that 12ah and 8ah packs get unbalanced easily. Just like my 12ah where the pack was at 16V, but a few cells were empty. At 16V your car will still be going strong, so it will keep draining the weakest cells down to more damaging levels.
@@toolscientist Thank you for your reply! I am tempted to open and charge each cell individually one or few at a time to get it back in service. Do you think it will it balance the cells once on the charger?… or do I need to carefully do that myself?
If any of the cells are below 1V, then it's gone. If they're 1-2V, then the Samsung datasheets say you can slow charge to 3V at 0.4A. If it works, mark it with paint and keep an eye on it. Any sign of overheating in use or losing charge while resting means it's no good and better off recycled. You should try to balance the pack before putting it on the charger. M18 8ah and 12ah have balancing issues. I'm still trying to figure it out, but it seems that the balancing circuitry can't keep up, so the battery becomes unbalanced faster than it gets balanced.
Definitely open and check each cell bank. Bring up the low ones to the rest or top all of them off. I have brought back many packs that people discarded due to one cell bank being low
Love your video and yes these cells i noticed they are being drained un-evenly and also caused over charge during the charging process there is a company out there has figure out the timing of charging and resting a sequence to prolong the life of battery the bms is also very poorly designed, it doesn’t balance the cells during charging so far i noticed that high output 6.0 is the only can take beating on M12 side, XC 4.0 using Samsung 20R are very reliable yes Samsung 30Q was very very bad HD9.0, XC 6.0, M12 cp3 and XC6 had them till they switched to Muruta /Sony VTC 6 since late 2021
Couple of months away. I have a dewalt tool and battery. Just need to find a cheap charger. I'm moving to a different city in Jan, so that will wipe out a month or so of free time. Hopefully I'll have a Dewalt vid by March 2024 (don't quote me on that 😄)
Do you know how the battery signals the tool to stop? I know that Makita batteries do it by turning off the middle pin. So you can use that to switch a relay off. I wonder if there’s a similar thing that could be done for Milwaukee batteries?
J2 pin is held at ~3V for run, J2 gets pulled to 0V for stop. Turning J2 on needs a specific pulse on J1. I cover this in video [005] ua-cam.com/video/q7spzrIbdKY/v-deo.html
I have a few M18s where only one cell is lower voltage, usually around 3.5V while all the others are at 4V+. The resistance more or less matches with the rest of the cells and they don't look damaged either. Do you think simply charging the lower voltage cells and balancing the whole pack is a good idea? It seems to be working fine.
Afaik the EU market absolutely has Samsung 30T 21700 cells. A weird thing happens when the pack is 18v and 5.5ah, its under 100wh. It simplifies shipping and maybe does some other magic.
Almost certainly 30Ts. I was suggesting that the EU 5.5ah might be programmed differently so that it legitimately only has 100Wh, but they'd only do that if they had to. Seems that several brands manage to get away with labelling 6ah as 5.5ah.
I have a relatively newly replaced (by Milwaukee) m18 9.0AH battery where all three banks (purple cells, 40t I believe) show same voltage 4.45v, but the pack still blinks one light and charger shows green light when placed upon it. Any ideas? One time I did take the faulting pack and another, then smacked the bottoms together fairly hard and then the faulty pack showed 4 bars...placed it back in our wood cupboard for storage, then took it out to check it and it was back to flashing one bar. Ugh
Not if it's drained to zero. Check individual cell voltages. If they're all above 1V, then you can try recovery. Slow charge (100-400mA) and monitor temperature until all cells are over 2.5V, then try on the proper charger.
@zaneenaz4962 I've taken the 12ah up to 150A (50A/cell) and literally just (as in 5min ago) took the 2ah up to 50A (50A/cell) during testing for my next vid. 12ah is Samsung 40T 21700 cells. 2ah is Samsung 20R 18650 cells.
@zaneenaz4962 forgot to add, 12ah can go harder, but the tool (grinder) cuts out on it. 2ah is hitting low voltage cutoff at 50A and telling the tool to stop torturing it 😄
wow glad I went with bosch instead of Milwaukee. though that's mostly because the tool quality kinda sucks for the price. example last time i used one right out of the box the brushless motor screamed like a cat with it's balls stuck in a fence. chuck had run tons of run out and gritty with lots of metal dust coming out when sprayed with a little wd40. so i returned it and got another same issues.. so no quality control there . anyway i'd like to see some tests for bosch. they switched some of the exterior components of the batteries (different colors even) while keeping the same model numbers I think around 2021. ps to bosch tool,users the freak impact/socket driver lube the crap out of the inside retaining ball for the impact bits because it will friction weld to bit in the tool! learned that one the hard way
Definitely! Gotta collect 'em all and put them under the microscope. If they're all draining to 2V/cell, then this is unremarkable. But if Milwaukee is the only one doing it, then it kinda shows that they rate power over longevity.
why would they intentionally drain the cells that low? are they wanting to get you to buy new batteries? do they want to burn your house down? (for that reason if i was milwaukee i would use cheap shoddy underpowered cells like hoverboards used it has the same effect) or are they wanting the tool be compatible with nicd and nimh cells so older pre lithium cells would work or maybe so you can use an older say 12 or even 9 volt battery on a 20 volt tool.
I think it's just so they could push their tools harder without tripping low-voltage cutoff. The other possibility is that it's an oversight and they've forgotten to update their firmware. Back when M18 was released, high-powered Li-ion cells where very new, so maybe 2V was the norm back then. I tried looking for datasheets for the older Molicel cells, but they went bankrupt, so I think a lot of that info is lost.
Milwaukee works as hard as possible with the tools as seen in the video. At the point where another tool stops, Milwaukee continues to work. The user sees that Milwaukee appliances have higher performance, but this is a negative situation and is aimed entirely at deceiving the user. For this reason, Milwaukee appliances overheat and break down quickly. That's why I do not prefer Milwaukee.
Peak load currents times internal resistance could be big enough with certain loads that the under voltage protection circuit kicks in. That’s my hunch. Higher output batteries would be expected to have lower internal resistance, thus lower voltage drop with those same peak load currents.
Did you see the labelling, or are you just going off wrapper colour? Someone recently found that Milwaukee are using EVE 15M cells in their 3ah. EVE's 18650s have identical colour scheme to Samsung's, so impossible to tell from colour alone.
@@toolscientist yes Milwaukee switched up the recent 3Ah to Eve cells from the many failure of Samsung 15M and Samsung 30Q i got part of number which i am able to find matching VTC It is very rare, you can tell by looking at the top left corner 5INR22/70-3 the one uses Samsung 40T has 5INR22/71-3 same goes with 8Ah 70-2 is the one use VTC6A, they even use different BMS board
Does this mean that on the old batteries you should not use them until they're too low? Charge them before they die because they do not have the protection High Output series have?
All M18 batteries have low voltage detection and will tell the tool to cut out. The High Output batteries cutout at the recommended 2.5V/cell. The non-HO batteries cutout at 2V/cell ,which is below the recommended minimum. Whether or not this significantly reduces their lifetime is something that would take me a while to test. Overall, you are probably better off charging all batteries before they go completely flat.
![[005] How M18 batteries communicate with tools](http://i.ytimg.com/vi/q7spzrIbdKY/mqdefault.jpg)
![[005] How M18 batteries communicate with tools](/img/tr.png)
Once again, people like you scratch a certain itch for me. Saving me countless hours researching and keyword searching for proprietary info. You’re the man
Tell me more about this itch
it‘s one you want to take an angle grinder to..
i don't know anything about power tools or electrical engineering but i still enjoy these videos and find them informative somehow. the videos are very well done, the data and research are provided in a really professional and well-laid out way, you explain what the data you gathered are and why they lead you to the conclusions that you draw. and i like the humor, it's like reading an actual paper but better
Your videos are awesome. I've done some similar, but more limited testing of M18 packs, though I never organized my thoughts like this. I've had pretty good luck with the various M18s, including the infamous 9, which has only recently started getting flaky (probably ~100-150 charge cycles.) I've had to balance it and my 12 (which is pretty new), but I chalk that up to Milwaukee's crappy BMS choices. I really wish Milwaukee would've put more of the BMS logic into the charger, where it could do smarter balancing, especially if the tool handles the cutoff anyway. The M12s are like that: the pins hit each cell bank and an extra one for a thermistor. Of course, it's not like the M12s are cheap, so clearly they aren't going to pass the savings of a simpler pack along.
Thanks, mate!
M18 balance seems to be a problem of the chip they use only having a max balance current of 50mA, which was prob fine for 2ah-5ah packs, but not enough for 6-12ah. I think their biggest problem is that the charger doesn't stop and balance, or at least stay on slow charge, if it detects severe imbalance.
There's definitely advantages to the 1 terminal per cell design of M12 and Dewalt 18V. Downside is increased chance of shorting and inability to brick a pack if it detects a fault. They also do whole pack low voltage cutoff, which isn't as good as per cell, but you could easily design the tool to have access to all the pins and then it's easy. Interestingly newer M12 packs seem to have electronics in them, so maybe they've built per cell LVC into them by having it short the thermistor to get the tool to shutdown. That's just another item on my ever growing todo list!
@@toolscientist Re: the one cell per terminal design of M12. There is something else inside the M12 batteries as well. I'm pretty sure it's just passive components, but last week I tried using a balance charger to charge an M12 battery and it flat out refused. The cell voltages started looking completely weird. Sticking a multimeter on the individual cell terminals shows the expected per cell voltages but once you start pushing power in, something else happens.
The DeWalt 12v packs, of course, can be trivially balance charged using their terminals.
@gf2e there is a 1000 ohm resistor between each balance point and the pins. That would be the culprit.
@@procrastinator1842 Wow. 1000 ohms is insanely high. That seems like it would severely limit the amount of balancing you could do to nearly zero.
Any thoughts on why they do that? A 100 ohm resistor would more than suffice for current limiting.
It is consistent with M18, though - not having much balance capability. :)
@gf2e my thoughts are it's just for monitoring, when m12 batteries start to fall out of balance, the charger does nothing to remedy it. My second thought is that the m12 'balance' pins are quite exposed so an accidental short circuit is quite possible, the 1k resistor between each balance point would equal 2k if shorted, making short circuit current a whopping 2mA.
Excited to watch this!
Personally, I have noticed that low drain devices seem to drain tools lower than high drain devices due to detection being on operating voltage under load. Different tools also seem to cut off at varying voltages, which is interesting…
I have a high demand 9.0 that refuses to charge past 3 dots. I manually charge it full after every drain. I typically just balance the cells manually, not paying much attention to voltage so long as it's within a reasonable range. Always finding dramatic differences between banks. Had been wondering if there's any balancing going on, clearly not. Your videos are super fascinating, thank you for such an in depth explanation.
I'm pretty sure there is balancing, it's just fairly weak balancing. The 9ah, 8ah, and 12ah are using high capacity cells that are more prone to losing capacity. So these packs are more likely to get too out of balance for the balancing circuitry to bring them back into line.
Nice video, very good point about using adapters.
Interesting tests and analysis. The fact that its usually one bank dipping below the others is noteworthy. Good job on checking individual banks.
I think most of my packs were slightly unbalanced at the start of their tests. I can go through my footage and post the start and end voltages if you're interested in which ones were due to imbalance and which are due to failing cells. Although any pack with a weak cell will most likely have imbalance anyway.
It is significant as one cell bank gets lower and oob it starts getting increasingly hammered by undervoltage. The cells would be fine if just balanced up but end up becoming weaker eventually due to this phenomenon and then throw error codes to the charger, the whole pack becoming unchargeable at that point. Probably a main type of failure.
Tool batteries really need to be maintained and fully balanced up a couple of times a year. But very few people care to or know how to
Randomly recommended your channel.
I don't mind the videos being a little longer.
I will have to test some of mine again one day. Mine were brand new back when testing. I have seen mine cut off at or around 3V in the past. That is of course allowing bounce back to equalize at 3V after 30 seconds or so. It definitely goes below 3V due to exactly what you mentioned the high current pulse shutdown issues. As you know if a pack shutdown after truly reaching 3V no matter what you would never be able to run many high current tools at all unless an almost full charge level. Not sure if it's a time limit or not, but very interesting that it still went low on your low current discharge test. One thing to check though is if the cells are old enough to drop off quickly is it dropping fast in the time limit of the cut off? Like the battery has lost capacity and drops off quicker at the lower voltage levels than usual. I know they already drop fast below 3V, but as they age it gets much worse. Excellent video, thanks for sharing and letting me know you had tested yours on video. I admit I thought yours were all fake or knockoff until you mentioned the difference...
Those big numbers look fake dude...😂
Just not what I am used to.
They mostly rebounded back to 3V. I think I recorded some of them to check, but haven't looked too closely. That's a fuzzier number that depends on battery health, load, and capacity, whereas the 2V/cell and 2.5V/cell are pretty hard numbers that reveal a bit about Milwaukee's design philosophy (max power at all costs!)
It will be interesting to test something like the handheld light, which claims 29hr runtime with a 5ah, so around 0.2A. If that goes down to 2V, without any timeout like you suggest, then the cells could be spending 5-30min below 2.5V, which I imagine would not be good for cell life.
I'm not against them going down to 2V under high load, but only if they factor current into it, and it appears that they don't.
@@toolscientist
Excellent point! I would like to see how the light would do as well!
Excellent content!! Thank you for taking the time to gather this data.
So interesting, and so unknown channel. Don't give up, you need to grow!
Aww, thanks mate!
Good videos . What is the resistance value that used with the power supply?
this is an excellent channel and i'm looking forward to many more videos like the ones you've got!
excellent analysis! I killed one of mine 5ah battery packs using an battery adapter for a makita tool. I meassured 2,5v in 2 rows of cells and -0,5v!!! in 3 rows of cells.
Yikes, that's pretty dead!
@4:28, of course it's not a fluke, it's a Milwaukee! Anyway, strangely fascinating video. Thanks!
Best tool battery video I've seen yet!
Thanks! This was actually just a detour on my way to making my mega battery review. I saw this unexpectedly low cutoff and felt it deserved its own video
@@toolscientistSo are you still working on the mega review?
@@Kevin.L_ yeah, I just keep getting side-tracked! I'm trying to characterise all the M18 batteries for internal resistance, thermal overload, max current, et cetera. Next vid (out in 5 hours) is a perfect example of getting side-tracked. I (mostly) reverse-engineered the M18 communication protocol to see if it gave me useful information like temperature, state of charge, and current. Took me over a month, but unfortunately the communication is fairly basic and doesn't give me anything I can use.
@@toolscientist I just found that video announcement. Cool.
Every detour is a learning experience. Thanks for sharing your findings.
Great video! It is so revealing. I just found your channel, and you, sir, have earned my sub! 🙌
Keep them coming 👀
Oh man, can't believe I have more subs than you. You deserve millions of subs with this quality content and such knowledge. Instant subscribtion from myself. Now it all makes sense why some of my brand new batteries were killed in no time. Do you think if you have to explain to someone who is not so well educated on Milwaukee Battery and power tool tech that if you want to preserve your battery you need to recharge before it goes to 1 of 4 bars or even earlier? 2 bars left?
Thanks in advance
2 bars would be ideal, but that can be painful. I've honestly never given it much thought, but I haven't had too many batteries die on me...yet. I also didn't know until now that the 18650 M18 batteries got discharged so low. On the other hand, some of my batteries are 2013 vintage and still seem to go fine. I'll be doing some capacity tests of all my batteries soon, so I'll see what that shows.
The big thing would be not using the batteries until they're flat on low power tools. If you can hear the tool sounding slow, then prob time to change batteries.
@@toolscientist That makes so much more sense now. I was using an M12 usb power bank charger with M12 6.0 batteries. The slow drain must have ruined the batteries.
Achtung! Smetterling! Krankenwagen! A blast from the past there 😂.
This data is my guilty pleasure. Ive been considering a similar rig for the m12 batteries. All I've found so far is that m12 low voltage cut out is 3.2v/cell.
I'm giving away my age aren't I. Need to spend all day on tikitok to get the freshest memes...actually, that sounds like an awful existance!
Yeah, I'm pretty sure I got 9.6V cutoff. I wrote down the levels for all the indicator lights too. Took it as high as 14V before I chickened out, definitely no over-voltage protection, but there's no need for it in a proprietary system.
@@toolscientist oh cool. Care to share the voltage steps? Do they correspond to 25% capacity steps? Cheers.
@procrastinator1842 1 bar
You're awesome. Subscribed.
I have a 9.0Ah on my desk that all my M18 chargers refuse to charge. I distinctly remember it dying on my M18 string trimmer with the edging attachment. I popped open the case and all the cells look equal to me at 3.2V.
Interesting. You might be able to tap into the comms with a logic analyser to see where it fails.
Great info. Just what I was looking for. This data is hard to find. Based on this info I think it does make sense to have some kind of secondary bms when using milwaukee power tools batteries for a power source, solarbgenerator or power station project. Only how to be able to read the cell imbalances in each pack when they are connected in series or paralell?
I wish I could give you an answer for this. Reading the battery to tool communication is high on my todo list, but I'm still probably several months away. A youtuber called "Buy It Fix It" seems to know the most about it. You can find his info on reddit by searching for "reddit m18 fuel battery protocol".
Otherwise, I would just stick to 16V low voltage cutoff for the pack and periodically open your packs and rebalance.
Really interesting video and channel. Fairly new subscriber here and I'm suprised you don't have a lot more! Keep up the good work!
Any plans on testing the new Forge 6.0 battery? I'd be curious to know if milwaukee has improved the BMS on these batteries with their claim of 2.5X longer life if I recall correctly. I also saw that the new dual bay supercharger utilizes all 5 pins (or at least has 5 pins) when I unboxed my charger. I believe all other M18 chargers just use 4 pins and not the one that connects to the + battery terminal (as you've mentioned as well). Thanks for the video! Really appreciated.
I have a lot of videos that I want to make, just not enough time to do them all. Takes me about 6 weeks per vid - hopefully I'll get more efficient at it. Oh, I just re-read your comment - I think you were referring to thinking I should have more subs, not more videos. It'll come with time. Getting into the nitty gritty of how tools work is also a bit more niche than the usual tool review/test channels. Most people just want to see Red vs Yellow vs Teal, et cetera.
Forge isn't available in AU yet. It's got quite different circuitry from the one teardown that I've seen, so I am interested in seeing what's going on in there. Lifetime will be a tough one, I'd need to buy a brand new 6ah HO and 6ah Forge and put them through a few hundred cycles. Fairly painful to do manually, and getting a power supply and electronic load with serial interface will be pricey. It's probably something that I'll have to do eventually, though.
I don't have a supercharger as they're not very common, so hard to find 2nd hand. I have seen the extra pin in photos, though. In the battery, the centre charging pin has a mosfet on it that can stop the charging current. That mosfet probably can't handle the high current of the supercharger, so they feed it direct via the B+ pin and then probably finish with the constant voltage phase on the centre pin. I would like to get hold of one to see if there's any extra messages in the protocol. That would be the one where I'd expect the high-output batteries to behave differently.
@@toolscientistYou are correct, I was referring to you not having as many subscribers as I thought you would've but they'll come. I always enjoy more videos though. The time it takes is probably what makes them so great!
I wouldn't bother testing out life cycles in the 6.0 HO vs the 6.0 Forge. At least not for my sake. That works take so much time. I was just saying that if they've improved their BMS, and keep the voltage from dropping so low and also keep the cells better balanced that maybe that would contribute heavily to a longer life. I've noticed on the workshop addict video that the forge doesn't drop in voltage near as much as the other M18 batteries under load which should also help with that. Having said that, if you really feel like doing a life cycle test, I would definitely watch that video. Just might not be worth it to you.
It probably is the mosfet that can't take the current. The single bay super charger just uses 4 pins and outputs 13.5 amps vs the dual bay supercharger that uses 5 pins and outputs 18 amps if just one battery is on that charger (and probably has to be a forge battery).
great tests, thanks for the video.
curious to know about high voltage cutoff and balancing cells (if any?)
Charging voltage seems to be 4.19V, but I haven't tested thoroughly yet. Balancing is definitely high on my todo list!
Is there an equivalant video for the other brands? I appreciate the info from this one regardless
I've done Makita 18V (ua-cam.com/video/r1tQwoaCdBA/v-deo.html). 5Ah & 6Ah were 2.5V/cell but 1.5Ah and 3Ah were 1.7V/cell. Currently doing Dewalt - hoping to have the testing wrapped up this week. Vid in 1-2 weeks time.
@@toolscientist I have friends with DeWalt and Ryobi. I have Milwaukee myself. If you come up with a low voltage disconnect for DIY builds, it might make for good content. 🤷🏻♂️
Hi, Thanks for a good video, do you know if the battery has temperature cut of
They definitely have temp cutoff. In video [005] I show how I can trigger the cutoff signal by putting a resistor across the thermistor to teick it onto thinking it has overheated.
I watch the video 5, and if i did not misunderstand, it is not the battery itself there shutoffs it's the little circuit you made correct?
@philipdamjanov9099 yes. The battery detects and signals for cutoff (either low voltage or overtemp), but the tool (or my circuit) is what actually cuts the power. I haven't tested them yet, but Ridgid/AEG and Ryobi have stand-alone cutoff in the battery. Video [006] has me testing Makita and it seems only 5 & 6Ah have stand-alone cutoff in the battery.
In what manner does it tell the tool to stop? Is it an on/off output from the additional terminals of the battery? Or is it a digital communication or certain voltage that it sends to the tool?
It's an on/off signal on the J2 pin (inner pin next to B-). J2 @ 3V = go, J2 @ 0V = stop. ua-cam.com/video/q7spzrIbdKY/v-deo.html
They do not have low voltage protection. If using these batteries for kids power wheels etc - you can get a low voltage cutoff circuit ready to use for about 6.00$ on amazon.
So I purchased a low voltage cutoff for my kids rise on cars…and never got around to installing it.
Was never a problem for years and years on the 4&5ah batteries I have many of … not sure why.
Not a problem at least until they used my 8.0 ho battery this weekend. And now that battery wont charge…. Kind of wondered if the ho battery with 21700 cells were more susceptible to low voltage when depleted.
One reason could be that the bigger and more powerful batteries can be drained lower by the car. The smaller packs get weaker faster, so your kids notice the loss of power and stop driving.
The other reason is that 12ah and 8ah packs get unbalanced easily. Just like my 12ah where the pack was at 16V, but a few cells were empty. At 16V your car will still be going strong, so it will keep draining the weakest cells down to more damaging levels.
@@toolscientist Thank you for your reply!
I am tempted to open and charge each cell individually one or few at a time to get it back in service.
Do you think it will it balance the cells once on the charger?… or do I need to carefully do that myself?
If any of the cells are below 1V, then it's gone. If they're 1-2V, then the Samsung datasheets say you can slow charge to 3V at 0.4A. If it works, mark it with paint and keep an eye on it. Any sign of overheating in use or losing charge while resting means it's no good and better off recycled.
You should try to balance the pack before putting it on the charger. M18 8ah and 12ah have balancing issues. I'm still trying to figure it out, but it seems that the balancing circuitry can't keep up, so the battery becomes unbalanced faster than it gets balanced.
Definitely open and check each cell bank. Bring up the low ones to the rest or top all of them off. I have brought back many packs that people discarded due to one cell bank being low
Love your video
and yes these cells i noticed they are being drained un-evenly and also caused over charge during the charging process
there is a company out there has figure out the timing of charging and resting a sequence to prolong the life of battery
the bms is also very poorly designed, it doesn’t balance the cells during charging
so far i noticed that high output 6.0 is the only can take beating
on M12 side, XC 4.0 using Samsung 20R are very reliable
yes Samsung 30Q was very very bad
HD9.0, XC 6.0, M12 cp3 and XC6 had them till they switched to Muruta /Sony VTC 6 since late 2021
Please do this for dewalt! This is amazing stuff and really interesting
Couple of months away. I have a dewalt tool and battery. Just need to find a cheap charger. I'm moving to a different city in Jan, so that will wipe out a month or so of free time. Hopefully I'll have a Dewalt vid by March 2024 (don't quote me on that 😄)
Do you know how the battery signals the tool to stop? I know that Makita batteries do it by turning off the middle pin. So you can use that to switch a relay off.
I wonder if there’s a similar thing that could be done for Milwaukee batteries?
J2 pin is held at ~3V for run, J2 gets pulled to 0V for stop. Turning J2 on needs a specific pulse on J1. I cover this in video [005] ua-cam.com/video/q7spzrIbdKY/v-deo.html
@@toolscientist Awesome info! Is the reason you can’t just continuously apply 12v to J1 because then J2 will never go low?
@karlkalina3022 No. If J1 is held high for more than 40ms, J2 will go low again. You need to give J1 a pulse longer than 20ms but shorter than 40ms.
I have a few M18s where only one cell is lower voltage, usually around 3.5V while all the others are at 4V+. The resistance more or less matches with the rest of the cells and they don't look damaged either.
Do you think simply charging the lower voltage cells and balancing the whole pack is a good idea?
It seems to be working fine.
I'd try manually balancing the cells first.
Wait they don’t have cell balancing?
Anyhow, it would be nice if the BMS estimated the non-sagging voltage based on integrated current measurements.
They have cell balancing, it just seems to have trouble keeping up, especially on higher capacity batteries.
Afaik the EU market absolutely has Samsung 30T 21700 cells. A weird thing happens when the pack is 18v and 5.5ah, its under 100wh. It simplifies shipping and maybe does some other magic.
Almost certainly 30Ts. I was suggesting that the EU 5.5ah might be programmed differently so that it legitimately only has 100Wh, but they'd only do that if they had to. Seems that several brands manage to get away with labelling 6ah as 5.5ah.
I have a relatively newly replaced (by Milwaukee) m18 9.0AH battery where all three banks (purple cells, 40t I believe) show same voltage 4.45v, but the pack still blinks one light and charger shows green light when placed upon it. Any ideas? One time I did take the faulting pack and another, then smacked the bottoms together fairly hard and then the faulty pack showed 4 bars...placed it back in our wood cupboard for storage, then took it out to check it and it was back to flashing one bar. Ugh
9ah or 12ah? Samsung 40T is in the 8ah and 12ah. The 9ah had Samsung 30Q or LG HG2. 4.45v is very high, max should be 4.2V.
The old digitech multimeter. A fellow Jaycar enthusiast I see. :D
Busted!
Is it possible to charge up a battery drained down to zero in the case of Dewalt with adapter on M18 tool?
Not if it's drained to zero. Check individual cell voltages. If they're all above 1V, then you can try recovery. Slow charge (100-400mA) and monitor temperature until all cells are over 2.5V, then try on the proper charger.
@ really appreciate it! Great work
What a tour de force video on these battery packs ....are they really in 2p configuration ?
You state 20-30A per tool and 15A per cell.
2ah and 3ah high output are 5s1p, 12ah is 5s3p. All the rest are 5s2p.
@@toolscientist So they can be pulling as much as 15A/cell ? Thanks
@zaneenaz4962 I've taken the 12ah up to 150A (50A/cell) and literally just (as in 5min ago) took the 2ah up to 50A (50A/cell) during testing for my next vid.
12ah is Samsung 40T 21700 cells. 2ah is Samsung 20R 18650 cells.
@zaneenaz4962 forgot to add, 12ah can go harder, but the tool (grinder) cuts out on it. 2ah is hitting low voltage cutoff at 50A and telling the tool to stop torturing it 😄
@@toolscientist Amazing Numbers !! Greatly appreciate your work !!!
wow glad I went with bosch instead of Milwaukee. though that's mostly because the tool quality kinda sucks for the price. example last time i used one right out of the box the brushless motor screamed like a cat with it's balls stuck in a fence. chuck had run tons of run out and gritty with lots of metal dust coming out when sprayed with a little wd40. so i returned it and got another same issues.. so no quality control there . anyway i'd like to see some tests for bosch. they switched some of the exterior components of the batteries (different colors even) while keeping the same model numbers I think around 2021. ps to bosch tool,users the freak impact/socket driver lube the crap out of the inside retaining ball for the impact bits because it will friction weld to bit in the tool! learned that one the hard way
would you consider doing these tests with dewalt batteries?
Definitely! Gotta collect 'em all and put them under the microscope. If they're all draining to 2V/cell, then this is unremarkable. But if Milwaukee is the only one doing it, then it kinda shows that they rate power over longevity.
why would they intentionally drain the cells that low?
are they wanting to get you to buy new batteries?
do they want to burn your house down? (for that reason if i was milwaukee i would use cheap shoddy underpowered cells like hoverboards used it has the same effect)
or are they wanting the tool be compatible with nicd and nimh cells so older pre lithium cells would work or maybe so you can use an older say 12 or even 9 volt battery on a 20 volt tool.
I think it's just so they could push their tools harder without tripping low-voltage cutoff. The other possibility is that it's an oversight and they've forgotten to update their firmware. Back when M18 was released, high-powered Li-ion cells where very new, so maybe 2V was the norm back then. I tried looking for datasheets for the older Molicel cells, but they went bankrupt, so I think a lot of that info is lost.
Milwaukee works as hard as possible with the tools as seen in the video. At the point where another tool stops, Milwaukee continues to work. The user sees that Milwaukee appliances have higher performance, but this is a negative situation and is aimed entirely at deceiving the user. For this reason, Milwaukee appliances overheat and break down quickly. That's why I do not prefer Milwaukee.
Peak load currents times internal resistance could be big enough with certain loads that the under voltage protection circuit kicks in. That’s my hunch. Higher output batteries would be expected to have lower internal resistance, thus lower voltage drop with those same peak load currents.
I discovered that some of Milwaukee M18 12Ah using Sony VTC6A in them
most are Samsung 40T
Did you see the labelling, or are you just going off wrapper colour? Someone recently found that Milwaukee are using EVE 15M cells in their 3ah. EVE's 18650s have identical colour scheme to Samsung's, so impossible to tell from colour alone.
@@toolscientist yes Milwaukee switched up the recent 3Ah to Eve cells from the many failure of Samsung 15M and Samsung 30Q
i got part of number which i am able to find matching VTC
It is very rare, you can tell by looking at the top left corner 5INR22/70-3
the one uses Samsung 40T has 5INR22/71-3
same goes with 8Ah 70-2 is the one use VTC6A, they even use different BMS board
Good vid
Does this mean that on the old batteries you should not use them until they're too low? Charge them before they die because they do not have the protection High Output series have?
All M18 batteries have low voltage detection and will tell the tool to cut out. The High Output batteries cutout at the recommended 2.5V/cell. The non-HO batteries cutout at 2V/cell ,which is below the recommended minimum. Whether or not this significantly reduces their lifetime is something that would take me a while to test. Overall, you are probably better off charging all batteries before they go completely flat.
👍
This is why i use makita