Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusing

[sam_sam_sam]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

Yes most of the time (80%) it is inter battery cell and about (20%) of time it could be on either end

[redwire]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

Is it still the pack's inner cells that are a problem? I am thinking of the heat, because they run hotter than the outside cells and not sure where the BMS gets temperature from.

[sam_sam_sam]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

I have done some 8 amp hour Milwaukee m18 battery packs that one of them had a very bad cell rail that was at “0” volts and the other battery cells were around 3.something so I had some use decent 21700 cell that the battery cells were so out of balance that there was no hope that they would function properly so I replaced it with some battery cells that were just above 3.1something volts and ran each battery cell rail down to around 2 volts or so and recharged them on the Milwaukee battery charger and the battery voltage is somewhat unbalanced but they are a lot closer than they were 3.9something to 4.something and the total battery voltage is suppose to be around 21.00 volts and I now have around 20.something so let see how long this last

These Milwaukee battery packs there are two of them are used at work every day for a blower to clean the floor where there is no air lines close by

In fact one battery pack was so unbalanced that the charger was giving an charging error and refusing to charge anymore so it was time to figure out why this battery pack was so unbalanced that it just simpler to just remove all of the battery cells and start over with newer battery cells

One battery pack had one unbalanced cell rail but it was not terrible but enough that the BMS board would not allow it to completely charge the other one was the one that was extremely unbalanced and was not used instead I had one that I mentioned earlier that had one battery cell rail that was at “0” volts just replace it with some other used battery cells that were very close to the test results from the other cells that were still decent

[sam_sam_sam]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

Once a cell deep discharges it's very bad/hard on them.

You would think that when heat hitting the pack of battery pack cells they should all fail but this is not the case because I just tested a tool battery pack that one of the outer battery cell pack has the issue the rest of the battery pack cell rails do not seem to have this issue yet so let what more time does to them

I have also seen this happening with single row tool battery pack cells I have not figured exactly what causes certain battery cells to begin to have the issue of self discharging after sitting not being used for over a month or two

This seems to be the biggest problem with the tool battery pack cells ( you use them extremely hard frequently and wait until you have 2 fuel gauge lights left or the last fuel gauge light is flashing and now you have no more battery power )

I going do some testing on these BMS protection boards for Milwaukee battery pack cells because this seems to happen more often with them than with the Ryobi battery packs and I have both brands for many years now

In the Ryobi battery pack cells more often than not the battery pack cells when they go bad the voltage becomes extremely low to point that you would be fearful of trying to revive them

So I am with you about being shite battery cells but they are supposedly a good battery brand unless there quality has gone down the toilet which is a shame if this is the case

Milwaukee and Ryobi basically use the same battery manufacturer but not the same series so this might have something to do with what happens to power tool battery pack cells going bad the difference between what happens to each tool manufacturers battery pack when they go bad

I have been looking at some active battery balancing boards ( the type that is not a charging board BMS ) not the capacitor type but the other type that actually puts a load on the battery pack cells to rebalance them I going to see if this useful for rebalancing power tool battery packs or not

[redwire]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

If it is the inner cells that fail, then their heat has to be part of the problem.
If you heat up the center cells during high drain, and then heat them with high charge rate, I can't see them being happy campers.

The BMS likely doesn't know the cell temperatures accurately enough? Or it's lower quality batteries or a shitty BMS it sounds like.
Once a cell deep discharges it's very bad/hard on them.

[sam_sam_sam]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

The battery stud welder has it own controller issues if I am lucky I can get a couple of years out of them that are the original ones luckily they are kinds of transformer controllers out there on eBay and AliExpress and Banggood fairly cheap controllers but they do not also last but a few years if you use it a lot

[CapLeaker]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

Hmm… yeah I can see the grinder chewing up some power specifically if you lay on it. Damn that radio should last forever on a 12 Ah battery with a 30min per day usage. A fiend of mine has the same 12AH battery using it for his weed eater and blower. It lasts a very long time. However up here it isn’t that hot like it is down there.
Now looking at your cells on the last pic, #2 and #3 definitely have a problem with internal resistance. So yes, these are screwed.
Many years ago I was active on a different forum that was about resurrecting / rejuvenating batteries. I’ve did so many times with lead acid and NIMH. I had no interest on NICD, and the LI-ION were still newish. The idea was to pulse the battery with spikes. So we build all kinds of chargers to get these old cells going again. Some successful some not. It depended on far the battery was gone and what chemistry it was. Since I didn’t have a bad LI-ION at the time I never tried to build or modify for these. After that we had a few health emergencies and I never got back to it and I am still playing catch-up many years later.
One guy used something like a mixture between “Bendini” and re-emf with promising results. I’ve made all kinds of different desulfators and chargers for lead acid batteries and I still use them. So far I had good luck with LI-ION and all I really try is to keep the temperature of the battery down if I can. Since then I never got back into it building a new charger.
With your fancy charger you can identify bad cells easy and Frankenstein something together, by replacing the bad cells somehow. Nice rig!

[sam_sam_sam]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

Impact gun / grinder with wire wheel / cutting disk / grinding disk - drill with large drill bit sometimes I do not have the vacuum from Milwaukee but from Ryobi but I use a 4 amp hour battery on that one I also have weeds eater from them the blower and most of the time I use the 4 amp hour battery packs

Now what I use the 12 and 9 amp hour battery packs for the boombox that I have from them and I use it every work day I listen to the radio during lunch which is 30 minutes long

It will last a about 2 weeks doing that sometimes if have to use a wire wheel for a long time I use the 9 or 12 amp hour battery packs for that

Here is an example of a battery cell that has issues when the battery became unbalanced this charging curve looks like shit I would not use this for a power tool anymore the discharge curve drops really fast at the beginning when the load is turned on it should not look like that this is other reasons why I would not use it for a power tool anymore it will cause it to trip the BMS protection board earlier than normal

The parameters are as follows

4.2 cutoff voltage
1 amp charging rate
Temperature cutoff is set to 40*C

It suppose to look more like the second picture but even this one does not look real great but it is still useable for lower amp hour battery cell usage what is wrong with the second curve is it is too steep when the charging cycle starts it should like a slight increase in voltage but not like you see it

The reason I am using this battery testing machine is because I want to make sure that these battery cells do not have a temperature issue because I am not babysitting these batteries while they are on charge

But now that I have cycle them a few times I will now use the other battery testing machine for a more accurate view of graphics curve chart to determine which of these battery cells I can reuse for a power tool battery pack
(If any of them are still good enough for this purpose or not ) where I work they have a couple of Milwaukee battery packs that are 6 amp hour that the battery charger can not charge correctly anymore and I am sure it is that they are very unbalanced as well

The second battery cell is the first graph curve the second picture shows the curve graph is the fourth battery cell

[CapLeaker]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

Then I am guessing these battery packs get toasted down there the same way like car batteries. All the heat kills them over time. I’ve just gotten the large batteries 8Ah and 12AH lately.
What kind of tool is it? Impact wrench, vacuum, weed eater or a blower?

[sam_sam_sam]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

I have left the battery on the battery charger for days and this does not make a difference as far as the battery cells being unbalanced remember that I have had them for over three or four years by now and I use them very hard ( meaning that the battery packs is very warm to the touch) when I use them most of the time do not very often charge them when I have finished using them if they have more than 2 LED lights that are on the fuel gauge also it does not help that I keep some of them in my car at least most of times covered with a sweater so they do not get direct sunlight

I know I not very kind to my battery operated tools and I am very surprised that they last as long as they do

[CapLeaker]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

One thing is correct in you assumption… Do not leave empty batteries uncharged or attempting to charge a hot battery pack. I charge mine right away. As soon as I notice battery degradation, I charge them over night. At the moment think that you’re not giving enough time leaving the battery on the charger for the battery to finish balancing. Balancing takes hours and is not completed when the charger is done it’s charging cycle. Anyway… so far this works for me and never had any problems on any of my 15 LI-Ion battery packs for tools, various brands. I am new to Milwaukee and only got one tool with a 2Ah battery for that. Mostly I’ve got Bosch followed by Dewalt. Heck, my 15 year old batteries for the Hitachi are still working fine. They don’t have the capacity they had, but still they work fine.

[sam_sam_sam]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

Can you identify if the bad "unbalanced" batteries are repeatedly in certain spots within their battery stack? I wonder if the problem is the actual cell or if it has something to do with the battery balancing circuit putting on a constant draw on selected battery group. On the older packs it is not that each single battery is getting balanced, rather the group is split in 2. A 4Ah battery would have 1 group with 2 balancing circuits. An 8 Ah pack would have 2 groups, 4 balancing circuits and so forth. It seems that these single batteries are getting unbalanced where the load resistor for balancing is connected, because the resistor is putting on a constant drain.

There is no certain place in the battery pack it varies but generally it is in middle of the battery pack not normally on the end battery cells on the outside cell but I seen them also have issues but mostly the inner battery cells are the most common issue ( or a quality issue when they are being manufactured ) or keeping them in the car or truck probably dose not help anything either

My old battery packs only have 3 LED's and the Hitachi has no battery display as charge status indicator. I only charge them when they are dead (tool shuts off) or displaying one bar. The new battery packs have like 6 LED's. I've got Hitachi, Bosch, Dewalt and Milwaukee tools. But only got the big batteries for the Bosch.

I have a feeling that when you let a this type of battery get really low and you do not charge it right away and you leave it in discharge state over a period of years it does something to the battery I am not sure exactly what it does but this is what I have noticed with the battery packs that I have

The big batteries 8Ah and 12Ah and the charger are Bosch Profactor. I have some Profactor tools too. Only thing is that the 12AH battery pack needs a small mod to fit in the other regular Bosch tools (cut of a piece of plastic on the battery). Prices are sometimes real good on Amazon and for me the cheapest place to get. I watch until something goes on sale and buy it. For the last 6 months I've been collecting new tools and buy a new tool to replace an old one or something I never had before every month because I am doing repairs / re purposing rooms (built me a shop (mancave) in the basement and a reno at home. Can't afford to hire a contractor. Of course it will be slow, but I am o.k. with that and at the end I've got new tools that I own for other projects down the road and saved me tons of money doing so.

Good luck with your project that you are doing

[CapLeaker]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

Can you identify if the bad "unbalanced" batteries are repeatedly in certain spots within their battery stack? I wonder if the problem is the actual cell or if it has something to do with the battery balancing circuit putting on a constant draw on selected battery group. On the older packs it is not that each single battery is getting balanced, rather the group is split in 2. A 4Ah battery would have 1 group with 2 balancing circuits. An 8 Ah pack would have 2 groups, 4 balancing circuits and so forth. It seems that these single batteries are getting unbalanced where the load resistor for balancing is connected, because the resistor is putting on a constant drain.

My old battery packs only have 3 LED's and the Hitachi has no battery display as charge status indicator. I only charge them when they are dead (tool shuts off) or displaying one bar. The new battery packs have like 6 LED's. I've got Hitachi, Bosch, Dewalt and Milwaukee tools. But only got the big batteries for the Bosch.

The big batteries 8Ah and 12Ah and the charger are Bosch Profactor. I have some Profactor tools too. Only thing is that the 12AH battery pack needs a small mod to fit in the other regular Bosch tools (cut of a piece of plastic on the battery). Prices are sometimes real good on Amazon and for me the cheapest place to get. I watch until something goes on sale and buy it. For the last 6 months I've been collecting new tools and buy a new tool to replace an old one or something I never had before every month because I am doing repairs / re purposing rooms (built me a shop (mancave) in the basement and a reno at home. Can't afford to hire a contractor. Of course it will be slow, but I am o.k. with that and at the end I've got new tools that I own for other projects down the road and saved me tons of money doing so.

[sam_sam_sam]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

Sam: for how long do you charge these M18 12AH batteries for? Just like to see how they did get so unbalanced?

Here we go: I’ve got new 18V Bosch tools with a fancy charger that accepts a Bluetooth module and pairs with the phone. It’s got fancy features that include charge batteries to only 80% or 50% storage mode etc.
So I put the charger on 80% long battery lifespan mode and used one of my older 4Ah batteries. It took about 2 weeks of everyday use for the cells to become so unbalanced, that charging would be completed within 7 minutes, and I couldn’t make the day through without recharging in between.. This battery was dead way faster than the others. So I put the charger back to normal mode and charged that unbalanced battery overnight. Works perfectly again like all the others. My fancy Bosch charger did balance the battery pack. I am wondering if you are giving the charger enough time to balance the battery pack or maybe are Milwaukee chargers straight up garbage? Don’t know. Meanwhile I did also purchase 8Ah and 12 Ah Bosch batteries. As I am starting projects I may take a specific battery pack / charger again to do some testing.

The Milwaukee battery chargers do not have this feature but that is not the only issue with the battery cells the one that are unbalanced are also self discharging even with out the BMS protection board hooked up to the battery cells

Yea you can try to rebalance the battery cells with a battery testing machine but it the battery cells get unbalanced again because of the self discharging battery cells there is no hope for them in the configuration that they are in the original battery pack also even the ones that do not discharge severely by themselves the amp hour results are as follows the new battery cells are 4.5 amp hours the battery cells that are in a self discharging cell pack are like 3.something but each battery cell the battery amp hours are all over the place and to make matters worse voltage curves are sometimes do not look good either

I have been testing some battery cells that were in the unbalanced battery packs and the results are not very promising yet I do not even think I have enough good battery cells to make a good used battery cells

When you have a battery pack that the battery cells are unbalanced rebalanced them and then let them sit for a month or two and do not use them and see if they are still fully charged or not if they are not fully charged anymore the battery pack cells have become unreliable and you have drastically reduced amp hour capacity

I hope this helps you with your questions

One note the battery packs that I originally bought new I have used them very hard in the power tool and more often than not I do not put them back on the battery charger until I have either no more power or one maybe two LED lights on the fuel gauge of course this is not the way to get the most lifespan for a battery pack

When you have a 12 amp hour battery pack that the fuel gauge is blinking one LED light this means that the battery cells are severely discharged it might take 4 hours or more with a 4 amp hour battery charger

But even the RYOBI battery packs have the same exact issue with the battery pack cells becoming unbalanced and I have had to fix a couple of them already I four more of the 1.5 amp hour ones with the fuel gauge on them are the only ones that I fix for myself but where I work at now they have some 1.5 amp hour battery packs that have become very unbalanced or the battery cells are completely dead and are bad that I have fixed with new 1.5 amp hour battery cells

One note about the battery packs that are 1.5 to 3 amp hour do not be tempted to use higher amp hour battery cells in them because the heat sink is not big enough to remove the heat that is generated by using the power tools on them

One note the Milwaukee and Ryobi battery BMS boards do not have balancing feature I wish they did for how much the battery packs are you would hope that they did have this feature

What is the cost of the new 18V Bosch tools with the new features that you were talking about

[CapLeaker]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

Sam: for how long do you charge these M18 12AH batteries for? Just like to see how they did get so unbalanced?

Here we go: I’ve got new 18V Bosch tools with a fancy charger that accepts a Bluetooth module and pairs with the phone. It’s got fancy features that include charge batteries to only 80% or 50% storage mode etc.
So I put the charger on 80% long battery lifespan mode and used one of my older 4Ah batteries. It took about 2 weeks of everyday use for the cells to become so unbalanced, that charging would be completed within 7 minutes, and I couldn’t make the day through without recharging in between.. This battery was dead way faster than the others. So I put the charger back to normal mode and charged that unbalanced battery overnight. Works perfectly again like all the others. My fancy Bosch charger did balance the battery pack. I am wondering if you are giving the charger enough time to balance the battery pack or maybe are Milwaukee chargers straight up garbage? Don’t know. Meanwhile I did also purchase 8Ah and 12 Ah Bosch batteries. As I am starting projects I may take a specific battery pack / charger again to do some testing.

[stj]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

dont put lithiums outdoors,
if you charge them while they are cold they can go boom,
if they get too hot they lose charge/capacity.

i just bin cells that self discharge.
i mostly use lithiums for lights so self discharge is not tollerable in emergency gear.

[sam_sam_sam]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

Update

on these battery pack cells I have put new battery cells in three different battery packs and they all work like they did new I have one more battery pack that I have new cells for that I have left at 3.something after being load tested

Update

on the two battery packs that I bought from EBay I put new battery cells in both of them after leaving the new battery cells fully charged for at least two months or more and still have full charge voltage and four fuel gauge lights

Another battery pack that I still have to put new battery cells in this one has one battery cell bank is at 3.1 and the rest of them are 4.07

So I will have 4 reconditioned battery packs and one new one that 12 amp hour pack each

I am looking for a couple more battery packs that are having unbalanced battery cells in the pack because I have a lot of barley used 21700 batteries that I want to try them in and see how well they preform

There is an update on the taking used unbalanced battery cells 21700 power tool the amp hours are all over the place even if are they not showing signs of self discharging so you really have to test them several times when they have sat for a month or two and retest them again for the best results

I am going have to use the battery testing machine that has the best graphics that shows the results over time where you can move the results line and see the exact roll of voltage of each battery cell use the best ones for the best results out of the battery pack

I have not decided on what to do with the battery cells that have a higher self discharging issue meaning that the battery voltage goes down close to 3.0 volts or a little bit lower than that

I will have to see what kind of amp hours they have after sitting for a couple of months and see if it is worth the time and effort doing this type of project if they are half decent I might build a solar powered LED light fixture that uses these battery cells

[sam_sam_sam]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

I bought two M18 @ 12 amp hour batteries from EBay that have the same exact issue with the three battery packs that I originally had before I put new batteries in them for The cost of the two battery packs from EBay was $170.00 includes shipping and taxes

Between the the two battery packs I should have enough battery cells to make a good battery pack and one not so good battery pack or just use those battery cells in something else

The two that I bought from EBay the battery voltage was anywhere from 3.4 to 4.0 volts the battery has plenty of power to run the impact gun with a load on it so this is good sign that unless it has issues that I do not know about they should be alright

Yes the description that the EBay seller had on these battery packs was as follows
Only three out of the four fuel gauge LEDs light up and the tool works you just can not fully charge the battery packs

On one battery pack I have discharge all the battery cells to 3 volts and put it on the Milwaukee battery charger and the other battery pack I am in the process of discharging all of the battery cells to 3 volts and see if the BMS board has any issues that I should know about

[sam_sam_sam]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

Update on one of the Milwaukee rebuild battery packs the BMS protection board failure this time it just flashing one fuel gauge light no output voltage and the battery voltage is 20.64 so now I bought a couple of battery packs that have the issue with battery packs that only 3 fuel gauge light and will not charge correctly anymore

I was using the high torque impact gun on a project on my son semi truck when it started flashing only one fuel gauge light but no output voltage put it back on the charger and it work again for a few minutes and then the same thing happens again put it on the charger again but nothing this time around completely dead only one fuel gauge light blinking

This battery pack has been acting weird a couple of times before not like this it just would trip out easily but kept working until now

[sam_sam_sam]

Re: Milwaukee M18 HD12.0 (12 amp hour battery pack) unbalanced failure charger refusi

I posted the results on the new SkyRc battery tester that I had bought