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

[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

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

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

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

[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

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

[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

[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

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