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M18 6ah Battery - Temp sensor issue

DozerDan82

DozerDan82

Master of the Universe!!!
Joined
May 21, 2020
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1073
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Back in August I grabbed a 2pack of High Output XC6 batteries. The other day I took the one off the vacuum to use on my saw- and it was dead- NBD just charge it. Won't charge. Red light comes on, then right to green- as if it is fully charged. Hit the button on the battery and it flashes at me, according to the internet that is a temp issue. But the battery was not used hard, and was in the house so no reason for it.

I am sure I can dig up the receipt if I needed to, but also pretty sure Homo Cheapo is gonna tell me to take it to Milwaukee.

Anyone dealt with this before? Any quick fix to try, a reset perhaps? I have lots of other batteries and never had an issue like this that did not clear up itself, I have had hot batteries not charge until cooled down etc, but this is just like its reading wrong. It has charge in it, because I used it to jump two totally dead ones enough to charge the other day.
 
A0086F3A-EB47-4440-8A33-8F461CC1C6CF.jpeg
Try this. You only need to connect it for a second and it resets the battery and cures a lot of charging issues. Jump it with a good battery.
 
Fullsize80cherokee said:
Try this. You only need to connect it for a second and it resets the battery and cures a lot of charging issues. Jump it with a good battery.
Click to expand...
I can try that, but it should have a charge- being that I just used it to jump two off brand dead dead ones to get them alive enough to charge. I will jump it from my 12ah and see what happens.
 
DozerDan82 said:
I can try that, but it should have a charge- being that I just used it to jump two off brand dead dead ones to get them alive enough to charge. I will jump it from my 12ah and see what happens.
Click to expand...
If it has charge…. Maybe try running it totally dead….. then try again?????

If you don’t have “pro rewards” at Home Depot…. You’re doing it wrong!!!! Never a receipt needed!!!!
 
HD will probably warranty it for you. Had a couple of Bosch bit the dirt and lowe's did it now problems.
 
I had a battery issue right out of the box with an M18 tool. Milwaukee took care of it quick and easy. BUT...it is ground only for batteries!
 
Won't die bc the tool can not recognize it, nor the charger from the fault. So with the meter, the neg is the one corner, the + is the other for the tool, but for the charger the + is no active. They did some trickery here, as there are also 2x + terminals for the battery. According to my meter this is fully charged, yet will not work or take a charge. Very odd.
 
I had this issue once, I used different charger, and it worked ok.
 
DozerDan82 said:
Won't die bc the tool can not recognize it, nor the charger from the fault. So with the meter, the neg is the one corner, the + is the other for the tool, but for the charger the + is no active. They did some trickery here, as there are also 2x + terminals for the battery. According to my meter this is fully charged, yet will not work or take a charge. Very odd.
Click to expand...
Put a light bulb or a resistor in between positive and negative. Those dont care about faults.
 
Fullsize80cherokee said:
A0086F3A-EB47-4440-8A33-8F461CC1C6CF.jpeg
Try this. You only need to connect it for a second and it resets the battery and cures a lot of charging issues. Jump it with a good battery.
Click to expand...
This and one time with a DeWalt battery I had one that wasn't sitting properly in the charger. Make sure it is making good contact with the pronge and is fully seated. I was looking at a 5AH battery that was only good for a paperweight there for a minute.
 
I had a 12.0 that would only light up 2 of the 4 lights on the battery and the Milwaukee charger gave the bad battery blinky code every time I tried to charge it. Battery was out of warranty with a price I didn’t like for out of warranty service or it would have been sent back.

I took it apart to see what there is to see. It’s already garbage so I can’t break it more right?
Worst case I just salvage some of the cells to use as singles.

It looks like there are 5 groups of batteries with 3 cells in each group. The battery groups were way out of balance ranging from 3.53V to 4.09V.

IMG_5992.jpeg

IMG_5991.jpeg

I have an RC car battery charger so I rigged up a connector for it to some alligator clips I salvaged. Clips are too big and are pretty sketchy when hooked up, but that was the first thing I saw in the garage that would work so it got used.
IMG_5996.jpeg

I charged each bank of 3 cells individually so had to run the charger and readjust the clips 5 separate times. Now they are all charged back up to a similar Voltage. The 4 lights all come on when pushing the test button. Eventually I’ll see how it does on a tool and if the Milwaukee charger will accept it once it gets run down.
 
The battery ran the fuel leaf blower pretty well. I’m calling it a success.

This is where I hooked up the charging leads for my 12.0, but check yours if attempting with a meter before hooking up so you don’t let the smoke out.
IMG_5997.jpeg

The order the charger clamps got hooked up and polarity.
A+ 1-
1+ B-
B+ 2-
2+ C-
C+ 3-

Time will tell if any of the cells are toast or if it just needed to be balanced. Only cost on my end was the pigtail to plug into the charger so this was worth messing with considering the cost of a new battery.
 
Keep in mind though that a big part of the job all that circuitry does is protecting the battery from thermal runaway, and bypassing it/doing weird tricks trying to 'fix' it stands a decent chance of causing thermal runaway.... i.e. your battery explodes. At a minimum would strongly recommend doing anything with the guts of a LI battery outdoors away from anything flammable you care about. Yes, this is probably paranoid, but is the risk worth it?
 
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