Milwaukee Battery Won't Charge (How to Fix!)  

Sounds like Milwaukee needs to fix that issue not the consumer.

Thank you for this information. It saved my battery and it's so easy and simple. I'm glad I keppet my battery charger after I quit vaping. I'm basically a certified battery doctor now. Thank you.

Just fixed an XC8.0 with a $30 "MiBOXER 18650" charger I had lying around from flashlight games. Definitely important that it's a current-limiting charger, but at 200mA nothing even got warm. Thanks for the video!

Great info. Just done a 9ah and a 12ah both with same issue. Both are going fine now. Cheers mate

Thank you for sharing your knowledge! I learned a lot from this ! I really hope fixing becomes more popular it helps people in more ways than just fixing something!!! Thanks again 👍

I ordered the same charger after watching this video and fixed my 8ah Milwaukee battery charging 2 cells at a time. Thank you for this video, you saved me and others I will help in the future if they ever get the same issue, a good amount of money in the long run.

Outstanding, thank you; easy to follow and makes sense!!

Great video mate it was very clear and easy to follow. Can't wait to fix a couple of faulty batteries I have here.

This just saved 2 batteries for me. a 12 and an 8 ... could have saved 2 x 9ah if i had known earlier .. Awesome job mate.. well done

You're a life saver! gonna try this today!

Thank you for sharing this video! It helped me save 2 HighOutput 6.0 battery's

Very good video will save DIYers a lot of money including me thanks for the information

Great video! Thank you so much. I'm now charging the second low bank.

Thanks! Fixed my 12.0 and about to start working on a Bosch battery

Great video! Thanks so much! I am regretting throwing away two of my 5 aH Milwaukee batteries that I couldn't get to hold a charge. Now I know!!!!

I had to order the charger from aliexpress, but once I got it, hooked it up and saved 2 batteries. Thank you for the video.

Big thank you, I was able to save my battery with you help. I think the problem is when you run a battery down on a tool until it has no charge left this is what happens.

Very helpful, thank you!

Great video I have been looking for an easy way to balance a battery pack you found it thank you

What's causing that problem is that the internal resistance of the cells are getting mismatched and the bms in the Milwaukee battery is failing to bring them close in voltage. To make matters worse, having higher amp hour in the battery and high amperage draw from the tool, increases the probably of that happening. DeWalt doesn't have that problem cause what makes the cell balancing is the charger itself, not an internal bms in the battery.

Thank you for another great video.

Good video. Great explanation.. only thing I could suggest is link in description on the charger you used.

worked like a charm on my unbalanced 8 amp hour m18. working on a 9 now... wonderful

Awesome video...I just ordered the next available version of the charger (Opus C3400). What guage / type wire did you use for the leads?

Thanks for this vid! I bought the same charger to revive two 8.0s. It brought one of them back, but on the other one, all banks read 4.19v but only 3 of the leds light up.

This is excellent. I've got 3 high cap batteries that only work for half their capacity. I'm going to give this a try. I've also got a coworker facing the same issue with his that I'll see if I can fix.

I have an old RC variable lithium charger that I tried with on one of my 8.0 amp batteries that dies very quick but then charges almost immediately. Flashing light recently that won't run a tool and shows green full charge on the charger. I was able to bring up one bank that was below 2 volts. This was a life saver! Thanks for the video!

Great video, good info im ready to fix 2 of mine that are doing this.

Those hex bits with the holes in the center of them are referred to as tamper-proof torques so not just any wing nut can remove them. Hehehe Hey brother good video informative educational I think some of us might have learned something today thank you keep up the good work

Great video. Thanks.

Thank you for the video 👍

I had 4 of 5 cells low. Charged all of them individually and the battery is like new. Thank you

Thanks man. I am so going to do this.

Very cool👍thank you Sir

Thank you mate - good ide to use home battery charger. Just one question - for how long this has solved the problem for the batteries? DId the problem showed up again ? If yes - when?

The reason you are having a hard time getting readings is because the HD 12's have a protective coating. I noticed that my 9.0 I could just touch the banks and it worked fine. If you just tough the banks on a 12 it won't work because of that coating. You have to scratch through the coating first. Its very annoying for charging with the Opus as well. That is the same charger I use as well. I have to get the leads to dig in so that I can start the charge. It irritates me to no end that Milwaukee continues to have this issue with such incredibly expensive batteries. The solution to this issue is for Milwaukee to include a BMS that can actually balance the batteries. They claim that it can balance the batteries but it doesn't. And I feel that this is designed this way so people can buy more batteries of course. I have batteries that are from 7 years ago that still work fine. The charge isn't even that bad tbh. But they have gone out of balance several times and I fix them every time it happens and mark each battery when it happens so I can keep track of how often it happens on the battery. A true BMS system that balances batteries would look at each battery and make sure it is at the correct voltage at the end of charging. Vs milwaukees which likes to stop whenever one bank shows roughly 4.1v leaving the rest uncharged. And when milwaukees BMS system shows around 3.2v or so, it shuts down the tool. This is exaggerated when one bank only gets charged to 3.6v when the rest are 4.1. Even though most of the batteries are full, you will only get the life of the battery bank that is lower.

I think you need a DC power supply. Much easier than Jerry ringing a charger. It turns off just the same when the voltage is achieved. I have the NANKADF 30V 10A its very useful around the shop.

I bought 3 12.0 batteries and they all did this. None of the other milwaukee batteries have done this. Thanks for the tutorial i gotta try this

Genius diagnosis & solution. I have a wild thought. Could we simply connect every 4.2v bank in parallel and let them equalize themselves? My XC 8.0 has the same issue too !

Thanks bud I tried this and it saved my 12 amp battery. It took about 24 hours to get my battery charged back up. It was totally dead

Best video on this...

Great video pal any links to a suitable charger for us across the pond 😂 thumbs up 👍

Also, what you referred to as a Bank are just batteries in parallel. The more batteries in parallel the more capacity Connecting multiple batteries or what you refer to in this video as banks increases voltage. Easiest way to explain this especially for those that may not understand with the lithium batteries is showing here is think of car batteries if you get 12 V batteries that are 100 amp hours and you connect them all the positives together and the negative to negative you’d have a 12 V 400 amp battery but if you went from the first battery to the next batteries negative and so on on both sides you increase the voltage to 48 V, but your amperage would stay at 100. You would referred to this battery as a 5S3P. 5 cells in series 3 cells in parallel.

Thank you

I have 2 12s and a 9 that needs some CPR. Gonna try your method and see if they come back to life first.

This Man deserves a new Fluke, or at the very least, a new Klein MM. 😊 I am going to try this on a couple of my M18 XC batteries that give the ‘Christmas lights’ when placed on the charger, as well as a couple of my M18 8.0 HO ( expensive ) batteries with the full charge showing only 3 bars. I have a NiteCore charger that will charge LiIon batteries up to 21700 in size, so will try this. I have scrap dowels lying about, so will give it a go. I’m thinking the NiteCore charger will suffice?? What say You? Much appreciated! 👍

After you set the charger to “charge” will it just auto charge to the correct voltage or do you have to keep checking and pull off at 4.2 volts?

What i do is put it on a tool that has high power draw like a leaf blower and run it for a few minutes, after they discharge a bit, it will take a charge easy

The spring slots needs to be cleaned with contact cleaner. A little bit of fine sandpaper.

If the voltage of any cell, pair or trio approaches 4.2v, the Milwaukee charger stops charging. I like most the "defective" Milwaukee M18HD12 batteries that I get for free or buy for 10-15% of the new price that cannot be fully charged. Cheapest and easiest repair. With the external charger, I equalize the cell voltages and put the battery back in the charger. Greetings from Switzerland

Keep your sales receipts-HD warrants these batteries for up to 3 years from purchase. Just took a M18 6.0 back that was 3 months old that wouldn’t charge anymore, gave be a brand new one.

Dumb question, bit can't you jump these by doing what you have there but instead using another battery? Like when you jump one that has flashing red & green light?

This has just happened to one of my 12ah batteries, not even 2 years old but i didn't register it for warranty. 220 quid battery should not do this. thanks for the video.

Once you balance the cells, what keeps the problem from occurring again- can the bms circuit be fixed so the battery charges properly on its own?

Can you put leads from the milwaukee charger if you don't have the fancy charger?

I have a 12Amh battery that is just out of warranty and it just plain died after just a few minutes on my blower. Charger won’t recognize that the battery has been put on to charge and not lights on the battery will light up. Any hope for this battery?

Well ill be darned! I actually HAVE one of those fancy chargers! When i started watching, i instantly felt doomed as soon as i found out i needed to buy a special charger....then you rolled out old faithful as my wife and i call it, and began showing us the way! I cannot even believe it! Thanks foe the video, and yeeehaw! Now mine will be the only gd damn battery it wont work on Haha! As always, hope for the best, always prepare for the worst!

Gday mate, I have a 12amp in the same situation. Will give it a crack and see how I go. Cheers

Could I use the c3400 cant seem to find that model you have anywhere

Hey what settings should i use with a RC car charger ? 7.4V or 11.1 ?.. & charge at what ?

so I couldn't buy the exact battery charger but I got one pretty similar. I have been charging at .5amps but it is really slow.. mine can go up to 1.5amps and is there a reason not to go any higher than .5 amps? I have 8 batteries to go through and I wonder if I can save some time by charging them a little faster..

Thank you! I got two batteries with this issue, very frustrating considering how much you pay for them

I had a bank (M18 12AH) @ 3.67 and it took almost 12 hours to get just below 4.2... Is that normal, in the video you mentioned an hour? Great video by the way, thank you.

Could I do this to any old M18 battery to "refresh/recharge" it?

Good video i just need to buy the other tools to check the battery

Realistically, how long can this prolong a battery's life? I've probably owned my battery for less than 3 years but I didn't think to keep the receipt since I generally take meticulous care of my stuff. I'm imagining having a hard time trying to get warranty help, so I'd like to go this route, I'm just unsure how much longer I can expect to get out of my battery even after doing this. I would hate to do this then just a few charges later, have to do this again, and again etc. Thanks in advance!

I’m sure someone must have mentioned it but they’re called security bits just in case.

Does that charger automatically set itself to 4.2 or do you have to manually set the voltage? I just bought a 12amp battery and it’s doing this exact same thing

Interesting. Would it be the same result if you would discharge the cells with higher voltage to the level of the lower and then charge the whole battery full with the milwaukee charger?

How about the 12 volt batt's? Great vid thanks.

You are a righteous dude.. thx for taking the time to make the video.. now if you could just tell me how to get my Parakeet to eat my diarrhea all would be good 😂😂

So do I have to do this everytime when I charge my battery? Seem like it's not worth having a battery power tool.

How do you automatically get 4.2 if you set it to charge up to 5.00 mah? Also, I'm lost on polarity. So, it looks like the battery starts on negative on bottom left and ends on positive at top right. Series. So when you charge band 2 starting at bottom, should you flip from positive to negative on the next jumper to bank 2? And swap going to the next? And swap against until you end at top right positive? I saw your second charge and you switched the left negative blue 12v ring hole wire to the next one in line. I'm confused. Anyone know how to explain this better? Thanks

thank u it works but what i use to charge it is a usb charge port

Ah man I threw 2 huge m18 XC batteries in the trash last week before I saw this video. They were both showing green full charges but not lighting up. Same exact issue. Had I saw this video I could've easily fixed it. Bummer

Will this then make it able to charge the batteries in a normal charger after you do this?

Nice trick Fixer2u 👍 Help me undestand how it worked. I havent got charger but I just save my 5Ah with 2 wire 1,5mm2 connected from one batterie fully charge to an oder one over discharged for 1min without opening anything. After that the Milwaukee charger works. The batterie has just 3 months .. ( I lost the garanty) Don you think using this methode with different battery capacity could be risky ...? Thanks for your works from France !

Do you know of a smaller cheaper one because this charger is no longer available

What type of charger do I buy for the lithium battery

Coloured tester leads are best 😂

what i did was , i took another battery and ran jumper wires to the pos and neg terminals and let it sit for some time and the battery actually started to charge , but i do have others with problems and 1 i tried this with but it still failed with a flashing light and green on the charger, which im suspecting a bad board. thanks.

Hi ,where i can buy that charger you used to recover that battery , please thank you

Battery Issue. The Fix is Place a Jumper from bad battery to a good charged battery. Pos + to Pos + and Neg - to Neg- terminals wait for about 15 minuets for battery to equalize. problem solved. both batteries are ready for work or charge to full

is this something that affects Milwaukee batteries only, or do other brands suffer from this problem?

Have you tried this on different brands? I guess it will work, I have 2 bosch batteries doing the same

What type of wire to do the positive and negative clips?

Im scared to do it how bad will this will explode when wrong connection?

Okay what if my batteries stone cold dead? How could I fix it then?

How about a battery that shows no charge and flashes red/green? Tried multiple chargers.

What about batteries that will not charge and have blinking red/green lights?

My hd 12's are the only batteries from milwaukee ive wver had this problem with

Can i use this for my dead 9.0? I tried using the juno start method several times to no avail

After trying this, my battery with 3 bars now has nothing (flashing indicator) and displays a green light in the charger, does anyone have any recommendations or solutions? Did I do something incorrectly?

Couldn’t you use another batter and jump banks together to let them balance themselves out

My 12ah battery stop charging too . I like to fix it but I don't have any of those tools to make charge again. So right now I have this battery to show-off when people want to brag about there batteries 😂😂 they say good things about their batteries I tell them that I have a 12ah battery too😂😂.

Batteries are not meant to be discharged completely how to resolve this issue is never let a battery go low I have batteries that are 15 years old and work exactly like new never had a battery issue never let a battery run low just like a car battery it will destroy it.

I don't have time to go through 300 comments to find the answer I'm looking for 😆 and sorry if someone asked. What gauge of wire are you using for your jumpers? 12 or 14 thhn?

Looking for this charger but doesn't say 21700 cell type? It's that a problem

Hope it’s works on mine

I just found a better way to fix it. I buy a new one then return the one that doesn't work and get my money back. Did it twice already at home depot