Safety tip. Hook negative to negative first. Then positive to positive. Don't do both negative and positive same time on one battery as it leaves the leads both positive and negative free on other end of wire. If those two wires touch you are gonna short it out, cause a fire or sparks gonna fly. Doing it one polarity at a time will prevent a short.

It worked!!!! Bro that's a $250 battery you just saved. Thank you!

I had that same issue, I did what you did and it worked GREAT thanks for the information 👍

I’ve had my Milwaukee charger right out of the box flash green/red so I called them directly & they told me sometimes new batteries go into a “sleep mode”. They simply suggested this upon the initial charge & should work from there on in! Gonna give this a try this weekend!!

The jump start worked for me on a Bosch pro core battery. Thanks pal.👍👌

Worked for me💯💯💯💯. Left a light connector on it for months. Could of turned on and i never knew. Tried to plug it in and got the red and green flash. Did exactly what you did and it sparked for one min. Tho i was using 18 Awg wire which is WAY to small but only did it for 30 seconds before the wire got warm. Then tried to charge battery again and its alive💯💯💯💯

This worked for me. I have an M18 that was showing one bar, would not work in tools but showed charged on the charger. I used this jump method, did not seem to bring the charge up. Put battery it the charger. It was red for a second, switched to green, now the battery is at full charge! Thanks Mate!

I just tried this and it seemed like it didn’t work. Only one flashing bar and got the green light on the charger. After reading one of the comment where about freezing it and hitting the battery to break up the lithium I tried giving it some medium to light taps with my hammer. It worked! My battery seems to be working fine now. Thanks for the tips

I just did this. Phew!! Saved a C-note. I just poked the braided wire straight in the sprung clips. It was less secure but it worked. Thanks for a good hack.

This works good for any battery powered tool. Super useful to know if your going to always be using battery tools. I've had to do it with everything from my Milwaukees my dad's DeWalts and even when I brought a cheap heart. After jumping it should charge. If it doesn't run it dead and throw it on the charger.

This worked !!!!!! Thanks bro you saved me 175 bucks ❤

You're cell pairs are most likely unbalanced. Where one block out of the five has dropped below a critical threshold voltage, ie 3.00v or lower. If you have access to a power supply and you're able to break the battery apart to find the low block and charge it individually. I've had great results with this method and have brought multiple batteries back to life this way. What seems to happen is the BMS monitors the individual voltage of the 5 cell pairs and for whatever reason if they're not within a certain threshold of each other, like .5v, or what not the BMS will not allow you to use or charge the battery

Take some fine grain sand paper and wrap it around an ID card or an old credit card and lightly sand in between the metal prongs on the battery. It's worked for me more than once. Them things get dirty and the metal can't make contact because all the crap that builds up on the prongs. Worth a try before shilling out a predatory amount for a new battery.

Jump start worked for me. Thanks!

Worked like a charm!

Charger is lighting up green due to one of the three banks of sells being lower than the other two. I recently saved one by pulling the pack apart, identifying the bank with the lower voltage and connecting a proper lithium charger to it. It brought the bank back up to the proper voltage and has held its voltage so far.

Thanks bro! Didn’t know the reset feature and saved me some money!

No joke I just did this on one that's from 2012 and has been in my pole barn for over 5 yrs dead because I had a different brand but recently switched. It would charge but only half way at first so i charged each cell individual with jumpers on 18650 battery charger so each cell hit 4.08 volts but now it takes a full charge. I haven't yet tested how long or fast it'll drain but it's been holding charge now for a couple weeks.

Can I jump start a 40 v battery with another battery that has lower voltage? I have a greenworks battery where the charger is blinking red

Cool thanks charged for 10 minutes with a good battery then it slowed charge to work. One thing I did see was one was at 17 volts one was 18 volt so looks like imbalance so I'll run it till it stops and change again Absolute dedication absolute.

Cool idea. Watch from malaysia

Today I successfully replaced the PCB on the Milwaukee M18/5Ah battery. When I soldered all the contacts and pressed the control button, none of the LEDs lit up? But when I put it in the charger the battery worked like new because the Milwaukee Intelligent Charger unlocked the battery!

Thank u bro u just save me some $$

Please be careful doing stuff like this. Voltage differences when connecting batteries like this will make them want to equalize immediately. This can result in sparks, shocks, LOTS of heat, melted wires, fire, damage to both batteries. It would be a much better approach to understand WHY your battery won't charge. Do you have a dead cell? Is the pack below minimum voltage? If a cell is unbalanced, try to revive it individually, if the pack voltage is too low for the charger to accept it, bring it up slowly with a low amperage float charger (like a motorcycle battery tender), once the pack gets around 13.2V, try to charge on the stock charger again. EDIT: in my case, i used some crap chinese flashlight add-on to my M18 battery. I left it on there not being used for 4 or 5 days and found a vampire draw had brought my battery down to 10.2V. The float charger worked like a charm to revive the battery.

Excelent, salvè mi bateria. Gracias por este video

I jumped mine with a couple razor blades and a battery charger for a car turned it on for 10 secs and the first light of the battery came on then I put it on its charger and it started charging like normal lucky I guess lol

Just want to know could i jump start my 9.0 with my 1.5 sad as it is to say thats all i got lost my 4.0 ajd 3.0 is in the pawn with my toold 😥😢

Did it fit a 6ah. Worked. Just saved myself $196.

Does this work to fill a battery that will only charge to 3 red lights instead of 4.

My battery was fully charged at one point, then suddenly it was blinking 1 bar. So I tried charging but the green light stayed lit on the charger just like yours. I jumped mine and it says 3 bars now but still won’t charge. I’m assuming once the battery is dead, it’ll be a brick. Did you drain yours and tried charging?

I have two 5 Ah batteries exactly like yours, both had 0 bars and showed green on a charger but wouldn't charge and wouldn't run a drill. I opened up both cases. One battery had a low cell so I charged it up to 3.7 volts alone and then put it on the charger and it charged it up fully, it took about 4 hours to charge. I don't know how long it will last, it probably needs a new cell. The other battery had 2 low cells and one was actually a negative or reverse charged to 0.5 volts negative. Again I charged each one separately to 3.7V and then I could put it on the charger and charge it up to 4 bars.

This worked for me. I only had the jumper wires on both batteries for 1 second and it was enough to bring the dead battery to life so that it would charge again on the charger

Did you ever get your battery working

Holding the indicator doesn't reset anything on the battery. It flashes out a date code and other battery stats like how many times it's been charged. Supposedly, it also flashes to indicate a problem, but they won't release what the codes mean, so it's anybody's guess.

❤❤❤❤

Heard this works with a 9v battery for 30 seconds and you don’t have to risk your working battery.

I used a car battery charger and it worked

Does anyone know the freeze it technique. They usually don't change because the lithium in the battery has gone hard. Freeze the battery in a plastic bag for about 2 hours then drop the battery 2 or 3 times too break up the lithium then try charge it.

Might be worth pulling it apart and checking each cells voltage, maybe one is dead or faulty, u also have to get the battery to a certain voltage before the charger will charge it. I would like to see u revisit the problem and see if u can finally fix it.

at least use a resistor and bring the voltage up slowly, fast charging cells that are below 3V can be very damaging to them. Or use a current limited power supply and keep below 0.3A until minimum voltage which is 15V in a M18. if flashing red led will need MIlwaukee charger to unlock it.

I don't know how your battery charger works, but my Milwaukee charger shows green when the battery is charged, red when it's not up to power yet ?

Take the other battery plug it into the charger take it out and put the ba done back on always worked for me or take a 9vt battery and do the same thing u did with the other battery to jump it then charge it

By the way the problem may not be at the battery sometimes it is from the charger

You can do the same to your car with a decent charge, fires right up

And watch it blow up 😂

This is not a test. This is not a test.

Just tried this wires started burning for some reason

mines still don’t work

Did it for 10 seconds on a fully charged battery now the dead one takes a charge just fine

Were any children harmed in the making of this

Made me nervous watching this, you should have tapped up your leads. I thought they would touch and short out.

Battery is gone finish!

That wont fixit my broda comon!!

I tried this but the wires are getting really hot it started melting the rubber off

How to start a fire 🔥🚒 😂

I did this and the hot wire started cooking

What the # is this

What when i have not old battery? Milwaukee is expensive. Problem with battery it's a joke.

Did not work broke both of my batteries

What a failure 🤣

Maybe it's your charger

This shit didn’t work I even burned my thumb doing it better off just buying new batteries

It doesn't work.

It flashes red green red green. Not just solid green

Supposedly not supposbley

Those are ghetto milwaukee batteries