Thanks bro I repaired my sick battery after seeing your helpful videos,

Thanks for giving me the courage to open mine up. found a bunch of rusted off tabs and a few dead cells in my two broken batteries. Saved me from buying replacements. Glad I had a few 18650's stashed away.

Great video, thank you!!! : ) Don W., Ohio

What kind of wire?

Fantastic video! I bought a BD 20-volt drill and battery from eBay for $28. They both appear to be brand new. I was disappointed when the battery blinked red. I tried your trick and jumped them for a couple of minutes. Viola! Works great. Thank you very much.

I literally just opened a new one of these and it did this on the first charge…. Ridiculous brand new and it won’t charge

Amazing bro! I bought a “new” drill from someone on fb market place and when the battery did the blinking red thing I convinced them to refund me half the money. Then a KZbin search brought me here and with a $6 9 volt battery I was able to jump start the “broken “ battery and now it’s charging!

Fantastic! Jumped my battery using safety pins taped to the top of a 9V battery for about 3 minutes. No more flashing red, looks like it’s charging! Thank you!

Doesn’t worth it you can burn your house. Then the insurance won’t pay for the damage!!!

Excellent demo. I have the same issue of the battery, and I will try to fix it. Thanks

well, not something, I am a woman who does not solder, could do! But at least I have a partial answer. I have two new Black and Decker hedge trimmers, dated 2021, and both flash red. Suggests based on this that they have sat around uncharged for too long.

Bruh this 4 years old and mines did this after 1 charge wtf... So I jumped mines with a car battery charger and now I got the green light charging.. 👌🏽

I just started hitting my battery a couple of times and bingo,started charging correctly!

You should have jumped that battery in the first place instead of pulling it apart! Secondly you don't really have to wait 15 min. before trying to charge it. I have found 5 min works sufficiently. But that's me.

What can of wires can we use to jump the battery’s ? Where do we get the wires

Tenho uma dúvida, eu necessariamente preciso desconectar os fios para checar se as baterias estão funcionando? 😅 Desculpe minha ignorância

You went through all that trouble to unsolder the cells from the battery management/charger board. And you would have been far better off to "jump" each cell individually (with a voltage and current controlled power supply) which would also give you an indication of each cell condition when you did that. You could have also measured the voltage across each cell without taking them out of the circuit for an indication of charge state. You didn't need to do any of all that just to try a 20V "jump" charge either. HAHA. Safer too, if you had one or two shorted cells putting that 20V on the system (with only 2-3 cells "working") could result in an overcurrent disaster to BOTH battery sets and your test area. Take care, and try that approach next time. -SG

What do I do when the cable that connects to the battery isn't going in when pushed. Should I remove something from it or plug in a specific way, or maybe it needs more force. I'm worried it will break.

I've had so many NEW batteries going bad only in a matter of months. Cheap lithium? No idea what the issue is. Seems like engineered obsolescence to me.

Made the jumpers, hooked the bad battery to the good one, waited 15 minutes, and it worked! The problem battery ( which had been sitting around uncharged way too long) is now taking a charge. Thank you, you saved me from buying another battery.

An even simpler solution (at least one worth trying first) is pulse charging: Put the battery in the charger and then plug the charger in and out from the outlet a few times for ~5 seconds at a time. I tried it recently and it took about 5 rounds but then it started charging on its own

Funkade direkt Tack

Came out of the box doing this for me. Didn’t realize for a year because didn’t need it. Now I’m probably screwed (pun intended)

So is this a version of the 'modern' car battery chargers that will not charge a very low battery, not turning on under those conditions? (I assume a 'save the public' safety feature so the two terminals can't spark or burn up the charger?

Thank you! It worked for me.

My charger is flashing red WITHOUT any battery connected!

another method is to get an adjustable generator and slow charge each battery to around 3.5 volts...and then charge the whole thing up normally

Just jumped my 20v battery successfully with a 12v laptop charger because I didn't have another battery.

Gracias amigo, si yo tambien cuando me paso, y si pense que fue porque se bajo demasido la carga y el cargador es muy lento, y es de muy poco amperaje y no alacanza a meterle carga cuando estan tan vacias, asi que necesitan un pulso con una carga muy fuerte para que reviva y el cargador a partir de alli pueda recargarla. Hice lo mismo que tu, con una bateria de 3 amperes solo le di un pulso de 10 segundos y listo cinecte el cargador y con eso fue suficiente para revivirla, saludos...

Now my battery is working again! Thank you so much pal!

I keep a drill in my my car all the time, i guess after months without charging it, the battery will drain and that causing the red flashing when plugged

Thanks a lot. I had the same problem, and i jumbed my battery, who doesnt worked before, with another battery, and now the battery works. Thanks for the video, it was very halpefull.

Thank you, I took a similar approach. I purchased a cheap (Amazon) variable DC power supply (Kaiweets KP-1010). I just connected the + and - which are labeled on the battery and slowly moved the DC supply towards 18v and no more than 2 amps, for less than 30 seconds. Voila the battery is now charging with a green charging indicator.

This works for me. Without disconnecting the batteries from the board, I just had to give each of the series a small boost for 10 seconds with another 4.2v battery and it worked.

So the smart thing to do is jump it first. Do not disassemble. Would be a waste of time

Thanks a lot this is very helpful, I jumped it for only 1 min and it’s working now 👍🏻👍🏻

Alls i did was stick my battery back in my hedger and run it for 1 minute and plugged it back into the charger and its charging no need for all the mumbo jumbo you did

Sucks cause mines is new

no matter if i jump it or force charge it the battery voltage will not move.. is the batteries dead?

Hi, for jumper battery, is it must be the same as the voltage and current ?

And this is why I will NEVER buy another Black and decker. My mom's did this after 3 months. Mine after about 8 uses. Clearly there is an issue that they arent fixing.

Seems best not to jump with more than 20 volts. I hooked up two M12 batteries in series and the volt meter read 24 volts. I jumped the Black Decker battery and the wires got extremely hot. Charger is now blinking green. Thanks for sharing.

Very helpful - just brought my 20v batteries back to life.

Additional tip: Tie a knot at the end of the wire so it's on the inner side of that hole. In case you accidentally tug it, it's not gonna rip out the soldered wires :) Thank you friend!!!!!! No more wasting batteries! REDUCE, REUSE, RECYCLE!

Excellent!! Now as someone else has suggested, I will troll the recycle bin at the big box stores for ZOMBIE batteries!!!!

What kind of wire do you use to jump the battery from one to another? 🤔

Awesome! Jumped mine with a 9V battery from my smoke detector. B&D is sending me a replacement as well.

perfect for the dewalt shop vac

Wire jumped it for 10 seconds and it was good to start charging red light blink stopped to normal charging

Laptop battery had clear written warning on top to disconnect the battery before adding or removing parts!