Get a Multimeter at Amazon here —

*** USE CAUTION!!! ***

Lithium Batteries can & will catch on fire or explode if overheated! Do not attempt to revive completely drained, damaged, or unknown batteries — only attempt to revive them IF they are still holding a significant charge! (as shown in the video)

MOST “dead” batteries are beyond repair — meaning you never want to disassemble them or replace parts. If this trick does not work, return the dead pack to the manufacturer or recycling center!! DO NOT OPEN THE PACK UP!

Do NOT attempt this indoors!

Do NOT attempt this near flammable items!

ONLY attempt this outside in a driveway or parking lot in case of fire!

If you are not comfortable, do not attempt —- contact the manufacturer for a replacement and/or bring the battery to your local recycling center for disposal.




  1. longest fking vidoe for a SIMPLE FIX …you could have GOT TO THE POINT in LESS THEN HALF THE TIME !!

  2. Good video.. could have done without you repeating yourself for the first 3 mins of the tho !!

  3. I tried to do this fully charged 20v and almost 0v and eveytime go connect the last side starts sparking is that due to voltage difference and can you drain from any battery say fat square 6v or 9v to get enough voltage to jump with 20v as more safer way

  4. Kobalt batteries have 3 prongs pos, neg, and I believe the other is a temperature sensor. I can't get a reading with the multimeter even the known good batteries though.
    multimeter confirmed does work.

  5. I did the same and the battery that will not charge heated. What does that mean. And it still will not charge

  6. I used this tip to get one of my Porter Cable batteries up to around 18.5V and still the charger sees it as defective. Same goes for my other battery which I was only able to bring up to around 16.5V. Any other tips???

  7. Would this blow up an air bed which has the build in plug ?

  8. This wasnt what I was looking for. You can also revive a dead pack the a car battery charger. Ive done it many times over the years. I use to throw them away and get new ones until I found a way to bring them back to life. Only takes them being on the car charger for a few seconds. Then you can use the actual charger for the pack to finish the charge. NEVER charge them on the car batt charger longer then around 20 or 30 seconds at a time.

  9. This is a spot on video. I have done a similar thing by using a variable power supply and adjusting it's output to limit current to less than one amp. You didn't need background music or gloves—-congrats!

  10. Excellent advice had a nearly new battery, that wouldn't charge from the charger. Thank you for your video, saved me e48.00

  11. I have some serious problems with this video. First off, if one or more cells in the low pack has dendrites shorting from the cathode to the anode, you are putting a near short-circuit on that lovely Milwaukee battery. Even if that is not the case, since you have no ammeter in the line, you have no idea what current is flowing. What multiple of C is it? Milwaukee batteries are quite rugged, but if the flow from the pack exceeds the design spec, you can and probably will shorten the life of the Milwaukee battery, which is worth a lot more than an old dead "other brand" battery. Lastly, if you want to try this sort of thing, the correct way to do it is to dig into the pack, detach the cells from the control circuitry, and balance up the low cells to match the rest of the pack. Be sure you know what you are doing, because this can be dangerous, particularly if the battery management system is still attached to the cells. Do I do this sort of thing? Yes, but I have 20 years experience with a variety of battery charge systems, design and cell-balancing techniques. Many of the people viewing this may get away with this approach. Some will not, and the fire that can occur if you are one of the unlucky ones can be spectacular. How do I know this? Let's just say that a balsa wood model airplane can be reduced to ash in under five minutes this way. I want to gently suggest that although this video is quite popular, it is not appropriate for the average user. The risks here are on the same order as installing your own natural gas line, in my opinion. Before you try it, learn about C, multiples of C, discharge rates, and how to balance a pack. When you reach that level, perhaps you should give this a try. The author is very smart, and has a lot of good ideas, but without monitoring the discharge/charge rate, anyone following his advice is asking for trouble.

  12. Can you charge a li-ion battery using a donor battery that has different batteries such as ni-cad or alkaline?

  13. Keep in mind if you put two of the same batteries nose to nose the positive terminals will be on the reverse side so the wires you put on will need to be crossed instead of being straight.

  14. You made a 3 minute video over 8 minutes. Good info, reduce it down to listenable level.

  15. Excellent demonstration and idea! Would cable with higher AWG above 12 transfer faster?

  16. The only problem is if one is completely dead and they equalize to say 10volts each and the low volt cut off is 13.?? Volts then you have effectively ruined two batteries.

  17. What does it mean when charger shows battery charging but it doesnt actually charge the battery

  18. this shows the complete waste of resources that companys make for extra revenue. theres no reason they can not make the charger smarter to do what you just did and save millions of batteries going to waste .. great video !!

  19. Awsome mate , I'll follow your suggestion and see how it goes .
    A very comprehensive explanation, well done .

  20. I feel like this method wouldn't fix the pack fully as one cell could be lower then the rest which would cause the voltage to drop and boosting the voltage like that would charge the other cells back up evenly and leave the other cell lower then the rest and cause the same issue again in a week of 2. I feel like it would be better to disassemble the battery and check all the cells individually and charge the low cell up if one is found before trying this method.

  21. This is a dangerous practice.
    Connecting two packs will result in a high and uncontrolled flow into the flat battery which is exactly what causes the sort of problems that have been highlighted with lithium batteries.
    If you want to try to bring a "dead" lithium battery back to life, it is actually necessary to use a low and controlled current of maybe 50ma. Usable Lithium cells will climb back up to the normal working range of 2.5v – 4.2v quite quickly with even this small, safe current.

  22. Could you also put it on a trickle charger? I tried this and it still didn't work…hoping the cells aren't corrupted.

  23. I tried this with 2 12v Hitachi batteries. The good one had a charge of 11.75v, the one that refused to charge had 9.5v. I used 16 gauge wire instead of 12, hooked up positive to positive, negative to negative. After about 15 minutes, the bad battery had a LOWER voltage of 3.75v, and now when I put it on the charger it makes a bad clicking noise! What did I do wrong?

  24. Thanks for the advice. I had one dead 40 volt battery, and now after trying your recovery method I now have 2 dead 40 volt batteries. Any suggestions?

  25. I noticed what looked like you were jumping from positive on one battery to negative on the other. One battery apparently has its positive on the right side and the other has it on the left. How can you tell in order to place the jumper cables correctly?

  26. I just try the way you showed us it works just as you said. Thanks for sharing this video to people. I subscribed your channel and will follow.

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  28. Thank you for this fix !! I had my doubts that this would work but I did as the video said and amazingly it worked just as your video said !@great video

  29. yuo need aregulated powersuply wit curent limmiter so yo set it for the battery pak like 18 volt en set 300 miliamp conect to the pack en charge up as long as yuo see curent is flowing it is not fully charged.Ivytech 120V 3A 60V 30V 10A 5A Verstelbare Switching Dc Lab Bank Voeding Lcd scherm Digitale gereglementeerde Modul Laboratorium|Schakelaar Energielevering| – AliExpress

  30. Excellent advice had a nearly new battery, that wouldn't charge from the charger. Tried your jump start. Gave it 5mins, and now it is charging from the charger. Thank you for your video, saved me £50. 👍👍👍

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