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Questions about charging dead Lipo's

#1
​Yesterday I was fly my plane and during the flight it ended up in a tree and got stuck up in the branches. I wasn't able to retrieve the plane until today. The 2100Mha Lipo battery that was in the plane was still plugged into the ESC all night long. This morning I was finally able to get the plane down the Lipo was dead.

My questions are, since the battery is dead will there be any harm or long term damage done to the battery if I fully charge it again?

Can draining a Lipo dead like that damage the cells?

Should I keep en eye on it while it's charging and look for signs of puffiness or any other issues with it?

What other signs should I look for if it's damaged from going dead?
 

xuzme720

Dedicated foam bender
Mentor
#2
What is the voltage on the battery? If it's completely flat, the charger won't even recognize it and you won't get it to charge...
 

RoyBro

Senior Member
Mentor
#5
I had the exact same situation, but it was only a 500mAh 2s. But it was so dead that the charger wouldn't even recognize it.
I googled how to revive dead lipos (I can't find the post now) but it said to switch the charger to NiMh and it will charge the LiPo. Only try to charge it enough to the point that the LiPo mode will recognize the battery pack. Then you can finish charging it properly with all the safeties on.

Don't leave it alone when doing this. Again, only charge it by a few volts so that it can be recognized again. Be sure to mark the battery pack to identify it as possibly damaged.

Good Luck
 
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#6
Thanks everyone for all of the suggestions. The LiPo is a 3s and I don't know what the voltage is on it right now. The only charger I have for it right now is a cheap charger for just 3S LiPo's that plugs into the power outlet in my vehicle. All the charger has to tell me when it's charging, or done charging is a red light that flashes when charging, and solid red when it's done charging. I will be getting a much better charger within the week.
 

earthsciteach

Moderator
Moderator
#8
You can recover a LiPo that is below the threshold by charging it as a NiMh battery. Once the voltage is above 9 volts, you can balance charge it. But, you need a programmable charger and you need to keep your eye on it.
 

RoyBro

Senior Member
Mentor
#9
You should definitely consider investing in a programmable charger like the Turnigy Accucel-6. It will charge different types of batteries; LiPo, NiMh, NiCad, etc. from 1s to 6s.
You will need to get a 12v power supply if you intend to use it at home.
 
#10
You should definitely consider investing in a programmable charger like the Turnigy Accucel-6. It will charge different types of batteries; LiPo, NiMh, NiCad, etc. from 1s to 6s.
You will need to get a 12v power supply if you intend to use it at home.
Yeah I'm going to get the Accucel 8 from Hobby King. I'll be ordering it from their US warehouse this week. Can I get the 12v power supply at any hobby store or am I going to have to get it from HK as well?
 
#11
I agree with all advice above, especially the one about a good balance charger: When you recover it the cells may take charge at a very different rate, and while the whole package may, in serial, have a safe voltage, individual cells may be over-charged because they race ahead of the others. When you use nimh charging mode to bring it up, do it with low amps and a little bit at a time and let it rest for half a minute between each go. Do that also when you've gone over 9 V and start with the lipo charging (storage or balance mode). Watch each individual cell closely during both phases. Bring it up to storage capacity first by using the storage feature of the charger.

NEVER leave it during any phase of the charging. EXPECT it to catch fire at any time. DON'T do any of this if its puffed. Store it safely, i e in a metal container.
 

earthsciteach

Moderator
Moderator
#12
Yeah I'm going to get the Accucel 8 from Hobby King. I'll be ordering it from their US warehouse this week. Can I get the 12v power supply at any hobby store or am I going to have to get it from HK as well?
Pete,
You may have a power supply laying around the house that will work. If you can find an A/C wall plug that is within the operating voltage of the programmable charger, you can use that. That's what I did for mine. Its simply a matter of soldering the power plug that inserts into the charger onto the wall charger wires. Its really easy! Let me know if you need more details.
 
#13
If and when you do plan to try to revive it, do as stated before and charge with the nimh setting and start at a LOW charge rate like .2 amps. This will slowly bring it up. if it does reach to 9v then stop it and switch to the lipo balance charge setting. If the charger still does not want to charge it, try the nimh setting again and wait to see about 9.5 v. Just keep a VERY close eye on the voltage and preferably do this outside and in a lipo safe pouch or even something as simple as a cinder block. Now if the lipo does come back to life, run a couple of discharge/charge cycles and charge at half the max c ratting. If it can handle that and not puff up then I would say it should be safe to use again. Just mark that pack so you can separate it from the other packs you may have and keep an eye on it. Good luck.
 
#14
Pete,
You may have a power supply laying around the house that will work. If you can find an A/C wall plug that is within the operating voltage of the programmable charger, you can use that. That's what I did for mine. Its simply a matter of soldering the power plug that inserts into the charger onto the wall charger wires. Its really easy! Let me know if you need more details.
Thanks for the tip. I'll have to see what I have laying around the house to do that when I get the charger.
 
#15
If and when you do plan to try to revive it, do as stated before and charge with the nimh setting and start at a LOW charge rate like .2 amps. This will slowly bring it up. if it does reach to 9v then stop it and switch to the lipo balance charge setting. If the charger still does not want to charge it, try the nimh setting again and wait to see about 9.5 v. Just keep a VERY close eye on the voltage and preferably do this outside and in a lipo safe pouch or even something as simple as a cinder block. Now if the lipo does come back to life, run a couple of discharge/charge cycles and charge at half the max c ratting. If it can handle that and not puff up then I would say it should be safe to use again. Just mark that pack so you can separate it from the other packs you may have and keep an eye on it. Good luck.
Thanks for the suggestion, I'll be trying to revive it as soon as I get the Turnigy Accucel 8.
 
#17
Did it work? Or are you still waiting for delivery of the charger?
I'm still waiting for the charger to be delivered. It should be here on Thursday of this week. Once it arrives I'm going to spend time learning how to use the charger and then I'll try reviving my LiPo this weekend that way I can keep en eye on it easier.
 
#18
My Accucell 8 arrived yesterday in the mail, so earlier today I hooked up my "dead" 2100mha 3s LoPo to it to test to see if it would take a charge like everyone on here suggested. After I got it hooded up I started the charge sequence and right a way the voltage for the LiPo read 9.3v. I am so happy that the battery didn't drain completely. I wasn't sure if it had or not because I had no way of testing it. I'm guessing that the ESC automaticity cut off the power to the batter when the volts got down to 9.3v's. My LiPo is good!!!!

Thanks again everyone for all of the ideas and suggestions.
 
#19
All's well that ends well! At least now you know how to recover the battery if you should, say, put your plane on someone else's roof for two days, ahem.
 
#20
Goody good. Makes you wonder what the manufacturers do. Presumably they have to charge them from flat (or are they partially charged just from chemical reaction? Hummm).