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Batteries 12s stick pack

fran11784

Active Member
Goblin 380 Supporter
I accidently left a 3000mah 12s Pulse stick pack plugged in to the ESC on one of my birds and completely drained it. It shows .5 volts in each pack. Before I toss it in the trash, has anybody ever saved a lipo this dead? Is it even possible? Thanks
 

Tony

Administrator
Staff member
It is possible, however it can be a little "iffy".

Disclosure: DO NOT DO THIS! This is for informational purposes only :wink:

You can try to jump a good pack onto the bad pack to help "jump start" the cells to get them up high enough a charger can charge them. I have successfully done this on a balance board before, but know, it can burn traces in your board. The other way is one cell at a time. If you have bread board jumpers (male), you can put one in the negative, and start jumping one cell at a time.

When you do this, Or when "I" do this, I plug the negative in, them I plug in and immediately unplug the jumper on the positive side. This is to stop it from charging the cell too fast which can cause puffing.

It's dangerous, it's risky, I would do it outside on gravel or pavement and I do not suggest anyone do this. But, it's also a very expensive battery pack and sometimes, especially now days when a dollar is worth 10, it's worth it to ME to try to save a $200 pack....
 

fran11784

Active Member
Goblin 380 Supporter
O well, its not worth it to me to even try unless it was something simple. Toss it up as a stupid mistake.
 

Admiral

Well-Known Member
O well, its not worth it to me to even try unless it was something simple. Toss it up as a stupid mistake.
I think that is the best decision, I've wasted a lot of time trying to recover LiPo's over the years and only ever had one success on a 2S using a non-balance charger and that battery was probably only just under the limit, the others no hope.

PS. That 2S only lasted a shout time after the recovery and then puffed.
 

D.O.G.

Well-Known Member
Goblin 380 Supporter
I agree with you Fran. It's not worth taking the chance. Lipo fires aren't fun. No fire is fun.
 

Smoggie

Well-Known Member
If the battery was not fully discharged for long i've had good luck bringing them back from the dead. If they had been deeply discharged for a long period then usually there is no way back.
If you do it in a safe way there really is no increased risk. Just make sure you do the recovery in a safe place so that if the worst did happen and a cell 'popped' nothing bad would happen. When the batteries are at a low state of charge they are pretty much inert anyway. Personally what I've done in the past is to set the charger to NiCd/NiMh mode and charge at a very low rate monitoring closely all the time. The cells should quite quickly start to climb in voltage. Monitor continuously, if any cell doesn't start coming up then the battery is dead, dispose of it. If however the cells all start coming up quite evenly you are probably ok. Let the cells come up to about 3.5V (per cell) then stop the charge and switch over to LiPo mode. Now bring the pack up to storage charge and balance (if your charger has that capability).

Best now to leave it a day or two in a safe place. If it's still looking ok and all the cells remain balanced after a few days give it a couple of charge /discharge cycles on the charger just for good measure and if still fine I'd be happy to fly it. Keep a close eye on it for at least the next few uses to make sure all the cells charge normally and remain reasonably balanced after use. If you have an IR meter that's also a good test of cell damage.
 

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