RC India

5 days back i have charged my lipo (2200 mah 3s ) fully and went to flying, flew only 2 minutes and due to strong wingdi came back.. after coming back .the lipos were good and showing 11.5 volts with all the 3 cells balance.  now after 5 days ( yesterday ) when i checked 1 cell was puffed . the lipo was completely drained  :o. the volts were 0, 1, 0.  ??? 
how it happened .
same thing happened to other battery 3s. one cell gone dead.
I tried charging at 0.1 volt, but low voltage lipo message is shown, and it is not charging.

Please help. how can i re-store it back again.

WHY is this happening. does this moist weather is playing a role in it ?

did you leave it on the aircraft ?

You have to charge this LiPo on your balance charger on NiMH mode to revive it back . I also faced similar problem when I forgot it in the aircraft connected.

Do you mean 0.1 volts or 0.1 Amps? I doubt charging the 11.1 v at a p.d of 0.1 v would be of any use. It would take a loooong time to even show a 0.05 v increase.

very important to disconnect the Lipo from the
esc/bec after flying. lucky no accident happened with the lipo connected to the ESC and the radio off.
you can trickle charge it on NICD mode at 50mA until the voltage of each cell comes upto 2.5 V took 20 min for me. then charge it as ussual. if you are not sure, don't try it. Lipos burn and explode.
regards
Avijit

Reviving a lipo depends on how badly is it puffed...it an be revived only if it's slightly puffed however if it's puffed badly then you may have to remove this cell and dispose it properly.

Hellyflyer

Yes sir i left it to the aircraft . but was disconnected from esc .


means what we call  as trickle chearging.



it was slightly puffed.

but why the same happened to my other lipo. 1 cell died out of three. it was safely placed.

i surely cannot do much to the 2200 lipo where all cells are dead. 
what can i do to the other lipo where 1 cell is dead. i donot want to remove and make it to two cells.

avijit you means 5.0 A ?

@swizera - LiPos do not need trickle charging, its  of no use to the LiPo. and would rather add to the damage if not reverse, and cause them to imbalance even more. They do not lose current as fast a NiCd's or NiMH and dont need a top up, and do not exhibit memory effect.

At the same time, Zapping the battery (Applying a short lived high current through the battery) is also a no because Li cells dont handle it well and can burst causing fire.

You will have to charge it at the right current instead using a constant current source (A NiMH charger). Since its a 2200 mAh, can try charging it at a 0.2-0.3 Amps for a short time (about an hour or so, but depends on the swell on the battery, will have to keep a watch, for any further swelling, heat up). And it might just work but if its badly swollen, its better to get a new one. Place the battery on a flat surface and if it rocks, it needs to go.

Hope that helps

Avijit means 0.05 Amps. It is dangerous to charge LiPos at more than 1C (although some newer batteries allow but a LiPo explosion injury is something everyone of us wants to stay miles away from)

Your battery is 2200mAh (MilliAmpHour) = 2.2 AmpHour
At 1 C rating you should be passing no more than 2.2 AmpHour  * 1 C = 2.2 Amps of current through it.

And do you have a mechanical switch in your circuit so you can turn off the switch when not in use.

thanks girish . i let go the 2200mh lipo.
but will try to recover the other lipo  8-)

But still i did not understand why this Happened  ??? ??? ??? ??? ??? ???

This happened cause you left the battery charged as you mentioned that you charged the battery but could not fly due to bad wheather. Batteries get puffed if you keep them on charged on shelf for longer than 2 days, so it's recommended to keep batteries at storage mode if you are planning to keep it for 5days or more.

I hope this helps.

Hellyflyer

All the best for the other ones. :thumbsup:

Thanks a lot to all for the help.
the lipo having one cell damage , i have put to nimh  charge with lot of fear for 15 min.
now it is showing some charge in  it . now charger is detecting 3 cells . now i have put it to normal lipo charge mode. hope to see good results.
2200 mah 1 cell i have discarded and will try do do same nimh charge with other two. if they work will make 2 cell baty. or ........