Lipo slightly swollen

[JDinkelman]

Yesterday, after a bit of bashing in hot weather, I noticed my soft case lipo (Turnigy Nanotech 2S 3300mAh was a bit swollen. It was discharged to approx. 3,7V per cell at that stage.

I gave it a rest and discharged it to 3.0 per cell and charged it up to storage voltage of 3.7V later. Now it does not feel as swollen as yesterday but it is a bit "looser in it's jacket" than it originally was. It just seems that the outer wrapping has been stretched a bit. The white inner jacket did turn a bit yellowish compared to a new pack of the same type.

It's not quite a new pack so if there is significant risk in keeping it in use, I will discard it but I do not want to dispose it unnecessarily.

Before disposing it (to the appropriate channel), I guess I should discharge it completely (i could solder a car bulb to the leads).

Any input is welcome.

[taffer]

isnt the method just to soak it in a bucket of salty water? you'd have to google it

[Backlash]

If you do a Google search for "lipo battery swelling cause", you can find quite a bit of information on the topic...

http://barnson.org/node/1842

[JDinkelman]

Reading around, it seems the salt water trick is not without controversy.

I decided to gently discharge it to 1V using my charger (outside and monitoring the temp).

After that I drained the last bit with a brushed motor and tied the wires together.

I guess it should be safe to bring to our local disposal site now.

[Juls1]

Slight swelling seems to be relatively normal, main causes are overdischarging, or storing fully charged. 

A little swelling isn’t unusual I’d keep using it just keep a closer eye when charging and store it in your charging sack. 

[wolfdogstinkus]

One of my cheap floureon lipos is showing a large imbalance, 2.8v to 3.2. No sign of puffing. Going to check voltage cut off is set correctly.

[ncpantherfan71]

6 hours ago, wolfdogstinkus said:

One of my cheap floureon lipos is showing a large imbalance, 2.8v to 3.2. No sign of puffing. Going to check voltage cut off is set correctly.

That is usually caused by one cell having a much higher internal resistance.   Basically what happens is the cell with higher or takes longer to discharge and the better cell discharges too low. 

No fix for it,  if it is an old pack time to trash it,  it will only get worse over time.   If it's a new pack you can try to cycle it a couple times,  but most of the time it ends up being a bad pack.