Lipo battery swelling

[Rcrcrus]

Hi all. I'm needing a bit of advice on 4 of my lipo's that started swelling this weekend while racing.
I give you a bit of history. I have just moved to South Africa after living and racing in the Uk for a few years. I am running a Losi truggy with CC mamba combo 2200 kv and Losi buggy with a tekin combo. All my lipos are 4s, over 30c and over 5000mah and have had no problem in the UK.
Under standing it is a lot hotter here on race days. Two weeks ago i ran the buggy no problem. But this weekend i ran the truggy and 4 of my packs swelled up (well feels like just the wrapping swelled up) When they had cooled down because they were rather warm, not to warm to hold. It just feels like lipo has swollen and gone back down and left the cooled heatsrink behind. When i got home i checked them on a balancer and each cell was only 0.01-0.02v out, I thought that was still quit good. I then charged them with no probs at all and checked on the balancer again and all came out good 4.19v-4.20v per cell on all 4 packs. I have read that swollen packs should not be used but mine are not any more they have gone down and left the wrapping behind. Can any one tell me if my lipos are still safe or what. Please ask if i have left any details out.
Cheers

[Demon]

Sometimes lipo's will temporarily swell if you draw too much from them or if you exceed the discharge rate. It sounds like the higher temps you are facing has caused your cells to just about exceed their comfort zones.

Now that the lipo's have tightened up again they should be safe to use but make absolute sure you do not do it to them again. if you reach a point where they do not tighten up or that they are swelling up after every run - Then you want to dispose of them safely.

What i would try and do is set the low voltage cut-off on the esc slightly higher and limit the current the esc can draw from the batteries by reducing the punch / acceleration settings.

Hope that helps,
Demon

[jasonwipf]

I run in hot weather and that should not make them swell per say. run them to lipo cut off and then charge them up fully and see if you still really have 5k mah capacity. If you puff them a bit I'm suspicious you will not have full 5k mah capacity anymore. If they continue to swell at the end of runs and are running below 20-30% of their manufactured mah capacity, then dump them.