Originally Posted by
SQC049
Since this happened to two brand new batteries, I'd say it was user error.
Either he didn't have the lipo cut-off turned on, or he was charging on the wrong settings. This seems more likely to me.
It is quite common for Lipo's to poof up, this seems to happen when they are pushed extremely hard, however too much puffing can decrease the lifespan of your Lipo, this is why LiFe batteries are far better.
I'd get the largest spur and a 17t pinion.