I'm kind of bouncing around between two threads on this subject. I think in my case it was operator error in that I allowed juice to leak into the battery through improper refilling technique.
My fault, not gonna whine about it. Good thing I bought three batteries. If the battery craps out on me I'll be perfectly happy to tear it apart just for fun. It's all good in the end. So folks, always remove your carto when refilling.

