This happened to me. In my case, I attempted to turn off my battery after a flight. Unknowingly, I didn't. The phantom was loaded back into the case and not checked on for several hours. I retrieved the case from my trunk hours later to find an extremely hot case, phantom and battery. I believe it would've caught fire had I not checked on it. Anyway, checking the history on the battery it showed that the battery got too hot and a damaged cell. You might want to check the history on that battery to see what happened. My case was totally my fault. You, however may have a bad battery. I use that battery only for per flight, on the ground checks. It's handy for that and that's all. Good luck with your situation.