I have used two of these batteries. I bought the Piper J-5 cub and used the battery that came with the plane. After a while, I would say maybe 10 or 15 flights, the battery started to puff up. So I ordered a new one. The second battery did the exact same thing as the first one.

The battery seemed to give pretty good power at first and I would get 8 to 10 minutes of flying. I fly pretty slow and don't do a lot of tricks. When the battery first started to puff up, the flight times were a MAX of 8 minutes. Now, after maybe 20 flights, I get maybe 6 minutes.

After my last flight, the battery is so puffed up, I really think it could burst if I try using it again. I'm going to try to carefully discharge it and dispose of it.

I have since used two other batteries with this plane. Both of the others are 3 cell batteries. I haven't had problems with either of those.