wheelies?

[BrianG]

Ah, maybe drivetrain drag causing the motor to work harder.

You said that you'd think that 12 cells would run cooler than 14 cells. Well, I thought the same thing, but when I first put Revo V1 together (feels like ages ago), I used both 12 and 14 cells and found that the motor was hotter and runtime was worse on 12 cells. Some of the helpful people here mentioned that it might be because I was on the throttle harder with 12 cells to make up for the difference in power from the lack of the 2 extra cells. Maybe that's what is happening to you?