Why are my batteries getting hot?

[wevie]

I know better batteries make a difference. I let him run my LiPo's when I'm bashing with him, but for an inexpensive battery, I can buy him a box full of the Tenergy packs, let him run them and charge them, and never worry about a LiPo fault or loss of an expensive battery.

I'll pull the pinion and make sure the motor spins freely.

All wiring and connections have been double checked - we use deans exclusively.

What would the effect be of a steering servo going south? He only has a 2055 Traxxas servo. If it starts to go and draws excessive current from the system, would battery voltage drop substantially enough to overheat?