ORIGINAL: xism
yes the batteries can be way to hot... iknow :P in my old jet stream the batteries was melting down after every run
i had twin 37 000 rpm k-speed motors and a 3-blade octura metal prop.
how to cool the batteries?
If your batteries are overheating your motor should be also. Try a smaller prop. A 2 blade prop will give more top end speed and less resistance and less heat to the motor and batteries. A three blade prop has more take off speed but less top end due to the resistance of a prop being in the water all the time and this resistance can cause heat build up on the motor and batteries especially on take off.