This is a circuit I used for an rc airboat powered by a 25cc weed eater motor with a 16" triple blade propeller. If my receiver system battery would get to low the circuit would activate the kill switch preventing loss of control. I powered the circuit through my receiver so if the receiver ever cut out due to low power my 5 foot long 40lbs airboat wouldn't go rouge and attack some poor kid at the lake. If the 7.4V power supply drops below 4.78 the relay switch activates. The circuit can be reset with the push button switch.
