The AX2550 includes a battery voltage monitoring circuit that will cause the output transistors to be turned off if the main battery voltage applied on the thick red and black wires is above 45V. This protection is designed to prevent the voltage created by the motors during regeneration to be “amplified” to unsafe levels by the switching circuit. This circuit will not protect the controller against powering the controller with a power source above 45V. The controller will resume normal operation when the measured voltage drops below 45V