Abstract: An intelligent switch for preventing over discharge of a vehicle battery includes a switch connected to toggle between a first state for preventing current flow from the battery and a second state for allowing current flow from the battery. A voltage monitor provides a voltage signal indicative of the voltage level of the battery. A vibration sensor provides a vibration signal indicative of vehicle vibration. A controller is connected to receive the voltage signal and the vibration signal and generate a control signal for toggling the switch to the first state when no vibration of the vehicle is detected and the voltage level of the battery falls below a predetermined voltage threshold. The controller generates another control signal when vibration is detected to toggle the switch to the second state. Multiple voltage thresholds and associated timers are used to maintain an adequate battery charge level under variable load conditions.