Abstract: In one embodiment, a system for monitoring and indicating remote battery charging comprises a sensor unit, a power source, at least one remote battery, and a wiring harness; wherein the sensor unit comprises an analog to digital converter (an “A/D Converter”) and a display means such as lights (e.g., LEDs) and/or a screen (e.g., LCD). In one method of use, the system for monitoring then monitors the power supply (the source) as well as the auxiliary charging system (e.g., the liftgate electrical system) and provides advanced warnings or signals when the system is not receiving sufficient power or is otherwise not functioning properly.

Abstract: A vehicle incorporates a crank battery, a rechargeable auxiliary battery, and an onboard electrical power source separate from the crank battery and the auxiliary battery. A battery charge controller manages a supply of electrical energy to the auxiliary battery to charge the auxiliary battery. The battery charge controller includes a first comparator for monitoring a voltage level of the crank battery, and a second comparator for monitoring a voltage level of the onboard electrical power source. A first switching device electrically couples the crank battery and the auxiliary battery to charge the auxiliary battery when the voltage level of the crank battery exceeds a first voltage threshold, and electrically decouples the crank battery and the auxiliary battery when the voltage level of the crank battery is below the first voltage threshold.