An improved circuit supplies electrical power to a vehicle accessory load, such
as a load that is powered through a vehicle accessory load connector or cigarette
lighter plug. The circuit utilizes battery voltage comparator and timer switching
circuitry to interrupt the supply of power to the accessory load if the engine-driven
alternator fails to charge the storage battery for at least a predefined time interval
(i.e., when the vehicle engine is not running), and to automatically re-establish
electrical power supply to the load when battery charging resumes (i.e., when engine
operation resumes).
