Abstract: A battery drain limitation circuit, for use in engine-powered vehicles and equipment that rely on a battery for starting the engine and for operating accessories, disconnects the battery from all loads when the battery voltage falls to a level below which the battery charge may be insufficient to start the engine. The circuit is rendered inoperable, when the engine is running, by means of a microphone that detects engine noise. The circuit includes a reset mechanism that reconnects the battery to all loads. The reset mechanism may be automatic or manually actuated. A timing circuit delays the disconnection for a period of time sufficient to start the engine. The drain limitation circuit employs a latching relay that, in its preferred embodiment, includes front and rear coils in tandem, axially separated by a collar with an internal detent. A front plunger and a rear plunger are disposed for axial movement within the coils and the collar.