An electric adapter for providing output power to an accessory includes an adapter housing having a projection configured for insertion into a DC power accessory port, the projection carrying an electrical input conductor, a power outlet cord extending from the housing, a manually operable power switch mounted on the housing, the switch operable to electrically connect the electrical input conductor to the power outlet cord, and a timer circuit contained within the housing and configured to electrically disconnect the input conductor from the power outlet cord after a predetermined cycle time period, without removing the projection from the DC power accessory port.