Patent ID: 8049364

Claim:
A backup power system for providing substantially uninterruptible backup power to an appliance during a main power failure comprising: a first electrical connector and a second electrical connector; a relay that electrically couples the first electrical connector to the second electrical connector when electrical power is applied to the first connector; a charging circuit electrically coupled to the first electrical connector; a rechargeable battery electrically coupled to the charging circuit; a current converter; a voltage circuit configured to provide a full voltage to the second electrical connector until the voltage level of the battery reaches a predetermined level, wherein the voltage circuit is configured to provide less than full voltage to the second electrical connector; and a switch-timing circuit operatively coupled to the current converter such that the switch-timing circuit is positionable to override the voltage circuit and provide full voltage output regardless of the voltage level of the battery; wherein the relay electrically decouples the first electrical connector from the second electrical connector and electrically couples the current converter to the second electrical connector and to the battery when electrical power is removed from the first electrical connector.