Patent ID: 8820286

Claim:
An electrical power supply system, comprising an engine-driven generator configured to output only electrical power as needed, an alternator/starter operatively connected with the engine of the engine-driven generator, a rechargeable power storage device associated with the alternator/starter so as to constitute the only power source for an engine starting function and the only power storage device between the alternator/starter and an electrical load, and a control device operatively arranged between the alternator/starter and the power storage device for switching the alternator/starter between an alternator function and the engine-starting function such that the power storage device is the sole output power source to the electrical load up to a first power demand of the electrical load without starting the engine and thereafter at a second power demand of the electrical load higher than the first power demand the power storage device supplies power to the alternator/starter for the engine starting function whereupon the engine then starts to recharge the power storage device and through the power storage device to provide power to the electrical load.