Patent ID: 7550874
Filing Date: 2009-06-23
Classification: H01M,H02J,Y02E

Abstract:
1. A power supply apparatus comprising: a power output; a first power source selectively connectable to the power output; a second power source selectively connectable to the power output; a switch connected to one of the first power source and the second power source, said switch being configured to couple the first power source with the power output until the first power source becomes substantially depleted, said switch further being configured to couple the second power source with the power output after the first power source becomes substantially depleted; a controller configured to identify substantial depletion of the first power source, and to precisely estimate the amount of power remaining in the power supply apparatus immediately after the identified substantial depletion of the first battery based on the full storage capacity of the second power source; and an indicator connected to the controller, said indicator being configured to convey the amount of power remaining in the power supply apparatus immediately after the identified substantial depletion of the first battery based on input from the controller.