Patent ID: 8148855

Claim:
A method for supplying cordless power from a portable power supply system, the method comprising: at a first power supply unit, sensing whether a second power supply unit is coupled to the first power supply unit; if the second power supply unit is sensed to be coupled to the first power supply unit, then receiving electrical energy at a first energy storage device, via a first switch, from the second power supply unit; whereas if the second power supply unit is sensed to not be coupled to the first power supply unit, then receiving electrical energy at the first energy storage device, via the first switch, from an input source; and at the first power supply unit, sensing whether a third power supply unit is coupled to the first power supply unit; if the third power supply unit is sensed to be coupled to the first power supply unit, then directing electrical energy from the first energy storage device, via a second switch, to the third power supply unit; whereas if the third power supply unit is sensed to not be coupled to the first power supply unit, then directing electrical energy from the first energy storage device, via the second switch, to an output destination.