Patent ID: 7148637

Claim:
A portable compound battery unit management system for an electrically powered vehicle, comprising: a DC converter coupled to a motor controller, said motor controller being coupled to a propulsion motor of the vehicle; a main power battery unit coupled to said DC converter for supplying power to drive said propulsion motor, said main power battery unit including a plurality of cells coupled in series and a battery management means for limiting a maximum output current of said series coupled cells, said battery management means being coupled to said DC converter and said motor controller to provide battery operational data thereto; and at least one interchangeable and portable high power density supplemental battery unit detachably coupled to the vehicle and having a built-in battery management means having a low capacity cut-off and being connected to said DC converter, said supplemental battery unit being selectively removed for charging independently of said main power battery unit with an external charger, said supplemental battery unit powering said propulsion motor in parallel with said main power battery unit through said DC converter for sharing the power demand thereof; said DC converter converting an output voltage of said supplemental battery unit to match an output voltage of said main power battery unit and selectively coupling said supplemental battery unit to said main power battery unit.