Patent ID: 7589497

Claim:
An information handling system configured to be powered by a battery or an alternating current to direct current (AC/DC) converter, comprising: an alternating current to direct current (AC/DC) converter; a load coupled to the AC/DC converter, the load representing powered circuitry for an information handling system; a charger coupled to the AC/DC converter; a primary battery coupled to the charger and to the load, the primary battery having an internal battery management unit (BMU) configured to be coupled to an external system management bus and an expansion battery interface, the expansion battery interface including a positive terminal, a negative terminal and a BMU control connection, the BMU control connection being separate from the external system management bus; and an expansion battery having an expansion battery interface, the expansion battery interface including a positive terminal, a negative terminal and a BMU control connection, the expansion battery interface being coupled to the expansion battery interface of the primary battery; wherein the BMU within the primary battery sends control signals to the expansion battery through the BMU control connections and the primary battery and the expansion battery together provide battery power to the load.