Patent ID: 7855010

Claim:
A battery pack for a medical device having two operational states, wherein one operational state requires more power than the other operational state, comprising: a first battery having a voltage and a second battery having a voltage, the first and second batteries being in an enclosure, the enclosure being removable from the medical device, wherein the first battery has a capacity sufficient to power the medical device in the higher power operational state, and wherein the first and second batteries are electrically connected in parallel; circuitry in the enclosure and connected to the first and second batteries; a connector integrated into the circuitry to connect the circuitry in the enclosure to circuitry in the medical device; a microprocessor integrated into the circuitry in the enclosure and having programming and associated memory, the programming configured to perform self-tests on the circuitry in the enclosure and storing the results of the self-tests in memory; an OR gate electrically connected between the first and second batteries and oriented to permit the first or second battery having the greatest voltage applied to the OR gate to power the circuitry in the enclosure; a switch positioned in the circuitry in the enclosure between the first battery and the OR gate, the switch having opened and closed positions; whereby the first battery can only potentially power the circuitry in the enclosure when the switch is in the closed position.