A battery assembly with a housing that contains a removable battery pack. The housing, which is sterilizable, has a head designed to couple to a power consuming device. The battery pack, which is not sterilizable, contains at least one rechargeable cell. The battery pack has a head dimensioned to fit the same charger socket that can receive a sterilizable battery. The battery pack has contacts that abut charger contacts. The housing has internal contacts. Collectively, the housing and battery pack are shaped so that, when the battery pack seats in the housing, the battery pack contacts abut the housing internal contacts. The housing internal contacts are connected to the housing external contacts for supply power to the power consuming device. A cover selectively holds the battery pack in the housing chamber.