a battery adapter provides a housing having an outer shape corresponding to a pair of juxtaposed standard cylindrical type battery cells . a pair of electrical contacts are supported upon the housing to provide electrical connection to environments which would normally receive a pair of standard cylindrical type cells or combinations thereof . a long life battery having a voltage approximately double that of a standard one and a half volt battery is supported within the housing and electrical connections are provided between the terminals of the internal battery and the external terminals supported on the housing . embodiments are shown in which the internal battery may be replaced . embodiments which replicate either parallelly arranged or serially arranged cell combinations are shown .