Abstract: A battery adapter cartridge for removably positioning in a battery compartment of an electrically-powered device to provide electrical power may comprise an elongated case having opposite ends and defining at least one bay configured to receive a battery. The case may include a perimeter wall defining a case interior and each bay occupies a section of the case interior, with an opening formed in the case for each bay. The case may include a pair of end walls each positioned at a respective end of the cartridge and a pair of electrical contacts mounted on the opposite ends walls. The cartridge may include at least one electrical connector configured to connect to a battery positioned in the at least one bay and the electrical connectors and the electrical contacts are connected.