A cordless power supply comprising a battery, a power conversion unit, a first standard coupling half permanently affixed to the power conversion unit and a second standard coupling half which reciprocally mates with the first standard coupling half is disclosed and claimed. The second standard coupling half includes a first interengaging half and a second interengaging half. The first interengaging half being standardly engageable with the first standard coupling half permanently affixed to the power conversion unit. The second interengaging half is interengageable with a specific battery. The battery may be a dual use cordless tool battery or an original equipment battery. Alternatively, a cordless power supply comprising an interchangeable adapter may be mounted on the power conversion unit for interconnection with a plurality of batteries. Alternatively, a cordless power supply comprising an adapter integral with the power conversion unit may be used with a specific battery type.