Concorde Battery`s Parasitic Load Tester Adaptor (PLTA) used in conjunction with a digital multimeter (DMM) will measure the parasitic load on aircraft batteries when the master switch is off and the aircraft is inactive. The adaptor is designed to mate with a MS3509 style quick disconnect receptacle. The innovative PLTA was conceived and engineered in response to concerns in the aviation community about the effect of parasitic loads on battery capacity, state of charge, airworthiness and battery life.