Concorde Battery Corporation offers a Parasitic Load Tester (PLT) to measure the parasitic load / drain on aircraft batteries when the master switch is off and the aircraft is inactive. The tester is designed to mate with a MS3509 style quick disconnect receptacle. This innovative PLT was conceived and engineered in response to concerns in the aviation community about the effect of parasitic loads / drains on battery capacity, state of charge, airworthiness and battery life.
Measuring parasitic load is easy to do by connecting the PLT between the battery receptacle and the aircraft mating plug. The PLT is a molded polypropylene body equipped with separate test leads for connection to a digital multimeter (DMM). Concorde PLT part number 4102, is rated for loads up to 10 amperes and is equipped with a 10 amp fuse.
Instructions on how to measure parasitic load and calculate time to battery depletion are provided in Instruction Manual, Aircraft Battery Parasitic Load Tester, Document No. 5-0409. The manual is packaged with the PLT and is also available online at www.concordebattery.com.