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AIRFRAME TECHNOLOGY made to reduce or eliminate the par- asitic drain. The aircraft manufac- turer should be contacted for more information on this subject. Another option is to disconnect the battery plug from the battery, which stops a p allll parasitic loads. This procedure is ofte often referenced as part of the air- cra oper a Ho the cr raft maintenance manual or pilot's ope ating handbook. However, if not specifically referenced, the aiircraft manufacturer should be con contacted to verify acceptability of thi this practice. How to measure the parasitic load The parasitic drain of an air- craft battery can be directly mea- sure sur d with a digital multimeter (D ter unction. Most DMM's have separate jacks for low current (typ (DMM) equipped with an amme- ter f (typically 200 mA maximum) and h hiigh current (typically 10A maxi- mu mum) measurements. The amme- ter jacks contain a fuse to prevent Parasitic loads can deplete the battery's capacity if the aircraft is inactive for an extended time and . . . render the aircraft inoperable. damaging the internal electronics. It's always best to start measure- ments using the high current jack, and then switch to the low current jack if the measured current does not exceed the low current jack's rating. The low current jack will give a more accurate measure- ment of typical parasitic currents (generally 1-100 mA). Concorde has recently devel- oped a Parasitic Load Test Adapter (PLTA) that makes it very easy to measure the parasitic load www.AMTSociety.org • www.AMTonline.com • Aircraft Maintenance Technology September 2011 21 of aircraft batteries equipped with an MS3509 style quick disconnect receptacle. The PLTA is designed to connect between the battery receptacle and the aircraft's mat- ing plug, with separate test leads for connection to the DMM. The PLTA is rated for loads up to 10 amperes. Step-by-step instruc- tions for the PLTA can be found in document number 5-0409 available on Concorde's web site (www.concordebattery.com). Protecting the battery from parasitic loads To protect the battery from being depleted by the parasitic