battery drain

Discussion in 'Touring Models' started by Dirty, Sep 5, 2009.

  1. Dirty

    Dirty New Member

    My '93 decker (which is what we Canadians call a bagger or dresser) is draining the battery, just put a new one in drained it in 20 minutes. don't know if it's the volt pack going bad, stator or a live short. I'm suspecting a live short, but can't test for it. Anyone want to take a stab at helping with a fix? Any ideas? The bike is an FLHTC
    Thank you kindly....Dirty
    ( dirty is a state of mind as opposed to a state of being)

    NEWHD74FAN Experienced Member Retired Moderators

    Welcome Dirty to HDTalking, you will find a lot of fellow riders who will help and comment on diagnostics and making your ride more enjoyable. There are the tabs near the top of the page for self help tips as well as a search field to type in keywords to find related threads.

    Funny you asked this question when I just picked up a Clymer manual that has some of the Electrical diagnostics for the Bateery Current Draw Test...

    1) Current draw that exceeds 3.5 mA if equipped w/ TSSM (Turn Signal & Security Module) or 1mA w/ TSM (1000ths of an Amp) will drain the battery with the bike stored. The Regulator draws 0.5mA, the TSM draws 0.5mA, and TSSM draws 2.5mA.

    2) Make sure your battery is fully charged...and use a Digital Multimeter set initially to the highest AMP scale 1st (if you have a short you will likely blow the internal fuse in your meter). Pull the main 30A or 40A main fuse, then disconnect the negative terminal and put the meter (observe polarity of the test leads, though reverse will just show - polarity), - terminal to gnd stud, + terminal to Negative battery terminal. Install main 30A/40A main fues, read DMM and scale down if it is reading less than 10A, hopefully you will be able to scale below 1A.

    3) Now the tough part, "Divide and Conquer" because the leakage path can fan out from a single source, you will need a service manual to identify the connectors you decide to disconnect until you have isolated the leakage path. As you do so, inspect each connector and you may want to get a little history of any previous work done to the bike to get an idea of where to start. For example, you may have installed an accessory that is "On all the time" such as a GPS, Cell Phone or MP3 device you may have left on and pluged in, or running lights...! Good luck and keep us informed as to your progress.
  3. glider

    glider Veteran Member

  4. dangerdan

    dangerdan Junior Member

    Get yourself an amp meter with a range from 10 milli amps to 10 amps DC.
    Place it in series between the battery and the red cable, making sure your on the highest scale and observe polairity. Reduce the range on the meter till you get mid to full scale deflection. If you are using a digital digital display note the value. Now start disconnection wires. When you get a ZERO value you have found which leg or device is causing your problem.