I have an 85 fxrt that has a problem with battery draining down when parked for a couple of days. It's new, an agm from nappa. Thought the first one was bad, returned it for a new one same thing happened. What's the likelyhood of 2 bad ones. I've owned this thing for 19 yrs this is the first year of trouble. Very simple electrical system I'm looking for any suggestions in order to save some time. In this system what can remain energized when the key is out and engine off
thanks folks

 

Are you turning the key to ACC before removing?? That would drain it. If not there could be a short in your regulator.

 

If you don't have one get a battery tender, which will keep your battery in good condition while 'we' sort things out! Also if you have a multi-meter do some basic checks of leak down. These are the sorts of problem where two heads are better than one, so if you have a buddy who can lend a hand that would be helpful. We'll do what we can, but with me peering through the gloom over the Atlantic and Spanners doing the same across the Pacific we're a bit limited in what we can do!

 

Do you have a radio?

Put an ammeter in line with the battery to ground with the bike off. Measure the current draw. Tell us. The next step is to start disconnecting major circuits until the current draw drops off, then look in that circuit. Problem areas: Radio/accessories, voltage regulator.

 

You definetly need to use a multi-meter to sort things out. As stated above, disconnect the ground cable and hook the multi-meter betweem the terminal and the cable and see how much of a draw you have. If a draw is present start unhooking things until you find the problem. I would start with the regulator, then go to anny accessories that were added next, then finally the rest of the harness.
But before you do the above hook the multi-meter up to the battery and see what the voltage is. Then start the bike watching the meter, the voltage will drop when you crank the engine over, note the reading. After it is runnung the voltage should go up, rev the engine to about 2,000 RPM's and note that reading. Then post those reading and we can go from there. Hope this helps.








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+1 here. Putting an ammeter inline with the battery with the ignition off will show you if something is drawing current and therefore draining your battery.

 

Come on man, get to it! We need results, results and data!!!! :-)

 

Hey spanners, which side of the date line are you on, is it today or tomorrow where you are ????? LOL

 

Gonna watch this one....

I have the same issue on my '86 FLH

Had the local dealer look at it, everything checks out.

I just hook it up to a battery tender every night. I suspect 25 yr old wiring is creating an intermittent issue.

 

Usually tomorrow mate :-) Whatever day it is...we see it first :-)....I am your future....