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Overnight battery drain

Posted: Fri Jul 13, 2018 9:21 am
by Stan
OK you Bronco electrical gurus ; can a bad voltage regulator or a bad alternator drain a battery overnight ?
I know a bad starter{ short } can do that among other things.
I was having some charging inconsistancies previous to the drain down so I was doing a little trouble shooting and know the battery was full charge the previous evening.

Re: Overnight battery drain

Posted: Sun Jul 15, 2018 4:26 pm
Hey Stan... Yes and Yes, so can other stuff... but its easy to diagnose properly if you have the right tools. Is your battery good? !.. an Amp meter placed in series between the negative battery terminal and clamp will tell you if your ignition off draw is out of spec, and tell you once you have found the problem.

A general rule of thumb is 30 milliamp draw... these older rigs, even with an aftermarket radio may be as high as 10 milliamps. If its above 30... start pulling fuses, if it still does not drop... start disconnecting; alternators, headlamp switches, stop lamp switch, distributor/ignition module... If it is not intermittent, its easy.

Hmmm.. What about your electric cart chair lift?

Re: Overnight battery drain

Posted: Mon Jul 16, 2018 8:35 am
by Stan
Thanks for the tips Shawn .
I replaced the VR and the Alt and haven't had an issue again/yet.
LOL I went to propane with dual mixers tp power the generator for my " chair lift "

Re: Overnight battery drain

Posted: Sun Jul 29, 2018 12:09 am
by DirtDonk
Glad you got it fixed.
The quicker the drain, the more likely it is to be the alternator. If you have for testing the next time, you can try disconnecting the plug from the regulator overnight to see if the battery still drains. If not, bingo. But if it does, plug it back in and disconnect the charge wire from the alternator.
You can do this either directly on the back of the alt, or easier on most EB's would be to find the 3-wire black plug with the wires from the alternator and disconnect that instead.
If it stops the drain, you've found your issue.

If it still drains, and you can't find anything else obvious, it's probably your battery dying an early death.
Glad yours was an easy find.


Re: Overnight battery drain

Posted: Sun Jul 29, 2018 3:16 pm
He should give me his sweet ride... its just going to plague him again and he doesn't need the aggravation :D

Re: Overnight battery drain

Posted: Wed Dec 19, 2018 12:00 am
by brncofan
I experienced the same problem and the voltage regulator was the culprit.