Voltage Regulator Question

pebo va

Member
In my stock '49 6 volt flathead, is it possible that a malfunctioning VR could drain the battery over 5-7 days in the garage with all electrical components turned off?
 
Yep, I had the same problem with my '51 a few years ago; let it sit too long (in my case, 2 or 3 days) and the battery went dead. I changed out the VR for a know good one and it solved the problem.
 
Generally no, but if the cut out contacts were stuck closed then current could flow to the generator and cook the armature. You would see smoke coming out of the generator and it would be very hot to touch. Most likely something else is draining the battery or the battery itself is faulty and draining internally. You should have a battery cut off switch fitted to any car that sits around a bit to ensure it is safe. Need to do some testing here to find where the problem lies. Connect an ammeter or voltmeter in series with one battery cable and see if you get a reading with everything turned off. Should be zero really on a car like yours providing there are no add on electronic modern items fitted. Regards, Kevin.
 
If you take the battery lead on and off you might see a small spark if something is draining current.
 
Brake light switch sticking or a bad ignition switch can cause parasitic battery drain. Using an amp meter between an isolated battery terminal and a battery post will tell if you have a drain. Disconnect generator wire or other "hot all the time" loads one at a time will usually confirm what is causing it.

If the cut out pole in the voltage regulator is stuck closed, it tries to motor the generator but it will kill the battery power or generator a lot quicker than a person might think.
 
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