VCCA Home Forums TECHNICAL - GENERAL Electrical - 6 volt 38 complete battery drain overnight

I do not see anything that is on and all has been well for years no problems. Generator rebuild 500 miles ago. Any ideas why the battery would be stone dead overnight? I tried 3 different batteries just to be sure. Thanks

Generator or alternator? If you're running an alternator a diode can go bad causing it to pull power when off. The only way I know of to solve a parasitic load is to put a meter between the negative cable and the battery to show the draw, then start disconnecting things one at a time until the drain stops. On a more modern car it would mean pulling fuses one at a time to isolate which circuit. Before you start down that road put a full charge on your battery and have it load tested.

Circuit breaker in voltage contol or voltage regulator not opening up.

I agree with checking both sets of points in the voltage regulator.

I know this sounds crazy but do you have an accessory clock on the glove box door? If the clock mechanism gets dirty the motor can start drawing more current and can drain a battery. However that typically takes a few days.

If it is not the voltage regulator you will need to troubleshoot individual circuits. Connect an ammeter between the battery and starter. Remember that an ammeter needs to be connected in series in a circuit to read properly. Disconnect the battery cable from the starter terminal and connect the ammeter between the end of the cable and the terminal on the starter.

There should be no current reading if everything is turned off. If there is a reading then systematically disconnect things until the reading goes to zero. That identities the problem circuit. Then you need to figure out what is wrong in that circuit.

Blower motor but it was stuck and you could not hear it... Thanks guys,

Don't those problems drive you crazy. How did you find it? Wire that was hot to touch?

Glad you found the source. Finding simple electrical issues can be a challenge.

I have a master disconnect on my car that is use when I know it will be more than a couple of days before I drive the car again.

I'm surprised it didn't let the smoke out.

i recalled putting a rag in the blower in the off season do when you hit bumps it did not rattle. id pull it out in the fall. I forgot is was in there and accidently turned the switch on. I recalled the rag pulled it out and that was it..

So did the motor survive that heat?

yes.. still working