Battery drain

[Reelnative]

Can someone help steer me in the right direction, the othe morning my 1930 Tudor, 6 Volt, Positive ground with Alternator had a dead battery. I charged the battery and it came back fine, its just over 1 year old, I didnt start it then but a few days later it was dead again. I disconnected the positive to the frame and charged it again, I thought suspect there id a draw so I connected my volt meter from the battery to the frame and with the key off it reads 1.3 volts, when I remove the fuse from the starter it goes to zero. I believe i have a bad ignition switch, any ideas on wht to check woud be appreciated.

Thanks

[BRENT in 10-uh-C]

Originally Posted by Reelnative

Can someone help steer me in the right direction, the othe morning my 1930 Tudor, 6 Volt, Positive ground with Alternator had a dead battery. I charged the battery and it came back fine, its just over 1 year old, I didnt start it then but a few days later it was dead again. I disconnected the positive to the frame and charged it again, I thought suspect there id a draw so I connected my volt meter from the battery to the frame and with the key off it reads 1.3 volts, when I remove the fuse from the starter it goes to zero. I believe i have a bad ignition switch, any ideas on wht to check woud be appreciated.

Thanks

In a nutshell, the self-exciting regulator in the Alternator is your parasitic draw. Find a way to disconnect the wire to the alternator when the vehicle is not being driven and you will likely cure your issue.

[alexiskai]

Previous thread with more info on parasitic draw:
https://www.fordbarn.com/forum/showthread.php?t=301566

[Y-Blockhead]

Originally Posted by BRENT in 10-uh-C

In a nutshell, the self-exciting regulator in the Alternator is your parasitic draw. Find a way to disconnect the wire to the alternator when the vehicle is not being driven and you will likely cure your issue.

To add, if you have a bad diode in the alternator rectifier, your battery will drain even faster.

[nkaminar]

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A few points:

1. Disconnect all the items, like you did with the fuse, and then test with an ammeter to see if that is the source of the drain. Look at the alternator, stop light, etc.
2. Install a battery disconnect switch. This is a safety item in case you have a bad short or electrical fire while on the road. It also can prevent theft and will stop all battery drain. Install it where accessible without having to take anything apart.
3. Batteries don't like to be totally discharged. A starting battery can be damaged if discharged beyond about 20%. After you fix your problem, have the battery load tested at an automotive store.