6 volt battery drain problem

[Capt. Chris]

I have developed a constant battery drain problem on a stock 6 volt positive ground system. I have checked across the solenoid with a meter, seems good. Disconnected power lead to instrument panel, no effect. I am thinking voltage regulator is incorrect for car. Prior owner replaced it, it is new, but blue in color. I looked in a couple of T-bird catalogs, and it appears the blue cover designates 12 volt unit. Don't know how to check this. I vaguely remember that voltage regulators can cause battery drain, but can't remember how to test. Yes, I am older than the car! Any suggestions?

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[doug7740]

Chris,

My 1955 Thunderbird has a 6 volt positive ground system and the voltage regulator cover is black. I agree with you that you may have the wrong regulator for the car, but maybe the prior owner replaced the regulator because of the battery drain issue.

What were your readings when you checked across the solenoid with a meter?

This is how I check for a battery drain:

1. Turn off everything that uses electricity
   
2. Remove the battery cable that goes to the starter solenoid from the battery
   
   
3. Connect a multimeter set to measure DC volts between the battery terminal and the cable. If it reads battery voltage, there is a drain.
   
   
4. Switch your meter to read DC amps (start at the height range to prevent damage to the meter) and measure the current flow. If the reading is 1 amp or more, then quite likely there is something still turned on. Any current flow between 1 amp and .01 amps is a major electrical drain. Less than .01 amps is a minor drain.
   
   
5. If a drain is detected, first clean the battery terminals, battery top, and the battery cables, than one at a time remove fuses and disconnect wires until the current drops to zero. When it does you have found the source of your battery drain.

A voltage regulator will cause the battery to drain if the cut-out relay contacts are stuck closed. The voltage regulator testing procedure is listed starting on page 112 of the 1955 Ford Car Shop Manual.

Doug
1955 Thunderbird Blue

 

[biddle]

You can get the reprint of the 1955 Ford Thunderbird Car Shop Manual here on book or here on CD-Rom