electrical problem

[Scott S.]

Hi all,

I am beginning to have a problem where it appears something is loading down the battery on my 1960. This seemed to come from nowhere. It completely discharged the battery I had after I had not run the car for a couple of weeks. I thought it might be the older battery I have had. I got a new battery and when I hooked it up the car is discharging about a quarter way to the left even after I had been driving for 45 minutes.

Typically the amp gauge is just left of the center line with the car running. The battery voltage with the car not running was about 12.7V last night and down to 12.2V this morning.

• With everything off what do you think would be the normal current being pulled from the battery(I assume about 0)?
• Besides pulling the fuses and looking at the current drain, is there any good method to isolate the problem.
• Any other tips would be greatly appreciated.

This is my first electrical problem with the car and I would love to avoid a shop visit cost although I admit the electricals are not my strong point.

Thanks,
Scott

[Richard M.]

Re: electrical problem

Scott,


Right, with everything off ammeter should be 0. With engine running at idle it can be slightly discharged, but after about 800+ rpm it should show positive on the meter. So.......

My first thought would be the clock. Disconnect it as the contacts can fuse shut. There is no fuse in the clock or cig lighter circuit so be cautious.

Second thought would be a bad voltage regulator, always keeping the field coils in the generator energized, thus draining the battery. A cold engine bay with a warm generator would be the clue.

With the engine running at 800+ rpm you should be at about 14.5 volts at the battery. If not your regulator is likely bad. Could be a generator but the regulator is the weak link on these old systems.

Rich

[Scott S.]

Re: electrical problem

Hi Richard,

Thanks for the reply. It was helpful. A couple of things.

When I asked about the current drain with the motor off, I meant if you disconnect the + battery cable, put an ammeter is between the + battery post and the positive cable, what kind of current would be normally pulled from the battery and what is considered high. That way if it is too high, you can start pulling fuses to see where the current drops off and have a hint about the load source. This is probably a hard question.

My car actually has an alternator (not an original motor). The idea of checking for a warm regulator is a great idea. I read some other archived posts and they gave some hints. My car does not have a working clock or lighter but I might want to check those connections anyway to see if some wire is shorting.

Thanks again for your help.
Scott

[William C.]

Re: electrical problem

on a '60 the drain on the battery with the ignition off and no clock should be ZERO. Drain did not become an issue until electronic clocks and radios came in with memories that had to be maintained, then computers with more memories, then who knows what?

[Tom L.]

Re: electrical problem

The way to determine whether or not you have a draw is to place your multimeter between the battery and a battery cable (+ or -, it makes no difference). Set your multimeter to milliamps. Make sure the key is off and no accessories are on, otherwise you'll smoke the fuse in your meter. With the meter in-line, any current draw will pass through the meter and give you a reading. Any more than 30-40 ma will drain your battery rather quickly.

If you have a newer style alternator with an internal regulator, as you mentioned, I suspect that's where you'll find your problem. When those regulators fail, they will draw current as if they didn't turn off with the key. Since there isn't much else that could potentially cause a draw on that car, I suspect that your ma draw will drop precipitously with the regulator unplugged (two wire plug on alternator). If so, that's the problem. Good luck.