VCCA Home Forums TECHNICAL - GENERAL Electrical - 6 volt '50 Deluxe - battery overcharge?

Hi guys -

Working on a '50 Deluxe I bought earlier this spring, and I think I'm running into a battery overcharge situation to fix.

Over this weekend, while working on other things on it, I noticed the battery was gently fizzing a bit, and turning the caps on it seemed to relieve it of this mild fizzing. I just happened to be listening to "Car Talk" this Saturday about a caller who had battery fumes, and the prognosis was a failing voltage regulator "cooking" the battery. I'm wondering if I have the same thing.

My first knee-jerk reaction would be to buy a new voltage regulator, but, I see in the Chevy shop manual that you can test, and then adjust, the voltage regulator. So, I'm wondering if I can do some initial testing and tweaking to see if I'm having the same issue. Right now the voltmeter shows 6.46V on the battery. Is this a fairly common issue to diagnose and correct on a 6-V system like this?

That would be the normal voltage for the battery. The question is what voltage the generator is set at. It would be about 7.4 volts. The battery will not go over a 6 V reading. Read the section on checking the reg.voltage.
Actually it is a guessing game trying to adjust a regulator without the proper equipment. I doubt if any of the proper equipment is around today.

Given if there isn't a proper way to adjust a voltage regulator, am I best served to just buy and install a new one; and then if everything is hunky-dorey, then hurray - otherwise keep tracing back to other problems?

Oh, if I can add further info to help the prognosis: the previous owner was smart enough to tag the current regulator with the date it was installed: 10.1.01. Is it reasonable, then, to suspect a 12-year-old replacement regulator could be reaching the end of its useful life?

If it is a 12 year old Delco regulator the "book" adjustmments will not be correct due to changes. Are the cover screws long and go through from the top of the cover or short and just at the edge of the flange?
I have a 12 year old regulator on my '50 which replaces the 50 year old original. The date of manufactor is stamped on the base.
Does the ammeter show a strong charge at all times? It should drop back to the center after an hour or less of driving.

Thanks, ChevGene. It's neither - it's some off-brand replacement regulator.

Ammeter shows the usual up and down on Discharge---Charge range depending on idling, lights on or off, that kind of thing.

Battery over filled?

If you have a quality regulator it should last a lot longer than 12 years.

Hi ya JYD !

No, that can be a item to hone in - I couldn't say that it was a "quality" regulator. So...I could replace it outright and eliminate it as a possibility.

Just to toss out one more "what-if": the battery only started this problem (building up gas and gently fizzing through the caps) while the car sat idle. I was putzing around with replacing the headlight switch, so I spent lengths of time turning the ignition key, playing with wires, checking and rechecking what wires went to what lights...in the midst of that putzing around, might I have caused a mild short circuit that would have stirred up the battery chemistry, and caused it to do this kind of fizzing? I've done the dramatic short circuit thing in other situations in the past where, you know, you make a spark and a poof of smoke where it becomes immediately obvious you're doing something stupid.

If the voltage is too high and the generator is overcharging the battery will "fiz" and boil over when driving at a steady speed. Will not occur when generator is not charging such as at idle or engine not running. It will occur when driving at a steady speed and ammeter way to the + side.

Hi guys -

I took off the voltage regulator and took a quick look. It's slightly corroded on one side and the cover seal has a missing piece, so, I'm just going to go ahead and buy a new one for piece of mind.

If you don't hear back from me, that's good! Silence = golden.

Cool and good luck!

Hi gents -

Put in a new voltage regulator and new battery this weekend. Fires up and runs like a champ with no more wide swings on the ammeter, so, whether it was the old regulator at fault, or the battery that wouldn't hold a charge, I've got 'er licked either way!