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Mon Sep 01, 2008 4:41 pm

I purchased our '74 Vert earlier this summer. Today I experienced a problem with the battery.

About 15 miles into a 20 mile drive we began to smell a strong sulfur smell. Once I got to our destination we quickly found the source - boiling battery, sulfuric acid. This has never happened on similar length trips so I am not sure the cause.

Old battery?

Overcharging? How can I tell?

Before I run out and get a new battery (which I am going to do), I want to make sure I get the root cause of the trouble.

It looks like the main electrical was redone by a previous owner. The battery simply has a positive and negative connection. No ground. Is that normal?

Thanks.

Mon Sep 01, 2008 4:50 pm

Is there any water left in the battery? That should be your first check. Distilled water only if it need some.
Got a voltmeter? Voltage at idle should be around 12.6-8. At 2500RPM and above is really shouldn't be more than 13.5 or so.

Your last statement about no ground tells me you should take the car to someone who knows what they're doing. But FYI, the negative connection IS ground.

Mon Sep 01, 2008 5:14 pm

Kalajian wrote: The battery simply has a positive and negative connection. No ground. Is that normal?

Thanks.

as normal as it gets.

not exactly sure without looking how a 74 is wired but my 70 goes like this.

from the battery:

negative - to ground

positive - has 2 wires coming off of it, 1 goes to the starter and the other goes to the voltage regulator.

those voltage regulators can be adjusted buy i highly advise against it!!! buy a new one, they are only around 40 bucks or so.

Mon Sep 01, 2008 5:33 pm

both indications are you r at full charge all time ,regulator probably-check for stuck points.

Mon Sep 01, 2008 7:16 pm

the 74 should have had (from factory) the externally regulated(solid state) alternator(usually Motorola)... at idle you should get 13 volts or so and up to 14.4 or so at 2000-2500 rpm's.... sounds like overcharging to me...

Thu Sep 04, 2008 12:18 pm

I appreciate the good words of advice.

Thu Sep 04, 2008 1:08 pm

Had same problem last year. Wicked sulfur smell and battery got hot hot. Symptom of overcharging. My 74 super still has the external voltage regulator. Bought a new one. Same problem!! Checked voltage output and got 17 volts. Too high. Went back to Advance Auto with the new bad regulator and they ordered me a new one. That one brought alternator output down to 14 volts - been fine ever since.
Interesting note on this - I though for sure my fairly new batter would be kaput. It wasn't - still using it and it is fine.

Mon Sep 22, 2008 6:41 am

Took out the old voltage regulator (wrong model and one wire was disconnected), put in the new/correct one and new battery. Voltage was perfect.

Thanks for the help.

My wife was surprised I could fix it.

Tue Sep 23, 2008 6:31 am

Just a thought. If you had the battery boil out some of the acid, you need to do some clean up. This is why the pans in that area rust out frequently.

Wed Oct 22, 2008 2:58 am

this is my problem... been driving me beetle around recently, strong sulfur smell, battery is hot hot, put my foot through the pan in front of the battery, relocated the battery to a plastic battery box behind the rear seat, booking it into a lecky next week... im guessing my regulator is gone