Wet Hot German Battery Compartment

[jalvani]

Took my ‘88 out for a long and occasionally hard drive through the mountains yesterday; after about 200-odd miles, the car started hesitating and died on the side of the road. Heard hissing from the trunk, opened up to find my month-old Interstate AGM battery spewing steam, hot to the touch, and deformed. The expected sulfur or rotten egg smell was present. Suspect either a faulty battery or a voltage regulator issue. Is there anything else I should suspect or inspect?

[proporsche]

you got it, overcharging..glad you stopped it could have been a problem...start with replacing the alt. regulator.Once you have it out inspect the rotor on the alt. for condition...and maybe change the battery

Ivan

[jalvani]

Originally Posted by proporsche

you got it, overcharging..glad you stopped it could have been a problem...start with replacing the alt. regulator.Once you have it out inspect the rotor on the alt. for condition...and maybe change the battery

Ivan

Thx, Ivan. Definitely changing the battery. Appreciate the advice.

[911obgyn]

Replace battery, could be faulty and under warrantee. Before driving anywhere check charging voltage at 1500-2500 rpm, should be 14ish volts and steady. If not pull alternator and replace regulator, have alt checked and rebuilt if necesary.
Check around your area for an auto electric rebuild shop.

[GH85Carrera]

Originally Posted by proporsche

you got it, overcharging..glad you stopped it could have been a problem...start with replacing the alt. regulator.Once you have it out inspect the rotor on the alt. for condition...and maybe change the battery

Ivan

Take your old alternator to a local rebuild place. Ask them to use the good bearings, and not any Chinese bearings. It will cost more, but you will get a better alternator.

Likely any alternator you get from the local stores will be a "rebuilt" unit done in some third world country and done as cheap as possible.

Having a local shop that has been doing it for years is a far better option. You can talk to them face to face.

Then get yourself a volt meter. I sent in my tach and had it modified like this.



The volt meter is right in my face, and I know it is charging at the proper range.

[darrin]

Jalvani -- have you noticed your dashboard and/or headlights "dimming" from time to time and/or random seatbelt warnings while driving? As others have indicated above, sounds like you're suffering from a textbook overcharging situation. However, important to note that (at least for me), the overcharging wasn't constant/continuous and would show up rather randomly. "Dimming" headlights/dash lights is a good example, as the lights aren't dimming, but rather returning to normal brightness AFTER an overcharging (going too bright) episode ends. To affirmatively diagnose the overcharge (if it doesn't show up with a voltmeter spot check), you'll either need to use a cigarette lighter-mounted voltmeter or a peak recording volt meter that will store peak voltage while monitoring.

[jalvani]

@GH85Carrera That's a slick solution. Dig it.

@darrin YES! Thank you. My radio would also cut out whenever I pushed the gas - realize now that's also likely overcharge related. I just hadn't gotten around to diagnosing it.

[jalvani]

Swapped the battery, still wouldn’t start. Had it towed down to my shop, and they bypassed DME to get it to start. Alt was putting out a full 17+ volts at idle. Awesome. Probably cooked the DME along with the battery.

They’re digging into repair/replacement options now.