Thread: Why do my batteries leak?

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A while back I had a '76 Cadillac that would blow the top caps off the battery (two different batteries). Made a nice "gong" sound hitting the hood when it happened Turned out to be a bad diode in the alternator. Replaced alternator, problem solved. Although it sounds you're on your second alternator already, may be good to give it another look....

-Chris

Originally Posted by DennyW

If it stays at 14.2 all the time, it is over charging. I*f a battery has a bad cell, or 2, it will want to charge all the time. Double check the battery as far as the cells being good.

Each cell is 2.2 volts on a 12 volt battery. If 5 of those cells are 2.2, and the 6th one is less than 2.2, all the other cells will try to charge that cell to make it even. Like a bucket with holes, and you are trying to keep it full, but it doesn't fill up.

The Battery has to be good, and fully charged to test the charging system correctly.

actully 2.1V per cel. 12.6v fully charged

oh yes to check for a bad diode in an alt, turn a DVOM to A/C volts, start engine, hook positive to the alt output wire, and ground to the alt case, anything over .5V A/C indicates a bad diode.

Originally Posted by Matt167

oh yes to check for a bad diode in an alt, turn a DVOM to A/C volts, start engine, hook positive to the alt output wire, and ground to the alt case, anything over .5V A/C indicates a bad diode.

you keep saying DVOM....is that a DVM ? same as a DMM ? I'm guessing it is....I'll try that too.

Digital Volt Ohm Meter. big company that makes them is Fluke.

Originally Posted by DennyW

Your getting to many what if's right now.

Thanks for the additional info...

Either you guys are helping to fast or I am working too slow. ...I'll get back in a few days after I fix my bisc and am done with the battery.

Many batteries and a change of altenator. looks like the problem is not the charging circuit. The problem is heat. Winter or summer, it's the same heat source. You've got the battery too close to the exhaust manifold. There should be a tin or aluminum cover around the exhaust manifold. It's there to protect the battery. Most guys tear it off because it's ugly, and gets in the way when changing plugs. Put some kind of metal barrier between the exhaust manifold and the battery to absorb the heat. If the battery is mounted forward next to the radiator...Same problem, same solution.
Had the same problem with my Duster, and my Pinto. I was the one who tore off the ugly covers. Couldn't figure out the problem with the Duster, so I sold it. Found the problem in the Pinto, it had burned a hole in the side of the battery.

Quick question: As you know, the battery in question was moved from my truck to my car for trouble shooting (my car's wiring) last saturday. At that time, it had 12.2v and passed a load test (barely, border line weak). Well, last night I went out to work on my lights again and first measured the volts @ 12.2. I ran through the running lights and blinkers, all good. I turn on the headlights and my blinker slowed down. I immediately checked the battery again and it was at 9.5v
I shut off the lights, disconnected the battery, and it slowly crept back up to 12v. Does that seem to indicate a bad or weak battery? I would not think it would lose that kind of power over five days. Total "on" time between saturday and last night was only about an hour or two and I pulled the cables every time I finished. I think it's bad?
I put it on a trickle charger and left it alone.

I was gonna check the water/acid level but it says "do not remove caps"...

I need a battery for my biscayne anyway so I figured I would replace the one for my truck (again) at the same time. I admit, I hate messing with large acid filled automotive batteries. Something about caustic substances that makes me uncomfortable...I don't know enough about them.

Yeah but what I'm saying Denny is that the battery came straight out of my truck with almost a full charge. In the past I've left my lights on all day and still had juice to start the engine. In the bisc it was pulling 14.7 amps with all of the lights one (high beams included) and most of the two hours or so I was using it, it was just the running lights.

The engine was not running (it a fresh build, I am borrowing the battery to make sure my electrical is 100% operational before I fire it up). I will check the water tonight. What do I add if it is low? Regular water? If not, where do I get the stuff to add?

I know it all sounds confusing. I ought not to troubleshoot a donor battery, from another vehicle, with a possible charging system problem, while I am using to diagnose the electrical system in the "battery borrowing" vehicle... ...need to get my ducks in a row.

No need to reply (except for the water question). I'll remove the battery in question, put it back in my truck, and buy a new one for the biscayne. I'll make all of the checks we have discussed, regarding my truck, and get back with you.