New battery leakage or overheat on a 2002 GMC ENVOY

[sedar59]

2 new batteries in a week after changing the alternator.
What is the problem.
Please someone help.
Thanks.

[carriedi]

not enough information.

who checked out your battery, charging and starting system? what did they find? or... why did you change your battery? Twice.

[sedar59]

auto parts store hooked my car to their computer and told me that my alternator was bad.
it all started when my car would not start but it would crank when i jumped it, then I bought a new battery.
A month later the car battery light came on and it was saying "battery not charging", and the battery died on me 2 days after the light and the display came on. So I used a battery charger and let the battery charge for 2 days then I took it to the auto parts store for a free estimate, they told me it was the alternator, so I replaced the alternator.the next day my battery started to leak,3 days later I replaced the battery with a new one, that was yesterday, now the new battery is leaking also.
what is wrong with my car?

[carriedi]

where is your battery leaking from? Is the battery leaking from the body of the battery or is it bubbling out of the top from over charging? Who did your alternator? Did they bring the battery up to full charge and then check your charging system to see if it is charging between 13.8 and 14.2 volts? Did they check to see if you have a parasitic draw on the battery that the alternator is working overtime to make up for?

when the battery light comes on it is telling you that the battery is not being charged. That means that you will be running on the battery until the battery goes dead. Then you won't have anything left to get you car running. Two days is pretty good in the winter time, to run your car without a charge.

First thing any electrical shop will tell you is that your alternator is not for charging a dead battery. If you run your battery down and then change your alternator you should use a battery charger to charge the battery back up to full then you can drive the car. The alternator is to keep the battery charged up. Not to charge a dead battery. Otherwise it may cook your battery. A battery charger charges your battery at a specific rate over time. An alternator doesn't look at the time or the rate. It charges to the max until the battery if up and then it levels off to keep it charged. It remains barely charging until you add additional load like lights, fans, defroster, etc. then it charges to keep up with those loads too. Most alternators go from 60 amp to 200+ amp alternators. That means that they can charge at tremendous rates. So driving down the road at 2000+ rpm will try to charge a dead battery at the max amps. Too much amps for a battery all at once. So, inside the battery the cells will look like they are boiling because the charge is too high.

Battery, charging and starting are all tied together. They should be all checked together. Especially battery and charging.

[sedar59]

Its leaking from the top and the alternator gets super hot.
I think it's over charging the battery.
When they checked the car the battery was fully charged, I guess that is how they determined that the old alternator was bad .
I was told that I was lucky that the battery did not blow,so I parked the car will not drive it until it's fixed.
Thanks for your patience and input.
I hope that's all as far as that issue with my car!

[carriedi]

yes, overcharging can make a battery blow up. The charging make the battery "boil" or seem to boil by looking at the fluid in the battery. the chemical reaction is producing hydrogen gas. In small amounts (like normal charging) it's fine. But a severe over charge can cause excessive hydrogen and oxygen. Being confined in the battery and escaping into the engine compartment, a spark from an electrical component like a relay or solenoid or even a poor battery connection could cause a spark that could ignite the gasses. It's very rare but is does happen.

but yes, leaking out of the top could be a sign of overcharging. It usually means that your battery is being charged at 15 to 17 volts. (sometimes even higher if the regulator is stuck full on. I have seen is got to 19+ volts when the engine revs up)

make sure the battery has a good ground to the body and the engine. The pcm needs to see the battery with the correct voltages.