Car: '73 MGB, 2 6 volt batteries
The short form:
What would cause a battery to get real hot and blurt water out of
the vents in the caps?
The long form:
Last night as I was driving up El Camino Real (30mph avenue with
lots of stoplights) I started to notice some electrical problems.
First the tach didn't work right, it moved slowly and stayed at around
2500 most of the time (and I was varying my speed). Then while stopped
I noticed the dash lights were out and the signal wasn't flashing
regularly. Fortunately I was close to home. Above idle things seemed
to work ok.
At home I shut the engine and then could not restart it, little power
to the starter, like a dead battery. Since the car was just running
I suspected the charging system. So I checked for loose wires, cleaned
some ground straps, but didn't go further. Then I opened the battery
compartment and found one battery was pushing water out of the vents in
the caps. And the battery was hot. The other one was cool and normal.
I checked the water level in both batteries, it looked ok but I pulled a
little out of the hot battery, then disconnected one lead to open the
circuit and went inside. Three hours later the battery was still quite
warm, I pulled it out of the car and set it on some paper for the night.
This morning it was cool.
Previous symptoms:
The car usually is not easy to start in the morning, especially after
a few days sitting. I've checked for electrical leaks (ammeter between
one post of the battery and a lead, pull fuses, etc.) and found none.
So my conclusion is I have a bad battery. What do you think?
Runaway reaction? Shorted cell? Or is it the charging system?
-Dan Dasaro
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