Bob wrote:
>Overcharging--charging at too high voltage--will cause a lead-acid battery
>to vent hydrogen gas
I have personal experience with this.
15 years ago I bought a used Chevy van for work. The previous
owner must be a hunter or fisherman who camped in the vehicle
regularly. He had installed a 2nd battery in the far left rear corner of
the cargo area for 12v accessories with the vehicle off. There was a
battery isolator up front with a wire running from it back to this
auxiliary battery.
So three days after buying the van, I'm driving around when I
smell an odd smell. I've been wrenching on cars for years and I knew all
the usual car smells - burnt electrics, melted v-belts, hot fluids,
overcooked brakes, etc. This was none of them.
I pull over to investigate. I get out of the van and pop the
hood. Can't smell the odor outside the van at all. I get back inside and
I can smell it.
I then notice that with the engine now off I can hear a soft noise
in the back of the van.
I exit the van and open the rear door.
The auxiliary battery is boiling. I mean BOILING. It had a
semi-translucent case and I could see bubbles in the acid. The noise was
the sound of boiling battery acid. So I was driving around with a van full
of hydrogen gas. One spark and I'd have been a rolling mushroom cloud on
the freeway.
You never saw someone grab a wrench and disconnect a battery so fast.
Don't know if it was the alternator or isolator that was the
cause. I disconnected the whole isolator system but the alternator died
two days later anyway.
Bottom line: overcharging really does cause out-gassing. And I'm
here to tell the tale...
Todd
Seattle,WA
'86 GTI, Red of course. (exciting racey car) 273,000 miles
'01 Golf TDI, silver. (new work car) 292,000 miles
'87 Golf, Polar Silver. (retired work car) 654,000 miles <- Gone to a new
home :(
http://www.pureluckdesign.com <-Ferrari & VW stuff
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