On Fri, 28 Jan 2005 16:26:31 GMT, y_p_w > wrote:

>Specifically, the order I recall is dead battery positive to good
>battery positive. Then good battery negative to ground AWAY from
>the battery; ground is any metal part at least 8 inches from the
>dead battery. The idea is that a spark when the circuit is
>completed could potentially ignite any flammable gasses coming
>from the battery.

I've seen this (battery blowing up) happen twice. Both times it was
Winter and the battery had frozen because of a charging problem. A
third time I saw a battery blow it's cell covers off (they weren't
really installed, just laying on the battery) because of an
inadvertant spark while the battery was being heavily charged.

In the case of the first frozen battery, no spark occured near the
battery, all connections had been made and the owner was attempting to
start the car. The battery just blew apart. It was morning after the
guy had driven up to the ski resort where I was working and it had
gotten really cold that night. His battery just managed to get him
into the dooryard. He parked it overnight, intending to deal with the
dead battery the next morning... instead it dealt with him.

The second frozen battery was being charged after the car had been
towed to the shop because the battery was dead. The mechanic working
on it was leaning into the engine compartment when the battery
exploded like a grenade. He was only nicked on his forehead. He was
very very lucky guy because pieces of the battery scattered across the
entire 8 bay shop.

I've had bad luck trying to make a good ground connection on the dead
car away from the battery and getting a good enough connection to make
things happen. There always seems to be too much resistance to get
the engine spinning fast enough to run.

Switching the negative clamp directly to the battery's negative post
usually does the trick, but due to my experences with exploding
batteries, I'm always either REALLY shielding my face when I do this,
or removing the battery cell caps (if it has them) to prevent an
explosion in a closed container. On the other hand this virtually
guarantees that there will be explosive gas floating around unless you
drape a cloth across the battery. Working around charging batteries
still makes me nervous, 22 years after I stopped being an auto
mechanic.

Corky Scott