Re: Wet vs. Sealed Safety

[XURQ03A@prodigy.com ( LEE A HART)]

Chris Meier asked:
>If one or more batteries are dead shorted, is one type safer than the other?

Shorting a fully charged battery is likely to result in:

 - a blown fuse (you *do* have a battery fuse, don't you?)
 - a melted terminal, wire, or screwdriver (whatever caused the short)
 - boiling electrolyte geysers (the water in the cells boils)
 - a steam explosion (the electrolyte turns to steam, the vents can't
   release it fast enough, and the whole case bursts)
 - a fire (caused by intense heating of whatever is carrying the current)
 - a good photo opportunity :-)

Obviously, full charge is worse than partially charged. A really low
resistance short is worse than a partial short. A low internal resistance is
worse, because the currents are higher and things happen much quicker and more
violently. Higher kilowatt-hour packs (more batteries, more volts, more
amp-hours) are worse because there is more energy available.

Sealed batteries are not intrinsically any worse, but tend to have lower
internal resistance and smaller, restricted vents. They aren't as likely to
produce geysers, but can go directly to exploding case failures.

But batteries in general are safer than the gas tank in a car, simply because
you only have a few % of the total energy storage.

Lee Hart                     If you would not be forgotten
4209 France Ave. N.          Soon as you are dead and rotten
Robbinsdale, MN 55422 USA    Either write things worth the reading
phone (612) 533-3226         Or do things worthy of the writing
e-mail XURQ03A@prodigy.com   (Ben Franklin, Poor Richard's Almanac)