On Wed, 11 Dec 2002, John Rodgers wrote:

> Most acid electrolyte batteries "Fume" just an imperceptable bit, and
> the result is an almost undetectable coating of electrolyte on the case,
> providing a direct circuit to "Ground", in this case, the concrete
> floor. Result - dead battery. The wood acts as an insulator.

The floor isn't 'ground' to the battery, because no part of the battery is
connected to it.  Any discharge path would have to be from pole to pole.
That's going to be across the top of the case; what the battery is sitting
on doesn't matter.  A thin surface film also has a high enough resistance
that at 12V it isn't going to be significant.

The ground is only electrical 'ground' for systems that are connected to
it elsewhere -- for example, the U.S. power grid is ground-referenced, and
neutral conductors all have a path to ground somewhere.  This isn't true
of a battery that's sitting all by itself.

             _ _
  __ _ _   _| | |  | David M. Brodbeck (N8SRE)              Ypsilanti, MI
 / _` | | | | | |  +-----------------------------------------------------
| (_| | |_| | | | @ cyberspace.org
 \__, |\__,_|_|_| "To the optimist, the glass is half full.  To the
 |___/             pessimist, the glass is half empty.  To the engineer,
                   the glass is twice as big as it needs to be."