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Re: Dead Batteries and Electron Flow

To: mgs@autox.team.net (mgs)
Subject: Re: Dead Batteries and Electron Flow
From: todd@nutria.nrlssc.navy.mil (Todd Mullins)
Date: Thu, 2 Nov 1995 09:01:14 -0600 (CST)
W. R. Gibbons writes:

> On Wed, 1 Nov 1995, Dean Craig wrote:
> 
> > direct contact with it to cool. When the weather warms up the cold concrete
> > and battery are consideraby colder than the surrounding air and will stay
> > that way for quite some time. This causes condensation to form on the
> > exterior of the battery. The condensation creates a current path from the
> > positive terminal of the battery to ground (the damp concrete) and the
> > stored charge in the battery is slowly drained away. Condensation will also
> 
> I think this is a great idea.  Except, the only current flow that can
> discharge the battery is the current flow between the terminals.  Positive
> charge can't leak off to ground all by itself.  Law of electroneutrality 
> (passed by congress in 1892) says it can't happen.  

Right.  You'd have to have the negative terminal connected to earth, or
something silly like that.

All this talk is conjuring images in my poor feeble brain of some sort
of electron fence placed between the terminals, so that the electrons
can't go visitin' from one terminal to the other.  Except the really
determined ones would probably just dig under the fence and escape.
Maybe an electron leash law?

> Still, if you consider that the battery generally is covered with crud, 
> some of which is salts, and water condenses on the cold case, and the 
> salts dissolve to make a conducting solution, and there is a trickle of 
> current between the posts--it makes sense to me.

Anybody who likes going barefoot knows that concrete stays colder than
the ambient air most of the time.  Perhaps this whole battery/concrete
thing simply boils down to the zeroth law of thermodynamics (or whatever
number it has; the one that says that objects in contact tend towards
the same temperature):  a battery on the cold concrete floor stays
colder when the surrounding air warms up, condensation forms (whether
there are salts or not, but the salts help conductivity), and electrons
hit the road.

-- 

Todd "keep 'em separate but equal" Mullins
todd@nutria.nrlssc.navy.mil     On the lovely Mississippi (USA) Coast

'74 MGB Tourer

"A life lived in fear is a life half lived."

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