Re: Lead-Acid batteries and concrete floors

["Rich Weiss" <RichHeidi@TechHeadNet.com>]

I still think you are dealing with "urban legend"
Someone thought up a "plausible sounding" scenario to support the old
legend, which had been true. Since it is not true with today's materials, a
new explanation was needed. If anything, I think you would find, having the
battery sitting on a "thermal mass" would stabilize it's temp, and result in
more uniform temps and less discharge.

[BY THE WAY, YOU DON'T HAVE TO MAKE STATEMENTS LIKE THE FOLLOWING.:

>>>Umm, read the WHOLE message.  Nothing is permeating the case except cold,
> and plastic isn't immune to cold.<<<

You asked for opinion >> "So what do you folks think, sound reasonable?"<<
and I gave my opinion based on 30 years of  servicing storage batteries]



----- Original Message -----
From: "PETER VANDERWAL" <peterv@peoplepc.com>
To: <ev@listproc.sjsu.edu>
Sent: Friday, March 30, 2001 10:55 PM
Subject: Re: Lead-Acid batteries and concrete floors


> Umm, read the WHOLE message.  Nothing is permeating the case except cold,
> and plastic isn't immune to cold.
>
>
>
> > That used to be a true statement, when battery cases were rubber and
> pitch.
> > They would seep acid and form a conductive layer with the concrete,
> > resulting in a parasitic discharge. Today, with impermeable plastic
cases,
> > it doesn't matter.
> >
> > Rich
> >
> >
> > ----- Original Message -----
> > From: "VanDerWal, Peter" <vanderwp@fhu.disa.mil>
> > To: <ev@listproc.sjsu.edu>
> > Sent: Friday, March 30, 2001 4:32 PM
> > Subject: Lead-Acid batteries and concrete floors
> >
> >
> > > I'm sure we've all heard that Lead-Acid batteries will go dead quickly
> if
> > > you store them on concrete floods (i.e. in the garage).
> > >
> > > I'd pretty much assigned this to the "Old Wives" tale section since
> nobody
> > > could provide me with a credible explanation of why this was so or any
> > > verifiable tests indicating it was true.
> > >
> > > Well I was going through some old magazines and I found a letter to
the
> > > editor that actually provided a reasonable sounding explanation of why
> > this
> > > happens.  I'm still not sure that they do go dead quicker on concrete,
> > since
> > > I've not heard of anybody testing it, but if they do this sounds like
> why.
> > >
> > > The author pointed out that concrete floors tend to be colder than the
> > > ambient temperature.  I've noticed this, I believe it's due to
> > evaporation.
> > >
> > > Anyway with the battery sitting on the floor, the bottom of the
battery
> > will
> > > be colder than the rest of it.  This causes temperature stratification
> of
> > > the electrolyte (different temperature layers).  The different
> > temperatures
> > > in the electrolyte leads to different specific gravity with the colder
> > fluid
> > > at the bottom having a lower specific gravity than the warmer fluid on
> > top.
> > > The different specific gravities will cause different voltage
potentials
> > > across the tops and bottoms of the plates.  With different voltage
> > > potentials current will flow inside the battery and cause it to go
dead
> > > quicker.
> > >
> > > So what do you folks think, sound reasonable?
> > >
> > > P.S. If true I would suspect this has less effect on AGMs and Gel
Cells.
> > >
> > >
> > >
> >
> >
>
>
>