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From: jackh@zehntel.UUCP (jack hagerty)
Newsgroups: net.auto
Subject: Batteries and concrete floors
Message-ID: <1648@zehntel.UUCP>
Date: Thu, 25-Oct-84 17:45:06 EST
Article-I.D.: zehntel.1648
Posted: Thu Oct 25 17:45:06 1984
Date-Received: Sun, 28-Oct-84 06:16:28 EST
Distribution: net
Organization: Zehntel Automation Systems Inc, Walnut Creek CA
Lines: 35



> If I may tag along on your question, Dave, I have heard that
> you should "never ever never" store a lead-acid cell on cement.  This
> will cause it to discharge.  For the life of me, I can't think of a
> reason...  Anyone heard of this before, and know of a reason???

This "urban legend" has been around nearly as long as the storage battery.
A few years ago one of the major magazines decided to put it to the test.
(It was R&T, I think. It doesn't sound like something that C/D or MT would
do. I'll look for the article tonight; if I find it I'll give a reference)

Basically, the test went like this: they took two identicle batteries, fully
charged them both, placed one on a plywood workbench and the other next to
the bench on the concrete floor. After several weeks the batteries were tested
and the state of charge was identicle, within measureable limits.

If so, then why the "legend" in the first place? I can think of two reasons.
First, batteries do discharge with time if they're not used. It's easy to 
put a battery on the floor in the corner of the garage and forget about it.
When you go back (8 or 10 or more months later) the battery is dead! "Wow",
you say, "that concrete floor sucked all of the electricity right out of 
this battery!"

Second, concrete is a good conductor of heat as well as being a huge thermal
mass. (Anyone who has stood around in the garage in winter will attest to
this). This will certainly draw all of the *heat* out of a battery, at least
down to ambient. Being chemical devices, batteries are much more sluggish
at lower temperatures (right, snow belt people?).

The above are pure conjecture on my part, but I've yet to see anything better.

                                     Jack Hagerty, Zehntel Inc.
                                     ...!ihnp4!zehntel!jackh