On Thu, 30 Jul 2009 20:19:12 -0400, wrote:

On Thu, 30 Jul 2009 18:52:57 -0400, wrote:

On Thu, 30 Jul 2009 14:11:31 -0700, "CWLee"
wrote:


I've ended up with an extra car battery. Took it to a local
auto parts store, to see if it was worth anything. The
clerk tested it and said it was "almost as good as new." He
said it showed 12.5 volts after a load dropped it to 11.5
and then it came back. He said it was in good shape. So,
maybe I should keep it. It is 5 years old, with a warranty
for 6 years. I told the clerk I'd just keep it in the
garage as a spare, and he said that was a good idea, but not
to let it sit on concrete. He said if it was stored on
concrete it would "drain away" to nothing within a couple of
weeks. I asked "What about placing it on wood?" He said he
didn't know about that, but for sure not to store it on
concrete.

Do any of you have any evidence to support his idea that
storing a good auto battery on a concrete floor would damage
it? In general, what is the best way/place to store an
unused but good auto battery?

Thanks.

In the old days, batteries had hard rubber cases and setting them on
concrete could result in a ruined battery. Modern Batteries are not
made of rubber any longer, so it really doesn't matter. I usually put
mine on a piece of wood just out of habit, I guess. The more important
issue is to make sure you keep it charged and the water at the proper
level.

The concrete "myth" persists because the battery might still damage
the concrete if there is any residual acid on it or you boil some out
overcharging it.
The piece of wood is just for peace of mind.

On the other hand, placing the battery directly on a slab might keep
it cooler, and slow down the chemical reaction. That would help
prolong the life of the battery. I keep my boat batteries in the boat
all winter in New England for just that reason. I give them a charge
about once a month. As long as a battery is kept charged, it will not
freeze. It is better for the batteries than bringing them inside.