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
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?
Former slayer of dragons; practice now limited to sacred
The only explanation have ever seen is that back in the old days (the
1920s etc.) the battery cases then used were more porous than modern
plastic ones and in some instances and in damp conditions dampness
could cause lime products in the concrete to leach into the battery
acid! So the myth about not storing on concrete has continued into
If the battery is not fully charged when put away and/or not given a
refresher or put on trickle charge every few months it is likely to be
useless a year from now. Sticking it on a refresh charge every few
months for a few hours at a low charge rate will be best chance for
Measuring the voltage alone is not a very good indication of state of
charge or overall condition of a lead acid battery. But the on 'load
test' performed by the auto parts store should have been a good test.
DO NOT NOW LEAVE BATTERY discharged.
Hardly a pure fantasy. Old battery cases were made of hard rubber
containing carbon. They wrere, in fact, somewhat porous, and storing
them on concrete DID ruin the battery.
This problem existed a lot more recently than the 1920's, but modern
batteries are not cased in rubber.
The concrete stuff is a persistent urban myth. I have yet to
hear a chemical or electrochemical explanation for the claimed
effect of concrete. I know someone who worked at a place
manufacturing automotive batteries, and he says that's a myth.
The thing is to keep it charged. It will self-discharge, and need
its charge topped off something like monthly.
People who have batteries die from sitting on concrete have them
die because they sit long enough to get badly discharged, and then
a bad sulfation process occurs. On concrete is merely where automotive
batteries mostly meet such a fate.
- Don Klipstein ( email@example.com)
www.batteryuniversity.com has good info, so do other sites you should
google. Wash it real clean thats partialy how it discharges, and as I
understand it must be maintianed 100%, a battery maintainer is what
you need. Ive ruined many batteries by not using a maintainer from
sulfation, it happens real fast. 12.5v isnt charged, its sulfating
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
On Thu, 30 Jul 2009 20:19:12 -0400, firstname.lastname@example.org wrote:
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.
On Fri, 31 Jul 2009 08:23:27 -0400, "Stormin Mormon"
I doubt it ever gets cold enough anywhere in the continental United
States to freeze a fully charged car battery. If you disagree, please
As I pointed out, storing a battery in a warm place will shorten it's
On Fri, 31 Jul 2009 18:38:18 -0400, "Stormin Mormon"
Lack of curiosity is a sign of low intelligence.
Meanwhile, a fully charged battery won't freeze anywhere in the
continental US. - Of course if you store it on the polar caps of Mars
it will likely freeze.
It'll freeze if you put it in the right kind of refrigerator, anywhere in
A fully-charged battery will freeze somewhere around -75°F. At a 50% charge,
it'll freeze at about +5°F. Further, a fully-charged battery will loose
about 1% of its charge per day at room temperature.
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