We had a little discussion at a club meeting a month ago about batteries going dead if set on concrete. Here are a couple quotes from another forum that I pasted in here.
The first one is from the Car Talk guys, Tom and Ray.
Cut and paste from;
http://www.cartalk.com/content/colu...pril/06.html
"Dear Tom and Ray:
I am a middle school science teacher who is questioning a time-honored warning handed down to me from my grandfather. My wife and I were cleaning the garage when I was shocked to see a car battery resting on the concrete floor and not resting on wood. Pat, my wife, said, "What difference does it make?" My response was that the cement would drain the battery. Luckily for me, she didn't ask how, because I would have been stumped. Can the cement drain the battery, and if so, how? -- Dave
Tom: Well, Dave, you're a model for middle school science teachers everywhere. Why? Because you didn't try to fumble around and make up an answer like I would have!
Ray: You can completely ignore your grandfather's warning these days, Dave. In his day -- even in your father's day -- most battery casings were made of hard rubber. And because of the porosity of that material, battery acid would sometimes seep through the rubber and create a conductive path through the damp concrete, draining the battery.
Tom: But that can't happen today with plastic-cased batteries (which we've been using exclusively since about the time Nixon said, "I am not a crook"
. That's because molded polypropylene (a k a plastic), as you probably teach your students, Dave, is not porous at all.
Ray: And here's the interesting thing, Dave. The cooler the temperature, the slower a battery's rate of discharge. And because concrete is often cooler than its surroundings, leaving a modern battery on a concrete floor might actually make it last LONGER than leaving it on a wooden pallet! How do you like them apples? Copyright (c) 1999 by Tom and Ray Magliozzi and Doug Berman Distributed by King Features Syndicate, Inc."
Cut and paste from
http://www.inct.net/~autotips/battmyth.htm
"Battery Myth #2 Storing a battery on a concrete floor will discharge the battery.
"There is not currently a strong reason for avoiding contact of a battery with a concrete floor. The battery's contact with the concrete should not create a problem with the material in today' s batteries. If the battery is not clean, but has a surface layer of acid or grime which is conductive, the battery can be expected to self-discharge more rapidly than if it was clean and dry. Many years ago, the batteries were constructed with a wooden case around a glass jar with the battery in it. Any moisture on the floor could cause the wood to swell and possibly fracture the glass, causing it to leak. Shortly after the introduction of "Hard Rubber" containers, which were somewhat porous and of a less than ideal design, there was a chance of current to be conducted through the container of a high carbon content if the moist concrete floor permitted the current to find an electrical ground. These are two of the older reasons for not storing batteries on a concrete floor. There is no reference to avoiding storage on concrete floors in the Battery Service Manual published by the BCI. Their suggestion is appropriate for the current state of the art batteries built by reputable battery manufacturers. For more information on storage, see the AutoTips Battery Storage Tips page."
