FredWehmeyer

As indicated, I was asked to weigh-in on the battery-on-concrete' issue and other battery related issues. For credibility sake, I've been designing, manufacturing, and testing all types of batteries for over 30 years. I've often been asked about storing batteries on concrete floors and the best way to answer is No it's not an old wives' tale because Old Wives' Tales don't have any basis in fact.' Not storing batteries on concrete does have some historical basis, it just doesn't apply to modern batteries. In the old days' (>30-40 years ago) batteries were built in fragile wooden, glass, or brittle hard rubber containers that often cracked and leaked electrolyte (sulfuric acid). The acid would not only damage concrete floors but could also cause a short circuit if it electrically connected two or more cells externally thru the electrolyte. This could cause the battery to discharge during storage. To offset this tendency, battery gurus developed the concept of placing wood or other absorbent insulators under the batteries to absorb the acid and insulate them from the floor and from themselves. Modern battery containers are now made from tough polymeric materials like polypropylene that resist cracks and abrasions and seldom leak. However, if you plan to place a battery on a surface that could be damaged by acid, I recommend putting an absorbent insulator (wood, plastic, newspaper, etc.) under it. I once knew an unfortunate battery salesman who was making a final presentation for a lucrative contract to a large retailer. He had placed a live, prototype battery in the middle of the retailer exec's mahogany desk for discussion purposes and after negotiating the contract, picked it up to leave. It left a noticeable acid footprint in the mahogany. He got two orders: Get Out and Stay Out!' I did notice one interesting comment about the effect of concrete on lowering the battery temperature. This would have a positive effect on storage since batteries self-discharge more slowly at lower temperature (battery self-discharge rate doubles for 10'C or 18'F increase in battery temperature). Batteries should always be fully charged prior to storage and deep cycle batteries should be recharged every 2-3 months during storage for best life. Regarding the question of overcharge damaging batteries, the answer is yes. Extended overcharging can lead to over-heating and water loss reducing performance and life. If the charger does not have an automatic turn-off or turn-down (float) mode, an easy way to prevent inadvertent overcharge is to use a simple wall timer set for 12 hour max time. Hope I've been able to help, Fred Wehmeyer Director of Product Engineering U. S. Battery Manufacturing Company Augusta, GA 30907