# Battery on Concrete...UL? **URL:** \ **Category:** Factual Questions\ **Created:** [July 16, 2000, 7:10pm UTC](https://boards.straightdope.com/t/battery-on-concrete-ul/25756 "2000-07-16T19:10:37Z")\ **Posts on this page:** 5\ **Page:** 2
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [July 24, 2000, 5:02pm UTC](https://boards.straightdope.com/t/battery-on-concrete-ul/25756/21 "2000-07-24T17:02:04Z")
Oops. I forgot the editor automatically removes leading spaces, so my ASCII diagram looks even worse than I imagined. Just picture a bird’s-eye view of a car battery with the “+” terminal positioned on the left and the “-” terminal on the right. “A” is the top-side of the battery (12:00); “B” is the right-side (3:00); “C” is the bottom-side (6:00); “D” is the left-side (9:00). ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [July 24, 2000, 5:03pm UTC](https://boards.straightdope.com/t/battery-on-concrete-ul/25756/22 "2000-07-24T17:03:21Z")
This is an interesting angle that would have never ocurred to me but I doubt this would have any effect. The liquid within the battery would prevent any significant temperature difference from forming unless you had some _serious_ outside temperature conditions. But the thought is clever. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [July 24, 2000, 5:32pm UTC](https://boards.straightdope.com/t/battery-on-concrete-ul/25756/23 "2000-07-24T17:32:46Z")
Sailor: You may be correct that this is non-issue; I don’t know. Has anyone studied this and published results? We should be able to do a rough calculation to find out the magnitude of current that would flow due to a temperature gradient. I suppose we would need to know the following: - Voltage vs. temperature curve of a lead-acid battery - Source impedance of a cell - Thermal conductivity of a cell (or acid) I don’t know what the above values are, but I do know one thing: The source impedance is quite low. It wouldn’t take much of a voltage gradient to cause a significant current to flow. ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [July 24, 2000, 5:49pm UTC](https://boards.straightdope.com/t/battery-on-concrete-ul/25756/24 "2000-07-24T17:49:37Z")
As I say, i thought it was quite ingeneous to think of this angle because it would have never ocurred to me. On the other hand I just cannot see it affecting the battery in real life conditions. I think it would be difficult to have a temperature gradient _inside_ a battery cell of even a fraction of a degree. It is relatively well insulated and full of liquid that would soon cause convection. that’s just my WAG. If you have anything more concrete I’d be interested. I have seen batteries installed in places with temperature differentials and never seen any measures taken to avoid them. That is why this angle would not have ocurred to me. ---
**Author:** ![Saltire](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saltire/32/553_2.png) [@Saltire](https://boards.straightdope.com/u/Saltire)\ **Post date:** [July 24, 2000, 6:17pm UTC](https://boards.straightdope.com/t/battery-on-concrete-ul/25756/25 "2000-07-24T18:17:26Z")
If your concrete was radioactive, the main effect would be to ionize the air. This would make it more conductive, and could allow the battery to discharge faster. But I doubt it would be much of an increase. But keeping the battery cooler would make it discharge slower. I think this effect would be more significant. So, as long as your garage floor isn’t really ‘hot’ in the radioactive sense, and is ‘cool’ in the temperature sense, I think there would be a net increase in charge life, compared to a warmer spot. However, I doubt that putting a board under the battery would warm it. If the temp in your garage shifted a lot, the insulation value of the wood would keep the battery from cooling to a new, lower temp as quickly, but it wouldn’t change the situation in a room that kept more of a steady temp. [Previous page](https://boards.straightdope.com/t/battery-on-concrete-ul/25756.md?page=1)