Batteries on concrete

[slomobile]

Some mechanics say to never put batteries on concrete, just as many say it is an unfounded superstition. I've heard it blamed on temperature changes, and on current leaking away to "ground", which sets off BS alarms.

With my prone chair disassembled, I have the old but still barely functional MK gel batteries sitting on my garage floor. They seem to be fine, charged somewhat regularly, resting in the steel removable permobil battery tray over the summer. But I've never had a lead motorcycle battery live through the winter sitting on concrete, even if sitting on foam insulation. They almost always last if left in the bike disconnected. I've had 4 big high quality lead UPS batteries die within a month sitting on concrete.

With all the experience here, someone must know. What is it about concrete floors that kills batteries? Does it just happen to lead batteries? Are lithium batteries affected? Or is it a myth and old forgotten batteries are going to die wherever they are, and that is usually the floor?

[daveonwheels]

parasitic drain

[slomobile]

parasitic drain

Well, yeah. But what is the parasite?
The concrete?
These battery terminals aren't connected to anything.
If its just normal self discharge rate, that isn't parasitic.
If its discharging through gunk on top of the battery, its parasitic, but not related to concrete.
If it's parasitic, and due to the bottom (not terminals) sitting on a concrete floor, how is it happening?

[Williamclark77]

Old wives' tale that doesn't apply to any modern batteries in properly insulated plastic cases. Batteries from 75 years ago were not as well insulated and could experience parasitic loss sitting on wet concrete.

[Burgerman]

All batteries discharge over time. And with lead its quite fast. With DECENT lithium its very slow. But all the cells will discharge at different rates putting them out of balance over time which is why top balancing is essential. A chair has a parasitic load though as well. And so do the BMS that some people use.

[Burgerman]

Some mechanics say to never put batteries on concrete, just as many say it is an unfounded superstition. I've heard it blamed on temperature changes, and on current leaking away to "ground", which sets off BS alarms.

It should. That old wives tail has been around since batteries were made in wodden boxes. And even then it makes zero sense.

With my prone chair disassembled, I have the old but still barely functional MK gel batteries sitting on my garage floor. They seem to be fine, charged somewhat regularly, resting in the steel removable permobil battery tray over the summer. But I've never had a lead motorcycle battery live through the winter sitting on concrete, even if sitting on foam insulation. They almost always last if left in the bike disconnected. I've had 4 big high quality lead UPS batteries die within a month sitting on concrete.

The battery doesent care how high, what its sat on, or much else. It only cares about being sat at a temp that is cool,(and a fully charged battery wont freeze at any temperature anyplace on the planet). And that it is kept at 100% fully charged. Since ALL lead batteries self discharge internally albeit at different rates depending on type, and age, and any impurities in there, that means ideally at a continual low safe float charge corrected for temperature. Something like 13.25 to 13.3V. But OUR batteries, gel, or quality deep cycle AGM, have a lot slower self discharge than say your old motorcycle starter battery.
The MK gel or Odyssey for e.g has a 10 year or 12 year standby life. If looked after. Your bike batteries probably 3.

With all the experience here, someone must know. What is it about concrete floors that kills batteries? Does it just happen to lead batteries? Are lithium batteries affected? Or is it a myth and old forgotten batteries are going to die wherever they are, and that is usually the floor?

It was never true. Its all nonsense.

[ex-Gooserider]

How true it is at all is debatable. I have seen reputable sources say that back in "ye badde olde dayes" when battery technology was not as good, and the battery cases were made out of materials that weren't as good insulators, and had vented caps that let acid fumes build up around the terminals, etc. there was more of a path for trickle current flow...

At least in theory, damp concrete was enough of a conductor that it gave an added path for that current, so increased the rate of self discharge... How much this was really a factor is probably quite questionable. (Interestingly one would expect that putting the battery on a metal surface would be worse, but nothing is ever said about that...) At any rate w/ modern sealed batteries with cases made from modern plastics that insulate better, it is not a problem....

ex-Gooserider

[Burgerman]

The battery materiels inc wood and rubber...
So in very early batteries the case would in itself cause a self discharge of the cells. Adding a concrete floor would appear to make very little difference to that... Stick a multimeter on concrete and its a better insulator than that wooden case! Unless its wet. Even then its debatable.

Anyway we dont have batteries like that in this century. Or most of the previous one.

[Scooterman]

I wonder whether it be because people might store batteries out of the way on the floor in the corner of a garage or shed say. Where it's a lot easier to forget about them, and forget to periodically charge them. As the saying goes, "Out of sight, out of mind".

[Burgerman]

Who knows. But any claim to being a fact must at least have some logical rational or possible methodology as a way to show it is possible. To go along with it or its no better than the many old wives tales.

[Scooterman]

Yes, like sit on a cold surface and you get piles!

I don't think you do.

[Burgerman]

I dont either...

[Scooterman]

Ha Ha, very good!