Old Husband's tale

This is probably true to some small extent, but even then, any reaction that takes place is on the outside of the battery and doesn't affect what's inside.

----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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On Tue, 16 Aug 2005 03:19:55 GMT, Ken Weitzel wrote:

I've worked with rechargeable batteries for many a moon and in my past experience have seen batteries that weren't properly isolated from ground contact drain much faster than those that were placed on rubber mats or insulated storage boxes. It includes nicads as well as traditional lead-acid.(including gel or dry cell.) When I worked in service as a photographer rechargeable modules were the lifeblood of virtually every type of photographic system we employed. From regular hand held cameras and strobe equipment the belly cameras on recon aircraft. We had a entire section of every ground base lab devoted to service and charging of all the various types of batteries we used. The one cardinal rule we had for batteries was never to leave them sitting on bare ground or concrete. Many of the larger modules even had their own storage cases, usually steel with a rubber coating inside. I distinctly recall on lab I transferred to having problems with the battey modules for their strobes suffering from short charge life and early death. They'd be charged every evening by the nightwatch and stored in a metal storage locker for use by morning crews the following day. The locker sat on a bare concrete floor and the plastic encased modules were simply stacked onto the painted shelves of the locker. None of the battery contacts came in contact with any conductive suface but if left on the bare shelves of the locker would would completely discharge in about 3 days or less. I ran a test by placing a fully charged battery in a heavy plastic bag and left it in the locker for a week, with another charged module sitting right next to it on the shelf. The bagged battery retained nearly all it's charge, the bare one was dead. After that we used a heavy plastic case with rubber mat to store the batteries and the problem was resolved.

I've been told by those more knowledgeable than I in matters of storage devices that there are instances where batteries can discharge due to grounding. I'm told it has something to do with relative humidity, also that sea air also promotes rapid discharge as well.(salt in the air?) My old man was an electrician who served his time on diesel boats.(submarines) and he was a big believer in isolating batteries from ground as well.

Yes but the car has four rubber insulators it sits on, the tires.

"Stirring the solution, would make for a much more uniform discharge curve. "

We've done some automotive work an I've noticed that nothing quite charges a battery like a car, perhaps because it moves ?

When we had a severely depleted battery on charge we would agitate it every few hours and at that time the ammeter reading would increase. I guess it knocked the bubbles off of the plates ?

JURB

I've noticed that, too, and always assumed it was bubbles, but perhaps it was concentration. Anyway, I jostle batteries being charged from time to time.

Both of these theories sound plausible to me. It could be bubbles, which form once the cell voltage reaches 2.4V, but I suspect that agitation is a more likely reason. Both probably play some part.

----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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Early car batteries had molded hard rubber cases that were less than perfect when it came to leaks. There is a 1/4" of concrete missing in the driveway next door where an old battery froze and developed hairline cracks. A month later the concrete around the battery was badly etched, and had had the 1/4" missing.

I don't think there is any disagreement that a battery with a cracked case will discharge, on concrete or elsewhere.

It's pretty clear that the question is in regard to a battery in good condition.

----------------------------------------------- Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA

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Possibly, which still makes it an old husband's tale since rubber hasn't been used for many a year - apart from on period batteries for classics, etc.

Well it cracked and leaked. Batteries should be protected from freezing in any eventuality.

I agree, but the old man who lived there was in the care of Hospice, and died that winter. I offered to take care of his place but he didn't want anyone touching anything, which isn't uncommon around here with someone in their 80s.

ok lets get one thing straight... we are talking about an old and i mean old "myth"... now years ago most cars had a chunk of wood under the battery to stop them from touching the steel.. I think this can all be cleared up with this thought.... new batteries ..not affected.... old batteries... well regular batteries from years ago required water top ups... they had a lot of seepage and evaporation and even spillage (oops i over filled it) and acid from a battery on concrete well its not pleasant... also if the battery was wet and dirty it could cause some current leakage however i would believe it still wouldnt matter what it was sitting on...

HERE IS WHAT I BELIEVE TO BE THE REAL REASON Long time ago someone stored a battery on concrete..... forgot to periodically charge it and it went dead ... so it was blamed on the concrete. because they forgot to charge it ....

" snipped-for-privacy@aol.com" bravely wrote to "All" (15 Aug 05 16:01:44) --- on the heady topic of "Old Husband's tale"

I had it explained to me that the difference in temperature between the cement and ambient air causes a vertical specific density difference in the electrolyte. This effect results in an a emf between the top and bottom of the plates which being conductive allows the usual battery chemical reaction to take place. Thus the battery slowly discharges over a period of many months (6 or more).

My thinking is that the black case exacerbates the problem by thermal emission and perhaps a white case would be less prone to the effect. BTW I've seen batteries in white cases. Anyhow, one idea I have had is to cover the terminals with their plastic caps then cover the top with a plastic bag and wrap the whole battery in aluminum foil. The idea being to force the battery temperature to be equal between top and bottom due to the good thermal conduction of the aluminum wrapping. Perhaps wrapping insulation around the battery would be just as good. But it's just an untested theory.

A*s*i*m*o*v

ZZ> From: snipped-for-privacy@aol.com ZZ> Xref: core-easynews sci.electronics.repair:339749

ZZ> Everybody, and I mean everbody puts down a barrier so when they put a ZZ> car battery down so it's not in contact with the ground, or cement. ZZ> Now normally the battery will sit on steel (in the car) which is a ZZ> conductor.

ZZ> They say that being on the ground kills the battery. How does a ZZ> nonconductor (concrete) being in contact with another nonconductor ZZ> cause this ? I refuse to believe it, but I do not put said batteries ZZ> on the ground. (I am a firm believer in Murphy's Law)

ZZ> Is this myth or mystery, and if true, just how in the hell can it be ZZ> true. I'm considered pretty advanced when it comes to electronics, but ZZ> this belief is so ubiquitous, that says there might be something to ZZ> it. ZZ> If anyone can shed some light on the process whereby the "ground" can ZZ> discharge a car battery please enlighten me. I've now heard this again ZZ> and have considered buying two brand new car batteries and chargers ZZ> with which to gain empirical evidence. Sometimes when I get curious ZZ> about something I have a hard time letting go of it.

ZZ> Can anyone either explain this so I can STFU, or debunk it so I can ZZ> run my mouth ? I've been hearing this for about 30 years now and have ZZ> dropped the subject numerous times. That is no longer good enough.

ZZ> Or are we talking about something like the pyramids or whatever ? I ZZ> know some physics but I am by no means a physicist. I'm having a hard ZZ> time believe this "myth" and I would like it cleared up in my ZZ> lifetime, so I asked.

ZZ> Thanks to anyone that can set my mind to rest on this annoying ZZ> subject. ZZ> JURB

... Chico of Borg: "Resistance? Atsa no good!"

Are we still hashing through this? Did I miss the post where it said "Check with the battery manufacturers" or "Check with someone who actually knows"? This myth is so pervasive that most battery manufacturers include it in their FAQ section. The universal statement? Storing on concrete does not increase the self-discharge rate of a battery, unless the battery is in a wooden case, ca. 1910.

Or just Google "lead-acid battery concrete discharge" for 38,000 hits on how this is not true.

Bill

"Bill Jeffrey" bravely wrote to "All" (29 Sep 05 20:09:45) --- on the heady topic of "Re: Old Husband's tale"

BJ> From: Bill Jeffrey BJ> Xref: core-easynews sci.electr > I had it explained to me that the difference in temperature

BJ> Are we still hashing through this?

I appologize to all for the sudden rash of replies. I don't know what happened but my replies over the past few weeks have been in a logjam and today suddenly they all got sent. Please, don't reply to any that are not relevant, thank you.

A*s*i*m*o*v

... If plugging it in doesn't help, turn it on.

Did your levee break?

"clifto" bravely wrote to "All" (30 Sep 05 12:55:43) --- on the heady topic of "Re: Old Husband's tale"

cl> From: clifto cl> Xref: core-easynews sci.electronics.repair:343677

cl> Asimov wrote: > I appologize to all for the sudden rash of replies. I don't know what > happened but my replies over the past few weeks have been in a logjam > and today suddenly they all got sent. Please, don't reply to any that > are not relevant, thank you.

cl> Did your levee break?

Thanks, looks like everything is back to normal again. (And... please, no comments from the peanut gallery. ;-)

A*s*i*m*o*v

... Techs would rather pee on an electric fence for the light show