Myth - Batteries Discharge on Concrete

Mark Manager Sahuarita, Arizona Posted   Latest  

Myth - Car batteries Discharge on Concrete - battery must be charged and stored on a wood board.

Come on...really. Batteries back in the day sat on a steel plate in the car. How do the electrons make their way thru plastic or the old rubber based battery cases?

Speculation on source - Battery charge and power delivery are very dependent on temperature. In colder climates, sitting on cold concrete would compromise charging and power delivery efficiency.

Zero time to figure this on out. But techs I worked with were absolutely convinced this was true. When questioned about how this was technically possible; they had no explanation.

I wonder if this myth still is out there.

Mark …

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Rick Diagnostician
The Woodlands, Texas
Rick
 

Mark, Car batteries used to be encased in hard rubber, a substance that was porous enough that battery acid could seep through it and create a conductive path through the damp concrete, draining the battery. The "myth" is actually the truth from another era/battery design. snopes​.​com/fact-check/bat… HTH

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Chris Diagnostician
Commack, New York
Chris
 

Yes this used to be true, but the myth still persists today. It was "taught" to me when I first started 20 years ago. It was treated like gospel, all batteries were on the battery rack, on wooden blocks.

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Mark Manager
Sahuarita, Arizona
Mark
 

I have a great deal of respect for snopes. But I still don't get it. Is the concrete floor a low level short..,to ground? Between the plates? The electrolyte is always between the plates. Why doesn't the metal plate the battery is mounted on in the car do the same? Technically how does this work? Where is the current path?

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Tanner Instructor
Wellford, South Carolina
Tanner
   

Something that I have always wondered and unfortunately never had an answer to is can condensation form inside a battery? I can tell you after having most of my property in a storage unit for the last two years that condensation can form inside plastic totes. I would assume sitting on a cold concrete slab could cause this to happen more frequently. If condensation was able to form inside a

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Chris Diagnostician
Commack, New York
Chris
 

Where would the condensate come from? wouldn't the humidity level already be high in the battery? I would like to think that even though vented, the "airflow" would be low, and the condensate would be from the acid/water mix. If anything the humidity from inside the battery would exit from the battery faster than humidity would get in. Well, unless the battery is underwater. I honestly don't

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Tanner Instructor
Wellford, South Carolina
Tanner
 

Because the battery is full of water that would make it more prone to condensation. It would basically be the same as a plastic bottle getting condensation inside it. The low airflow inside a battery would also make it more likely as the more airflow you have the less likely condensation is to form, the less airflow the more likely. Also humidity may not exit the battery if the dew point is

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Mike Instructor
Fresno, California
Mike
 

It is. More prevalent among people our age.

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Jim Mobile Technician
Southampton, Pennsylvania
Jim
 

I don't know about that, I've been told by A LOT of techs that MARK WARREN taught them that one night in a bar ??? So it must be true. LMAO

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Thomas Technician
Manassas Park, Virginia
Thomas
 

Im with you on this one mark. I was told that since concrete is colder than the battery itself the temperature is what drains it. To that I say what is the difference of a battery that sits on a metal hold down plate in a car when the outside temp is below 32 degrees?

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Jim Curriculum Developer
Frederick, Maryland
Jim
 

Can a battery with dirt and moisture across the top discharge faster than a clean battery?

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Mark Manager
Sahuarita, Arizona
Mark
 

Jim - not sure about dirt and moisture. But you can measure the voltage draining across the top of a battery with electrolyte spewed on top.

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Jim Curriculum Developer
Frederick, Maryland
Jim
 

Agreed. Then if early case designs were semi-porous this can happen on the bottom of the battery, especially depending on what it is sitting upon. That was how this was explained to me during the tour of a battery manufacturing plant with a product engineer when someone asked the question. Modern materials and tech have eliminated the potential. (HA! Electrical joke!) ;)

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Mark Manager
Sahuarita, Arizona
Mark
 

The voltage I have measured on top of the battery travels from the negative to positive post thru the electrolyte connection. Not sure I buy the porous rubber case theory. But let's assume it is true. What is the current path? Post to Post? Like on the top? If it is thru the bottom, placed on concrete, how is this a better conductor than the metal plate it is mounted on in the car? If it is

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Rick Diagnostician
The Woodlands, Texas
Rick
 

Mark, Here another explanation that may shed some light. homepower​.​com/articles/solar… HTH

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Mark Engineer
La Junta, Colorado
Mark
   

Mark I spent decades as an automotive research engineer. Through the years I was able to be in the same room with some extremely intelligent and knowledgeable men and women (not always other engineers). I remember being told (by a battery engineer) that his dad (or relative) worked in the military procurement area (huge warehouses and stockrooms). Evidently, back in or around the second World

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Alvin Mobile Technician
Beaumont, Texas
Alvin
   

Early batteries had wooden cases covered in asphalt and would definitely leak voltage. This was improved with the hard rubber cases and then fixed with the modern plastic cases. it is amazing how these OLD WIVES TALES live on

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