Battery left on concrete floor

[Carlostrece]

We've all heard the urban legend that you should never leave a car battery sitting on concrete floor.

From my research, I know that was a legit taboo back when battery cases were glass lined wood boxes. Any crack in the glass (bumpy roads back then) would let battery acid slowly seep into the wood. Then setting the wooden battery case on the ground (or concrete floor) completed a weak circuit that would slowly drain the battery in 12-24 hours.

Later on (40s or 50s maybe) battery case were made of rubber. Rubber was a lot more durable than a glass lined wood case. However, when the rubber got old it would crack and then the same problems would occur. So you still shouldn't leave those old rubber battery case sitting on the ground (or concrete floor).

Battery cases have been made from plastic since the 70s or 80s. Modern plastic battery cases are tough and unlikely to crack or leak. So with a modern plastic battery case, it should (in theory) be fine to leave a car battery sitting on the ground or concrete floor.

Yet the myth or urban legend still persists to this day. Even many young guys born long after battery cases were made of plastic would never leave a car battery sitting on a concrete floor. Why?

In 2026, is there still a good reason not to leave a car battery sitting on a concrete floor? Or has it become a pointless superstition?

I bought a new 24F car battery yesterday. My neighbor left it on the concrete floor in my garage. It has a 1.5A trickle charger connected to it. It will sit there for a 3-10 days until my cousin has time to install it in my neighbor's 03 CRV.

The logical part of my mind is telling me it's fine for it to sit on concrete for 3-10 days because it's a modern battery with a plastic case. The emotional part of my mind is freaking out like I'm violating a religious taboo and a curse with consequences.

I know I'm probably nuts, but what do you guys think?

P.S. - I'm too physically handicapped to pick up the battery to set it on top of something like cardboard or a rubber floormat. I'd have to bother an able bodied neighbor, which I don't want to do unless there's a valid concern/reason to get the battery off the concrete.

 

[Lubener]

I bought a new 24F car battery yesterday. My neighbor left it on the concrete floor in my garage. It has a 1.5A trickle charger connected to it. It will sit there for a 3-10 days until my cousin has time to install it in my neighbor's 03 CRV.

It will be fine. I do it every winter with the six batteries from my tractor and riding mowers.

 

[ctechbob]

Pointless superstition.

There's nothing magic about concrete that would pull power out of a battery. It is probably because people put batteries on the concrete that are marginal in the first place and then never maintain them, and then magically when they go to use them they're dead. It wasn't the concrete, it was the mismanagement of the battery that killed it.

 

[joekingcorvette]

It doesn't hurt anything. I used to leave my boat batteries on a concrete floor but obtained a better storage unit now so I don't have to do that.

 

[Opelman]

I wouldn't worry the slightest bit especially with the charger attached.

 

[RDY4WAR]

This saying is a relic of circumstances made irrelevant many, many years ago. The old battery for my Camaro, before I converted it to 16v, was sitting on my shop floor for over 2 years. When the battery in my MIL's car died, which took the same battery size/style, I put that old battery in there. It fired right up and lasted her another 4 years.

 

[KGMtech]

The other myth is that you must use distilled water to top up batteries - if an option. I was told that by one of the oldest and busiest battery suppliers in town. Tap water is almost always just fine. Exceptions? Flint Michigan?

 

[kschachn]

The other myth is that you must use distilled water to top up batteries - if an option. I was told that by one of the oldest and busiest battery suppliers in town. Tap water is almost always just fine. Exceptions? Flint Michigan?

An exception would be anywhere with very high hardness. When I lived in the City of Milwaukee and we had Lake Michigan water, sure. But in the suburbs where well water is extremely hard, no way.

 

[Trav]

The other myth is that you must use distilled water to top up batteries - if an option. I was told that by one of the oldest and busiest battery suppliers in town. Tap water is almost always just fine. Exceptions? Flint Michigan?

Lots of places have very hard water, it will destroy a battery or cooling system, kettles and pots. So no not a myth.

 

[Donald]

We've all heard the urban legend that you should never leave a car battery sitting on concrete floor.

From my research, I know that was a legit taboo back when battery cases were glass lined wood boxes. Any crack in the glass (bumpy roads back then) would let battery acid slowly seep into the wood. Then setting the wooden battery case on the ground (or concrete floor) completed a weak circuit that would slowly drain the battery in 12-24 hours.

Later on (40s or 50s maybe) battery case were made of rubber. Rubber was a lot more durable than a glass lined wood case. However, when the rubber got old it would crack and then the same problems would occur. So you still shouldn't leave those old rubber battery case sitting on the ground (or concrete floor).

Battery cases have been made from plastic since the 70s or 80s. Modern plastic battery cases are tough and unlikely to crack or leak. So with a modern plastic battery case, it should (in theory) be fine to leave a car battery sitting on the ground or concrete floor.

Yet the myth or urban legend still persists to this day. Even many young guys born long after battery cases were made of plastic would never leave a car battery sitting on a concrete floor. Why?

In 2026, is there still a good reason not to leave a car battery sitting on a concrete floor? Or has it become a pointless superstition?

I bought a new 24F car battery yesterday. My neighbor left it on the concrete floor in my garage. It has a 1.5A trickle charger connected to it. It will sit there for a 3-10 days until my cousin has time to install it in my neighbor's 03 CRV.

The logical part of my mind is telling me it's fine for it to sit on concrete for 3-10 days because it's a modern battery with a plastic case. The emotional part of my mind is freaking out like I'm violating a religious taboo and a curse with consequences.

I know I'm probably nuts, but what do you guys think?

P.S. - I'm too physically handicapped to pick up the battery to set it on top of something like cardboard or a rubber floormat. I'd have to bother an able bodied neighbor, which I don't want to do unless there's a valid concern/reason to get the battery off the concrete.

I hope it's not a real trickle charger but rather a float charger or battery maintainer.

 

[Chris142]

My boss still believes in that nonsense. Makes me put wood under ever battery

 

[berniedd]

If your charger is not a smart trickle charger, 1.5 amps over 3 days will overcharge it.

 

[dogememe]

OMG yes I often encounter people who still believe that you can’t put a car battery on a concrete floor.

I have tried to politely reassure them it’s fine but 90% of the time they just argue so I’ve learned to stop wasting my energy on such people.

 

[ka9mnx]

The myth came around years ago when people put batteries in an unheated garage on the cold concrete floor. It's the cold concrete that affects the battery charge. Not the concrete itself.

 

[Carlostrece]

The other myth is that you must use distilled water to top up batteries - if an option. I was told that by one of the oldest and busiest battery suppliers in town. Tap water is almost always just fine. Exceptions? Flint Michigan?

Ya I'm skeptical about that. My tap water is hard city water. It has chlorine bleach, flouride, and a lot of calcium in it. Calcium builds up in my sink faucet, stains my sink, and builds up in my water heater. I'm not putting that in my battery.

When I lived in another city with cleaner tap water, I did use tap water because I was in high school because I didn't know any better. It didn't cause any short-term battery problems with a year or two, but I don't know if it might have affected long-term battery life.

 

[Carlostrece]

I hope it's not a real trickle charger but rather a float charger or battery maintainer.

Batteryminder 1500 is the model. $50 Amazon Prime.

It's a modern smart battery maintainer. I call it a trickle charger because it's max power output is only 1.5A. It goes into float when battery is charged. A pulsing float that (it claims) reduces/reverses/prevents sulfation.

Also, "trickle charger" is a colloquialism used in my local area to describe small battery maintainers with 2A or less max output. Everyone in my town calls them trickle chargers.

 

[Carlostrece]

My boss still believes in that nonsense. Makes me put wood under ever battery

Logically I knew it's nonsense because a modern battery has a plastic case, which does not leak. So it can't possible form a circuit sitting on concrete (like old fashioned batteries with leaky cases could).

Emotionally I was struggling with angst about violating the taboo. Mainly because my elderly neighbor man was giving me dire warnings. We share a communal condo garage. So he saw the battery on the concrete floor and freaked out. He was giving me dire warnings.

So then I started doubting my earlier decision to have it left on the concrete floor. Neither of us are fit enough to lift or move the battery. So on the floor it stayed. It's still on the concrete floor and will remain there until install. No more worries.

Every grandpa I ever met believes in that myth with certainty. I think it was probably a valid concern prior to 50 years ago. i.e. - prior to modern plastic battery cases.

 

[Donald]

Batteryminder 1500 is the model. $50 Amazon Prime.

It's a modern smart battery maintainer. I call it a trickle charger because it's max power output is only 1.5A. It goes into float when battery is charged. A pulsing float that (it claims) reduces/reverses/prevents sulfation.

Also, "trickle charger" is a colloquialism used in my local area to describe small battery maintainers with 2A or less max output. Everyone in my town calls them trickle chargers.

But a true trickle charger charges at 2A forever. You know at BITOG we over analyze every word!

 

[chainblu]

My boss still believes in that nonsense.

Many moons ago, I was an A&P Mech in Jacksonville. I was doing a scheduled battery replacement on a Dash 8, so I had the new batteries sitting on the hangar floor while I removed the old ones. They were Ni-Cad batteries with a metal case. One of my managers walked by and said - 'chainblu', you really shouldn't put a battery on concrete, it kills them. I let him walk away before I shook my head. This guy was a salaried manager.

 

[Carlostrece]

If your charger is not a smart trickle charger, 1.5 amps over 3 days will overcharge it.

It's a smart trickle charger. Batteryminder 1500