Can a battery be overcharged?

[Avalonjohn44]

I just started charging my battery, but will not be home tomorrow to unplug it (the manual says it takes about 12 hours to charge).  Is this bad?  Should I have someone stop by and do it, or should I wait until later to charge it?  

[Avalonjohn44]

Also, I read on another post that said I should not have the battery on a concrete floor.  Why is that?

[Ben]

Yes, it damages the battery to overcharge them.

No, other than leaving a white area on the floor if it boils some of the liquid out.  It should be washed from time to time with a little bakeing soda and water (with caps on) but I've never seen a plastic battery case that would conduct electricty if it was clean and dry.  That old wives tale about leaving a battery on concrete floor will disharge it is just that.

[abelfisher]

That old wives tale about leaving a battery on concrete floor will disharge it is just that.

This is not a wives tales!  You should not leave a battery on a concrete floor.  If you ever go look at stores that sell batteries, you will notice there are always a piece of wood beneath the battery.  I had a Mechanic tell me once NOT to leave a battery on a concrete floor.  This guy has been a mechanic all his life and I trust him.  I would not take the risk myself.

[Avalonjohn44]

If you ever go look at stores that sell batteries, you will notice there are always a piece of wood beneath the battery.

They're on a rack, just like everything else in the store...

Either way, I've put mine on a wooden bench.

[Low_Budget_Hooker]

WHAT??

never put a battery on concrete or any ground surface!  The battery is instantly grounded and will drain down to nothing.  It will drain low enough to damage cells.  You will never get as much charge into it as you could have before.  This has nothing to do with staibning the floor.  Personally, if your battery is boiling over and leaking water, you've got bigger problems.

[Ben]

This is one time I will just have to say, "To Each his Own". but tell me this, if that case conducted, what keeps the negative and positive post insulated and the battery from shorting between them, and it would have to be conduct to pass current to concrete floor. There are a lot of people that believe they will drain into a concrete floor. I was told the same thing most of my life until I started making a living messing with them, but it just what I said, An old wives tail. Remember, I said a clean, dry battery and that a battery should be washed with baking soda from time to time. Yea, you see them sitting on wood pallets, that's for the ease of moving them around. How many places you see with them on metal racks, bolted or sitting on concrete floors, but guess that metal is not conductive.

The only batteries that need to be stored on wood is the big industrail batteries built into a metal case. Because of lack of proper maintenance they can start conducting to the case.

A wood board or scrap of plywood is cheap, and if you think it has to be on one to charge it or store it, put it on one, I don't waste the time and haven't for many years.

Oh, thought I would add this link from US battery on care and maintenance of their batteries, strange they don't mention they must be on wood.

http://www.usbattery.com/pages/usbspecs.htm

[cart7t]

This is one time I will just have to say, "To Each his Own".  but tell me this, if that case conducted, what keeps the negative and positive post insulated and the battery from shorting between them, and it would have to be conduct to pass current to concrete floor.  There are a lot of people that believe they will drain into a concrete floor.  I was told the same thing most of my life until I started making a living messing with them, but it just what I said, An old wives tail.   Remember, I said a clean, dry battery and that a battery should be washed with baking soda from time to time.   Yea, you see them sitting on wood pallets, that's for the ease of moving them around.  How many places you see with them on metal racks, bolted or sitting on concrete floors, but guess that metal is not conductive.

The only batteries that need to be stored on wood is the big industrail batteries built into a metal case.  Because of lack of proper maintenance they can start conducting to the case.

A wood board or scrap of plywood is cheap, and if you think it has to be on one to charge it or store it, put it on one, I don't waste the time and haven't for many years.

Oh, thought I would add this link from US battery on care and maintenance of their batteries, strange they don't mention they must be on wood.

http://www.usbattery.com/pages/usbspecs.htm

You are correct. It's an old wives tale and your reasons are valid. The plastic case acts as an insulator. If the plastic case was actually conductive, you lose more charge between the positive and negative posts than you would into concrete.  Besides,  for a battery to discharge through a plastic battery case into the concrete would require there to be some sort of conductive path from the positive terminal on the battery to the negative that caused it to conduct.

I pull my batteries every winter and store them in the garage on a concrete floor. They've never discharged.  Old wives tale.  

[redboat]

WHAT??

never put a battery on concrete or any ground surface! The battery is instantly grounded and will drain down to nothing. It will drain low enough to damage cells. You will never get as much charge into it as you could have before. This has nothing to do with staibning the floor. Personally, if your battery is boiling over and leaking water, you've got bigger problems.

I was the one who, in another thread, said not to put the battery on the garage (or other concrete) floor. Has nothing to do with discharging it: The floor's cold, will conduct same to the battery.

[Ben]

Just so you can get it from the horses mouth (not that Mr Wehmeyer is a horse) I talked to Mr Fred Wehmeyer, the engineer at US Battery and ask him if he would mind posting on this site. Hopefully he will get time and I gave him the right address.

[Low_Budget_Hooker]

Yup, After some more reading and a quick email to optima battery, I stand corrected.

A battery "go-to" member would be a great idea. Lots of confusion about batteries and on many different levels,

Charging

over-charging

maintenence

24v vs 12v

on board chargers

wiring in series or parallel

etc

Techniology is also an added source of confusion with the spiral, or gell cell batt's becoming so popular.

Hopefully, he would be a willing member, sounds like a great resource.

So yea, thanks Ben and Avalon, I stand corrected, or as I like to put it,..."re-educated"

[FredWehmeyer]

As indicated, I was asked to weigh-in on the battery-on-concrete' issue and other battery related issues. For credibility sake, I've been designing, manufacturing, and testing all types of batteries for over 30 years. I've often been asked about storing batteries on concrete floors and the best way to answer is No it's not an old wives' tale because Old Wives' Tales don't have any basis in fact.' Not storing batteries on concrete does have some historical basis, it just doesn't apply to modern batteries. In the old days' (>30-40 years ago) batteries were built in fragile wooden, glass, or brittle hard rubber containers that often cracked and leaked electrolyte (sulfuric acid). The acid would not only damage concrete floors but could also cause a short circuit if it electrically connected two or more cells externally thru the electrolyte. This could cause the battery to discharge during storage. To offset this tendency, battery gurus developed the concept of placing wood or other absorbent insulators under the batteries to absorb the acid and insulate them from the floor and from themselves. Modern battery containers are now made from tough polymeric materials like polypropylene that resist cracks and abrasions and seldom leak. However, if you plan to place a battery on a surface that could be damaged by acid, I recommend putting an absorbent insulator (wood, plastic, newspaper, etc.) under it. I once knew an unfortunate battery salesman who was making a final presentation for a lucrative contract to a large retailer. He had placed a live, prototype battery in the middle of the retailer exec's mahogany desk for discussion purposes and after negotiating the contract, picked it up to leave. It left a noticeable acid footprint in the mahogany. He got two orders: Get Out and Stay Out!'

I did notice one interesting comment about the effect of concrete on lowering the battery temperature. This would have a positive effect on storage since batteries self-discharge more slowly at lower temperature (battery self-discharge rate doubles for 10'C or 18'F increase in battery temperature). Batteries should always be fully charged prior to storage and deep cycle batteries should be recharged every 2-3 months during storage for best life.

Regarding the question of overcharge damaging batteries, the answer is yes. Extended overcharging can lead to over-heating and water loss reducing performance and life. If the charger does not have an automatic turn-off or turn-down (float) mode, an easy way to prevent inadvertent overcharge is to use a simple wall timer set for 12 hour max time.

Hope I've been able to help,

Fred Wehmeyer

Director of Product Engineering

U. S. Battery Manufacturing Company

Augusta, GA 30907

[Ben]

LBH, One suggestion, if ya'll would add the link to US Battery to this site, they do a great job at answering a lot of the basic battery questions that get asked if they take the time to go through and read it. They have an excellent chart on battery run time per size battery versus amp draw also. It uses their battery numbers but works for any battery for equal Ah capacity.

Mr. Wehmeyer, quess I was typing while you were posting and didn't see it.

Glad you found the site and joined in. Hope you will become a regular visitor and keep things straight with batteries and charging them. There's alway's mixed opinions on how one should be maintained and how/when it should be charged, and what's the best type charger to use. I get myself between a rock and a hardspot a lot of times because I have a tendency to be more than a little specific on my point of view. I've just messed with them for more than a few years, know a lot about them but by no means an engineer, your point of view would have a lot more credit.

[Team_Dougherty]

Here is a great resource about batteries

http://www.uuhome.de/william.darden/

Paul

[paparock]

I don't know the technical facts but I do know that when I left two deep cycle batteries on the concrete floor of my garage connected to an automatic battery charger that monitors battery charge adding charging only when needed they were totally useless when I went to use them. :-/

[Ben]

I GIVE UP!!!,

Ya'll win.  I'm the dummy and just forgot everything I ever knew about batteries so don't never sit a battery on a concrete floor, it will kill them dead, make total junk out of them.  God, how lucky I've been it's never gotten the untold numbers I've left on the floor over the years.   It's seems to be a proven fact the charger, battery condition, stratification, sulphation or any of those things could possibly have anything to do with the battery going bad sitting on concrete.  Like a said, wood is cheap.

OH! and yes,  I very much have a tendency to be a (call me what you like) when I get frustrated, but ya'll can relax, from now on I'll leave the batteries to the experts.

[abelfisher]

Well I guess I stand corrected as well!   Or as LBH says, "re-educated"..  Makes sense what Fred Wehmeyer said.

Great thread of information!

Thanks!

[flechero]

Mr. Wehmeyer,

Thank you for taking the time to post here.  Your expertise and input is greatly appreciated!  Hope you check in from time to time and clear some of the battery questions up.

Ben,

A thanks to you for asking Mr. Wehmeyer to jump in here.  He validated everything you said.

-keith

[Low_Budget_Hooker]

Ben,..no need for angst,lol.  

You've helped us out here, at least me anyway.  Fred also answered a couple other questions through PM's for me.

I appreciate the effort and the new resource.

[MyKeyBe]

Ben,

Relax, man. You where right. Just give em one of these and call it a day.

Paparock,

Your charger is F'd. CONCRETE WILL NOT KILL A BATTERY.

Think about it. We put batteries in aluminum boats (on bare aluminum) and put the boats in water. I will bet $100.00 that aluminum conducts electricity better than concrete. Much better.

Corrosion, small leads, bad terminals, poor grounds, shorts, etc... will kill a battery. The floor will not.