Dry dead battery

How far do you have to walk with your new battery?

Tom

new battery? what do you mean?

rK

Depends on the tap (or well!) water. Wells and some mains water here can have some iron salts in it which can be deadly for lead acid batteries. Sounds like it 'boiled dry'! You may, by adding water, get some capacity back but I wouldn't guarantee it. Too many amps for too long a time, maybe? Someone more expert could comment on this; but isn'tan automatic charger supposed to stop when the battery potential has risen above a certain value, maybe for a certain period of time. If the battery is dry ............... ergo no potential! Therefore no automaticity?

I assume that this is a car battery of some kind where you can open up the holes and look inside? It might have been dry or close to it before you started charging and you should have looked before starting the charging cycle on it.

And yes, you do want to add _distilled_ water. I gather you don't want to walk to the store just to drag back a gallon of it if there is another option.

"Automatic" chargers doesn't mean much, except that they are supposed to be easy to use -- which says little about their quality as a charger or what they might do when faced with a battery that isn't in reasonable condition to start with.

Water under the bridge, though. You are now faced with a dead battery that is basically dry inside and has been attached to a charger for a weekend of charging which was started, apparently, without the battery being in good condition to start or else where the charger itself may have damaged the battery (or some combo of those.) In other words, the battery's condition itself is in serious question now and there is no certainty that distilled water will restore it. I also gather that this is the car battery for your only transporation means, which is why you need to walk to the store.

Normally, fresh lead acid batteries have nice clean lead plates with a solution of H2SO4 (sulfuric acid, which is a thickish liquid in pure form at standard temperature and pressure) and H2O (water.) I recall vaguely that H2SO4 boils around 300C, or so. H20 at 100C, obviously. So if you boiled off the water with the charger, it might leave the H2SO4 still inside the battery. If that were the case, and assuming that the lead plates themselves weren't shorting out each other by way of poor regrowth, you might be able to recover your battery by adding distilled water to it. But you seem to say that it is _dry_, and this implies to me that you might also have boiled away the H2SO4, as well. In that case, I'm not sure what to suggest. In the best of cases then, you'd still need a supply of H2SO4 as well as the distilled water. Which means just getting some water won't help a lot.

I'd probably just get some tap water, let it sit in the open for a few hours to allow some of the added chlorine (or not, your choice) to leave, and then use that in your battery and just plan on replacing it, if you are lucky enough to get it working at all. Either way, I think you are facing replacing your current battery, though. It's probably not wise for your only source of transportation to be depending on a battery that has been through this kind of trauma.

Jon

I mean you need a new one. You most likely fried the battery. If the plates are warped or other damage typical of cooking dry you will not be able to save this battery. Sure, you can try, the odds are low. That's why I asked if you wanted to walk twice. If you have any good beer in you fridge, tell a neighbor he can have a few cold ones if he would give you a ride to your new battery. Sorry for the levity, well not really.

Good Luck, Tom

It's my motorcycle battery and it's the situation where I need it to get to this job so I can afford to fix it. I just came off disability and with $4 to my name I spent $2 on a gallon of distilled water...

So I am going to try it and see what happens. I will post my results....

Isn't H2SO4 a solid? I don't know - I'm thinking of, like, NaOH which dissolves in water to make the base. I'll ask on sci.chem and see...

Here goes...

Okay. It sounded like that kind of situation. I've been there in my life, too, so I can feel your pain.

If there doesn't appear to be _any_ sulfuric acid inside, then I don't hold out much hope here. But best luck, anyway.

NaOH is a solid. White, and kind of slippery to the touch. But sulfuric acid is a liquid. I've used it, before, as part of a double boiler situation that could achieve the higher melting points I needed at the time while also providing very, very even heating which was also necessary for the rocket fuel I was making then.

Jon

Suppose a cell was shorted - battery V wouldn't rise high enough for the automatic charger to shut off.

Ed

Depending on local weather conditions, rain water should woek as well.

Battery now works!!! I put distilled water into my dry, dead battery, then I charged it, and it cranks beautifully and started my motorcycle!!!

The conducty thingies (anodes and cathodes?) don't go all the way down so I think I boiled the water down to that level at which point the contact was broken and the overcharging stopped. This is my hypothesis. The H2SO4 didn't go anywhere because it was below that level and has a much higher boiling point than water.

I was asking guys over at the motorcycle group and they were saying that a lot of battery chargers are too powerful for motorcycle batteries. Thanks for the help!!

rK

Huh? But you said it was dry (i.e. not wet) and I believe the definition of the word isn't specific to H2O alone.

Surely if you were aware of acid sloshing about at the bottom of the case you wouldn't have used the word 'dry'!?

Chris

uh. no sloshing, and i didn't turn it upside down. It seemed pretty dry. I moved it side to side briskly and neither felt nor heard anything "slosh". But how else would this be explained? Is H2SO4 pretty viscous?

rK

a bit oily.

I wonder what substance they use in jelly-electrolyte lead-acid cells ... to suspend the acid in a jelly.

Chris

Rain water is not clean. It has a nucleus of something and collects crap on the way down.

Tom