I Over Filled My Battery, Now What?

[ridewv]

So when topping off my battery I over filled three cells, almost up to where the white case meets the black top. So the electrolyte is too diluted isn't it? If I just remove the excess wouldn't doing so correct the level but leave the liquid still over diluted? Does it even matter? I don't want is to leave it that high though.

Thanks,
Rick

[lkchris]

Don't think you'll have much problem and you're correct in not leaving it overfilled.

[Rbike]

Just save what you take out to feed to your neighbors cat...you didn't cause any problems, it'll charge up just fine with use.

[Boxerkuh]

I think you are on the money. Mistake made, mistake learned. I would pull the extra water out and maybe save it. Once the level is correct, put a trickle charger on it and watch it. Keep the extra fluid for future need.
For that reason I went to Dry Cell Battery. I have had mine for two years without any problems. I put a trickle on it twice a week, which is probably an overkill. I am planning on keeping it at least another year, if not two. I that Oak does not like Dry Cell Batteries, due to the history of them giving out without a sign... but so far I am good. I guess I am running kind of an "unoffical" test to see how it works... but dry cell batteries are "hassle free" and idiot proof (which I need!! :laugh )

[pmdave]

When your battery was filled originally it was filled with an acid/water solution. The acid doesn't evaporate, but the water in the acid does evaporate, leaving a somewhat more concentrated acid in the cells. (assuming the battery doesn't burp out acid from the overflow tube)

When you fill the cells, you're just adding water (I trust you understand the need for pure water) to the acid to get it back to it's intended dilution.

If you overfill the cells, you're diluting the acid slightly. If you remove some electrolyte from the overfilled cells, you're removing some acid. You can't remove just the water once it's mixed with the acid. Theoretically, you could save the electrolyte and use it to refill the cells at some future date, but that's impractical. You could test the specific gravity of the electrolyte at some future date.

Water evaporates (from a typical lead acid vented battery) via the vent hose, due to hot conditions, and also by a battery heated by excessive charging. So, if your battery is using a lot of water, it would pay to do some electrical system checks. I've also had battery cases get cracks in the sides from exposure to sunlight, and actually leak acid down the sides (of the end cells)

Boxerhuh refers to "dry cell batteries". I'm assuming you mean "maintenance free", as in AGM, or in "gel" batteries. AGM are lead acid, but have high zoot separators that soak up and hold the electrolyte so it no longer needs to vent to the outside. Gel batteries are different. In general, you can use the same maintenance charger on a vented lead/acid as on an AGM, but a gel battery (as on some late model BMWs) requires a charger with different characteristics.

Rbike's snide comment about cats is out of place on this site, and I would urge the forum administrators to not tolerate it. If you need me to explain this in more detail, I could oblige.

pmdave

[ridewv]

I'd like to thank everyone for the advice, even Rbike :cat I will take your collective advice and remove enough to the level down to the "max" line. I don't want to install it overfilled.
When I had removed it I found the positive terminal and wiring lead with a lot of slimey green corrosion, three cells low, and noticed there was a slight mashed area in the bottom edge of the battery itself. The battery does seem to charge OK with my Optimate 3 charger so I believe it's OK. I used lots of baking soda and water to clean up the wires and terminals which I think are OK now. Dumb question now... how difficult is it to replace the positive lead? I see it goes back under the tank, but how much connecting etc. is involved? If it isn't too hard maybe I should replace it too. Thanks again!
Rick

[cjack]

I'd like to thank everyone for the advice, even Rbike :cat I will take your collective advice and remove enough to the level down to the "max" line. I don't want to install it overfilled.
When I had removed it I found the positive terminal and wiring lead with a lot of slimey green corrosion, three cells low, and noticed there was a slight mashed area in the bottom edge of the battery itself. The battery does seem to charge OK with my Optimate 3 charger so I believe it's OK. I used lots of baking soda and water to clean up the wires and terminals which I think are OK now. Dumb question now... how difficult is it to replace the positive lead? I see it goes back under the tank, but how much connecting etc. is involved? If it isn't too hard maybe I should replace it too. Thanks again!
Rick

It's not easy to change the terminal lug for most people. It's part of the wiring harness. I would just clean it very well, clean the acid out of any craters on the metal and grease if up well. If it is not too thin...mostly a mechanical issue.

[ridewv]

It's not easy to change the terminal lug for most people. It's part of the wiring harness.

Thanks Jack. I'll strip back the insulation a couple inches and clean thoroughly. When I was soaking the wire in a baking soda solution, there was a lot of foaming coming out from under the insulation so I feel the acid has worked it's way in a ways. The wire seems like it's ok.

Rick