Top of Battery Wet: Cause for Concern?
 

A couple of weeks ago, I topped off the battery cells (Mercedes battery, 4-1/2 years old) with distilled water. It is POSSIBLE that I slightly (though not by much) overfilled some of the cells, but I'm usually pretty careful about such things. The caps were definitely properly tightened.

This morning I noticed that the top of the battery was wet. If I overfilled slightly, would this force the water out and account for the wetness? Or does it sound like I have a leaking battery? And if the latter, how critical is it that I replace the battery?

Thanks.

I'd remove any excess water with a turkey baster if your level is too high.

Sprinkle baking soda on the wetness to neutralize the acid.... let it sit a day, wipe it off.


Same goes for anything else that got wet in the area.

Well. it really can't "leak" out of the top. I would say it is overfilled and active charging will force the level up a little, (I think).

x2

Make sure your alternator is not seriously overcharging the battery. This is done by measuring the voltage at the battery with the engine running. The battery fluid could have been low from boiling it off with any overcharge.

Somewhere around 13.5-14 volts is what you are looking for. More and you need a new voltage regulator in the alternator. A self changeable part.

It's also worth putting a voltmeter on the battery to make sure you're not overcharging which will cause the battery to boil.
I've always mixed my baking soda in water and poured it over the battery to clean off any acid. Is that a bad idea? Is it better to sprinkle dry soda on it?

Ooops, looks like Barry and I were breathing the same ether at the same time at different ends of the continent.

Wetness can be caused by over charging. Check the voltage at the battery with engine around 2000 rpm and all accessories and lights off. If the voltage is above 14.7 or so, replace the voltage regulator. The battery itself can also cause this problem. Actuallly the amperage of the alternator needs to be checked also but this requires equipment most DIYers dont have and most Autozone type places dont understand. If the water was down and that is why you needed to add some wwater, than there is something wrong. Be careful working around a battery that is subjected to over charging as they give off hygrogen(sp) gas that can blow up.

Paul

While we're talking about my battery....I've also got "acid cake" (I'm sure there's a better term for it) building up on one of the terminals. I neutralize it, then it comes back. So that indicates a leak, right?

Smear petroleum jelly on the terminal after you've brushed it clean.

yeah, this will cut down on the formation of the crud, but does not address the cause of it.
be sure and check your alternator for overcharging, and if the cable has serious crud infection, it should be replaced.

May not be true, but we've always associated crud forming on the cables with "older" batteries that are usually within two winters or so of failing.

yup.
crud formation is from acid fumes collecting on the positive terminal. then the lead breaks down and forms that crud. good batteries do not do this. good alternators keep good batteries from doing this.

When I had a Sears International DieHard have the white powdery stuff at the positive terminal build up, I replaced the battery in 2009. It was in use since 2001.

Alternator was replaced in 2006 I think, with 65A.

Cleaned the terminal and cable, no more build up. But there are some residuals in the small holes on the cable terminal surface, maybe I need to dunk it in some Coke.

I had AAA come out. Battery and charging system all check out fine.