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MG MGA - Battery Fluid

I know this seems like a strange question but here goes. I have always added distilled water to batteries when they get low. I just replaced my batteries with new ones. Of course they were full of acid when I installed them but the time will come when I have to add fluid. Someone, the battery dealer, just told me to add acid not distilled water when needed. Any thoughts?
Joe Wiley

Find another battery dealer!
Charging evaporates water, but the acid stays in the battery, thereby becoming more concentrated.That's called fractional distillation. So you add water as makeup. The only time you add acid is if it has been spilled, or a hole punched in the case. In that case, you need to check acid concentrations and adjust as needed. I'd bet there are maybe 3 people in the country who actually still know how to do this. Old British manuals used to tell you how, but I've never spilled a battery in my life, though I have patched a few and added acid - by "feel" rather than science.

FRM
FR Millmore

I can't remember when I last topped up a battery. they all seem not to require it these days. How's it done?
Art Pearse

Technology has resulted in much less "gassing" and water loss. Some batteries are now sealed, so you cannot add water; if you need to, then something is very wrong. This is sort of like "lubricated for life" - when the water (or lube) is gone, the thing is dead.

Most batteries I see can be checked and topped off just like they used to be, but you have to pry the lids off instead of unscrewing them. Sometimes annoying, but it does lessen the chance of people filling them with antifreeze, washer fluid, brake fluid, oil, etc - all of which I have seen. And the caps are rarely missing now, which was not always true.

FRM
FR Millmore

On the older style batteries there are screw caps on each cell. When removed you can see the acid level. Do not use tap water, use de-ionised or distilled water. The level should be maintained so that it does not drop below the top of the plates. The manual says just above, but I like to have about 1/4" or so.

Some of the newer batteries have pull off plastic caps covering three cells, but the principal is the same. More common now are sealed for life batteries.

Note that when you start fiddling with batteries/caps it is very easy to get tiny splashes of acid. These often go unnoticed unless they hit you in the eye! They also have a knack of leaving holes in your clothes that only become apparent after washing! Don't ask...
N McGurk

Topping off batteries with distilled water is still done in general aviation. But it's becoming increasingly less common even there.
Del Rawlins

Sealed batteries were the bane of my grandfather's existence when my grandparents had a winter place in Palm Springs. He got very adept at modifying them so he could add water and save the hassle of trading them in every fall. Even sealed batteries lose water in 110 degree heat.

David Breneman

Back in the day, We used to flush out dead batteries to recharge them. We would dump the acid, fill with a Baking soda and water mix and flush a few times with water. Then we would add new acid. Generally the battery would give us a few more years.
Mike Parker

This thread was discussed between 13/06/2012 and 14/06/2012

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