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Re: [T3] Battery Question


On 5 Jul 2003 at 22:04, AdamVW wrote:

> t I did notice that the chamber
> nearest the negative terminal had cloudy, grayish (at least when viewed with
> my little flashlight) water in it.  I checked the voltage and found that it
> was just over 11 volts.  I jumped it again, drove it around for a bit longer
> this time, shut it off, and I was able to start it again.  More driving, I
> checked the voltage while it was running and I think it was about 11.5.  I
> turned it off and it went up 11.88 or so.  I recall that a post on this list
> said that a standing battery should be about 13 volts, and this is not.  I
> checked the Squareback, and it's battery is at about 13.1. 

A static battery voltage below 12V means that either the battery or the 
charging system have a problem. To find out which it is, you really have to 
test one or the other. The easiest test is to put the battery on a charger for 
awhile and see what the voltage does. A slow charge is much preferred; an amp 
overnight is ideal. 

If the battery voltage is still below 12V then it is dead. It probably has one 
cell open or shorted; either way it can't be fixed. It should be replaced.

If the voltage has come up above 12V then take it off the charger and let it 
sit for 24 hours. If it falls back below 12V then the battery is shot.

If the battery passes both of these tests, then the charging system is suspect 
and this is certainly a possibility.

> Is the cloudy-low voltage thing something that can be caused
> by heat?  I'm in Tucson, AZ, and it's been hitting well over 100 degrees
> here lately.  The engine has been fine, but I remember when I last bought a
> battery (last May or so) that the guy said the summers seem to kill them.  I
> think this is the first time I've topped off this battery, and I used
> bottled water (which may not have been ideal)

I don't know about hot weather. Batteries used in the tropics are sold with 
less concentrated sulfuric acid which reduces their storage capacity, but 
increases their lifetime. I don't know if such batteries are sold anywhere in 
the US. Probably not, because they would be more prone to freezing and most 
cars in the US face the possiblity of facing low temps at one time or another.

Distilled water is best, but anything will do in a pinch.

-- 
Jim Adney
jadney@vwtype3.org
Madison, WI 53711-3054
USA

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