[Public-List] A4 alternators

[Janet Kirk]

Gord... I'd be more suspicious of the batteries than the alternator, but it 
pays to check each, preferably at a battery or auto electric shop where 
they have the test equip. Just an open voltage measurement doesn't mean 
anything. A shop will have a battery tester which is just a humongous 
rheostat that puts a 200-300 amp draw on the battery for a several seconds 
and observes the voltage drop. Using that, along with a hygrometer, is the 
most reliable battery health check.

A cute alternative if you don't have a big 500 amp carbon pile battery 
tester in your tool box and don't feel like hauling the batteries to the 
shop, is to hook up one or two 100 watt desk lamps to the battery via an 
inverter*, and time how long it takes to run the battery down. That will 
give you a good amp-hour capacity to compare with the battery's spec. A 200 
watt draw on a 12V battery is 16 amps so should give 6 hours on a full 
charged 100AH battery. (Do it on deep-discharge batteries, only.)

Bob Kirk
Isobar #181

* It's more convenient to interpret if you put it in series with one of 
those neat little Kill-A-Watt household watt-hour meters which are becoming 
popular. Every home should have one.

At 07:05 PM 7/26/2009, Gordon Laco wrote:
>John - do you know what indicators I should look for to determine if my
>batt's are shot?
>
>Gord
>
>
>  On 7/26/09 7:01 PM, "Gordon Laco" <mainstay at csolve.net> wrote:
>
> > That may be it... My batteries are quite old and got submerged in the 
> spring
> > due to an improperly adjusted stuffing box.
> >
> > Damn - did it admit that I did that?
> >


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