From: kludge@panix.com
Tom Del Rosso wrote:
>Mark Olson wrote:
>> Tom Del Rosso wrote:
>>> The shop will have to start it again, so how long before that damages
>>> the battery or something?
>>
>> Why would they _have_ to start it up?
>
>I would expect any shop to look and see for themselves before believing
>the owner.
You need to find a real auto electrical shop.
>> I would remove the alternator, and test it on a bench setup
>> with a known good battery, both without load (except the fully
>> charged battery) and under some load. No need to start the car and
>> potentially damage lots of expensive electronics from overvoltage. If
>> the alternator tests bad, probably the internal regulator needs to
>> be replaced. If it tests good, I'd look to the wiring in the car,
>> especially ground straps/braids.
>
>Is it common for a shop to have a setup that can spin up an alternator?
Yes. Any auto electrical shop will have a test rig for alternators and
starters.
>> I would also question the health of the battery, I'm surprised that
>> the alternator was able to overdrive it to more than 19V.
>
>Should I tell them to replace it anyway?
The battery? No, but I'd definitely check the level. If it has been run
overvoltage for a while, the fluid will be way low. And remember, if you
are seeing 19V at the buss, and the battery is trying to pull down the
voltage to 14V or so, then you likely have well over 20V coming out of the
alternator.
Pull the regulator, check for shorted SCRs. If the board has been rebuilt
with cheap substandard parts, it'll be evident when you have it out on the
bench. If that's the case, check the bushings and brushes too to make sure
that they are of reasonable quality.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
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* Origin: you cannot sedate... all the things you hate (1:229/2)
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