Lets talk about voltage.

[scirocco16vr32 at gmail.com (Chris Bennett)]

I would suspect a loose connection to the voltmeter.  I would get a
multimeter and check voltage across the battery before I made a call
on that.  You should see 12-14 volts if your alternator is charging
properly.  Turn off all the electrical stuff you can and see what it
shows.

In the alternator there is a diode bridge rectifier... these usually
work or they don't... not much in between.  I think if you lose one
diode it actually knocks two out of service and you get half as many
pulses (and it doesn't look like DC anymore.)  Not sure if this will
roughly half voltage or current.  I am thinking current.  Also with
the windings... they mostly work or don't.  (from my
experience...Please correct me if I am wrong.)

Point is if you have 14 volts give or take one, then I would look for
loose connections, corroded connections and/or grounds.

Remember Ohms Law.

HTH
Chris

On 11/7/05, Greg Pallett <greg.rocco@gmail.com> wrote:
> So after asking about 90a alternators, and not having come to any decision
> about that, I've been watching my volts gauge closely. I don't think I like
> what I see. In normal traffic I'm showing 12 volts. Last winter, after Roger
> relayed my headlights, it was more like 12+, but I don't remember how much
> over. Last night, running just headlights (no fogs) and radiator fan, I was
> showing 11. THis morning on the drive to work, I was showing 12 and was
> comfortable with that. This afternoon, stuck in early rush hour traffic,
> with the radio OFF and the only load being the radiator fan I was showing
> 11.5 or slightly less. I fear that in the dark of winter with highbeams and
> a heater fan on it may be too much draw. As I mentioned, I think last winter
> I had more volts to play with, but I don't remember any numbers.
> Could this be a sign of an alternator starting to get old?
> >Yes, I know I sholuld/need to check all my grounds, perhaps even add a
> fancy grounding kit?
>  Again, educate this fool.
>  TIA
>  Greg
>
> --
> Aronsons First Law
> People who do crazy things are not necessarily crazy
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