Both my Chevy Sub and my GMC NAPCO are 225 miles away at my brother's house,
but I do
have my Chevy instrument cluster here with me and it has an ammeter (amps)
gauge in the
dash and not a voltmeter.
Does the GMC have a voltmeter or an ammeter?
Is this the orginal gauge or an aftermarket?
I couldn't quite tell from your description but I assume that it is hooked up
per the
shop manual.
An ammeter is a voltmeter with a current shunt built into it or on the back of
it. The
voltmeter measures the voltage drop across the current shunt and the meter
movement
(needle) is scaled to reflect current thru the shunt. The shunt that is part
of the
meter is designed to take that kind of current indefinitely.
The Chevy gauge has a built in shunt...ie, you can't modify it easily, but it
could be
done. I would assume that the GMC unit is similar.
However the main issue is that the approach that you are concerned about has
been normal
practice for much of the 20th century and has never been considered dangerous
or
unreasonable. As long as the wires are in good condition and the terminals are
clean
and tight, you should be fine.
Yes, some vehicles use a voltmeter instead and infer condition of the charging
system
from the voltage. The ammeter approach directly measures whether you're
charging or
discharging and by how much. Both approaches are widely used; neither is
considered to
have a notable safety advantage over the other.
Mark Noakes
58/56 Chevy Suburban
58 GMC NAPCO pickup
59 GMC Suburban
Knoxville, TN
SurfDudeSC@aol.com wrote
>
> So I'm rewiring my 57 GMC 1/2 ton and behold.
>
> Start solenoid (battery) -- to -- discharge side of voltmeter.
> Alternator primary -- to -- charge side of voltmeter.
> Ignition switch (battery terminal) -- to -- charge side of voltmeter.
>
> All 10 guage red primary wire with battery amperage running through one tiny
> little voltmeter in a steel dash in the cab waiting to short out and fry
> right before my eyes (or my 15 year old son's, see its his truck I just do
> all the mechanical work on it).
>
> THERE HAS TO BE A BETTER WAY!!! Any advice appreciated to get those amps
> outside of the cab where they belong. Thanks. David
>
> 57 GMC 1/2 ton, original 270 engine.
> oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
oletrucks is devoted to Chevy and GM trucks built between 1941 and 1959
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