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Larry

Larryr wrote in news:422276b1-0f4b-4462-8db5-
:

The panel meter is .2-.3Volts low and is quite upsetting when it says
my 900AH golf cart bank is at 12.0 when It's in the high 12.3 with a
10 amp draw....

If you would remove the panel meter and take it to a calibration shop that
does analog meters, they will put it in a magnet charger and put an
accurate full scale voltage on it. Then, they will pulse the magnet
charger to bring the meter's permanent magnet up to proper magnetic field,
making the meter read correctly. They will track the meter and if the
tracking from full scale to zero is out of tolerance, they can rescale the
meter scale to read correctly....for more money, of course.

If you tell them you want the meter to be dead accurate at some point on
its scale, say 14.2V for accurate charging, they can calibrate the magnetic
field at that point, instead of full scale.

They'll also test the D'Arsonval's movement jewelled bearings and set the
tension on them, which will have slackened over its lifetime, and make sure
it has the right hairspring tension for good tracking. The hairsprings
slacken tension over their lives, making the meter too sensitive and
spreading the scale inaccurately.

Sure is cheaper than a new, also inaccurately calibrated, meter.

If you're near Houston or Virginia Beach find EIL Instruments and give them
a call. I used to be their mobile calibration van manager, dragging an
office trailer across the country repairing and calibrating CG and FAA test
equipment, on site. Both places had meter calibration facilities to
support commercial and military shipping panel meters, which are still in
use today.