Ron, you are a gentleman and a scholar! It would be hard to find anyone these days under 70 who has not been brainwashed and understands why an ammeter provides more useful information. After the 1950s they started using voltmeters because it was a lot cheaper. You could actually avoid running heavy wires to the dash using a shunt and milliammeter, but that's also expensive. I've run the wires and installed ammeters on most of my vehicles. Even the smallest, cheapest ammeter will tell you if the alternator is charging or not.

A voltmeter has to be very precise and accurate and you need to memorize the exact voltages that would indicate what's happening. Voltmeters in cars don't read in 1/10ths of volts and are of dubious accuracy.
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1992 745, >500k km