There's a nice write up here at
MGA Gurus about the two different conventions and why things eventually converged on negative grounding.
That's a good explanation, thanks for posting that link.
That with your description of the alternator having the ability to switch off when fully charged, make all of that part make sense to me. In a way an ammeter is kind of a geeky thing, to know exactly what is flowing through the wires. Where with a voltmeter you would see constant voltage on the circuit. Hmmm...Most modern vehicles don't seem to have either ammeters or voltmeters...AFAIK.
