Gauge panel as per the pic - car has a 12 volt conversion with voltage reducers on the gauges. My electrician is uncertain re wiring up the amp meter to get it to work correctly ? Anyone with an electrical background that could draw out a wiring diagram. Gauge panel is 46-48 Ford (Australia and New Zealand) I think its maybe 41-42 Ford USA ? note: My auto electrician is very new to this "old car' stuff............
Inductive meter I believe. Just lay the wire through the little “prongs”. Can you take a pic of the rear of the panel to confirm?
The ammeter goes "in-series" between the battery and ignition switch [the starter motor has a separate feed] The Alt/Gen charge wire goes to the Ign side of the ammeter. They are not voltage sensitive ,and if the ammeter reads the wrong way simply switch the polarity.
With that gauge his answer is the correct answer. An ammeter just shows which direction the current is flowing and how much current is flowing at the time. It is either going towards the battery or away from the battery.
If reading the wrong way, you just run the wire in the opposite direction. One has to leave enough loop in it though, don’t ask me how I know