In message , "Dave Plowman (News)"
writes

It also depends on what is wired via your ammeter. It will obviously show
charge, but not everything on the car might be wired through it to show
discharge.

The main connection from the battery goes to the starter switch. From
there (same side of the switch), a brown wire goes to the A terminal of
the Control Box. The idea is to break that brown wire for the ammeter,
so the ammeter reads everything except the starter motor.

The existing brown wire is probably 6 inches long, but mounted on the
bulkhead, so extending to an ammeter would require an additional 18
inches or so, in both directions.
--
Graeme