The terminal on the right (facing the meter face) is the "charge" side, and should be hooked to the battery.
On the face, the meter on my '55 has a "D" on the left for Discharge, and a "C" on the right for Charge.
These are heavy wires (10 AWG minimum), so make sure the spade terminations must be TIGHT. Otherwise the wiring will get hot at the gauge.
