Join Date: Mar 2002
Location: Austin, TX, USA
Re: Sunpro Gauges
In a stock setup, amperage is read with a millivolt meter connected accross a milliohm resistance. In a car's amp meter circuit, the amp meter is connected in paralell with a wire running between the regulator and terminal block behind the battery. The 3 or 4' of wire provides just enough resistance that a voltage drop will form accross it. If the voltage at the terminal block is higher than at the regulator, the amp meter reads discharge. If the regulator side is higher voltage than the terminal block, the amp meter reads charge.
Other amp meters have the resistance internal to the meter. So instead of being connected in paralell to the wire between the terminal block and regulator, the amp meter *IS* the wire between the terminal block and amp meter. In that case, the wire size is likely to be larger than a stock amp meter circuit.
I'm not sure which type your sunpro amp meter is. But in either case, both wires are hot, so they must be insulated from the meter body by plastic washers or some-such.
68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI