This wiring diagram is from our dual meter series. The single amp meter uses the same internal power supply, so hook-up instructions are the same, however there is no voltage measurement.
There is a big difference in this unit's internal power supply and the ones you will see being advertised for powering panel meters.
Hook up four wires and you are ready to go. Push the switch to turn the meter on. Push again to shut if off. That's about it, super simple, yet super functional!
Most "meter" suppliers you find use a low cost linear voltage regulator. This is completely useless for 48 volt systems, and on 24 volt systems, you better have a big heat sink and expect to use about 1 amp of power just running a single meter. This supply uses a super efficient high voltage switching regulator, this is not cheap, but it is necessary!
An amp meter requires total isolation from its power supply verses its sense leads. This is difficult to accomplish when you want to use the voltage available at the shunt to power the meter directly. Many DC to DC isolators are available if you wanted to build this type of supply yourself, but then you still have to reduce the incoming voltage to the level of the DC to DC isolator -- and you have to prevent the meters power demand from dropping the voltage across the shunt and fooling the amp meter into thinking there is more amperage than is actually occurring. A voltage drop of only .0075v will cause an amp reading of 10 amps! We have accomplished this and it is ready to go.
This supply uses a super efficient pre-regulator to allow higher than normal incoming voltages to properly handle 48 volt systems in an overcharged state or that are receiving high incoming charge voltages.
You can change a jumper to cause the volt meter to measure the voltage at the shunt, or the voltage of the supply (battery voltage).