Here's an esoteric question if ever there was one - has anyone thought of driving the ammeter with a closed loop current detector? For the non-electronically minded this is what a current measuring clamp meter uses i.e. you stick the battery cable through it and it can measure current to/from the battery non-invasively. I say this because when I fitted the round instruments to my car I deliberately chose NOT to fit the shunt as it looked like an open invitation to cause a fire with the entire output of the battery or alternator going through here. I reckon all that's needed is an appropriate module, a DC regulator/converter, likely an op-amp as driver for the meter and a few resistors (likely variable for calibration/zero point setting) for about £30 with no cable chopping required. Anyone interested in such a thing if I ever find time to prototype it?
Closed Loop AC/DC Hall Current Sensor CYHCS-D5S-100A, Output: 50mA-100mA, Power Supply: ±12V ~ ±18V, Window: 20mm
Closed Loop AC/DC Hall Current Sensor CYHCS-D5S-100A, Output: 50mA-100mA, Power Supply: ±12V ~ ±18V, Window: 20mm