Digital Ammeter--Looking for Source

npalen · Apr 2, 2017

Looking for a digital ammeter for my tractor that reads negative as well as positive amps. The digital ones I've seen only register the amps in one direction. Any help?

k0ua · Apr 3, 2017

DC -1A Digital Positive Negative Current AMP Meter Backlight ON/OFF Blue LCD | eBay

Maybe this?

npalen · Apr 3, 2017

That should do the trick! Thanks for posting.
Thinking about ways to provide the external power supply: Wonder how long a 9 VDC battery would last given the Power consumption: <= 20mA?
Perhaps a way of switching the 9VDC off when ignition switch is off. Or spend a few dollars and get a DC to DC isolater?

k0ua · Apr 3, 2017

npalen said:
That should do the trick! Thanks for posting.
Thinking about ways to provide the external power supply: Wonder how long a 9 VDC battery would last given the Power consumption: <= 20mA?
Perhaps a way of switching the 9VDC off when ignition switch is off. Or spend a few dollars and get a DC to DC isolater?

The 9 volt battery would be a pain.. Always dead when you need it.. I would keep looking for one that did not need an isolated power supply. Or you could do the isolated power supply thing I guess.