Different voltage between units

[rvg8tor]

I am testing and getting to know my panel today and noticed something odd. I have a D180 and D10A. When I bring up the EMS info on the D10A the voltage on it is different from what I see on the D180 by about .6V higher.

I found this odd since I thought the EMS info on the D10A was just a repeat of the info on the D180. Anyone seen this before? the big question is what is the real voltage, I am using a power supply putting out 13.8 volts. The D180 reads 12.6 and the D10A reads 13.4.

The only thing I can think of is that the D180 is on my E-bus and the power to it goes through a diode to prevent back flow of power when feed via an alternate feed path. The diode does cause a voltage drop, but I thought the D10A when on the EMS page is just repeating what is on the D180.

 

[RotaryLancair]

I suspect that each of those units is reading the voltage it is running on. If you have one on the endurance buss and the other on the main buss, that could explain the difference. If you have a switch to select the endurance buss directly, you could flip it and that would cancel the difference between the busses, which would help explain it.

RotaryLancair

 

[dynonsupport]

They do each report their own voltage levels. So there's probably some voltage drop across the wiring/components you have hooked up to each device.