G3X voltage readings?

My G3x (non touch) is indicating, engine running, 13.1V. After reading numerous
post re: the PC680 battery maintenance, this appears to be lower than the desired voltage for the 680.
Using my digital volt meter, temporarily connected to the ground buss I am reading 14.1V. with the engine running.
A 1V difference? I am relatively sure the 14.1V reading is correct, is there any way to adjust the G3X to indicate the correct buss voltage?
Dick

Were you able to confirm the 14.1V reading at the same location as where the G3X is reading bus voltage?

I would first check to see what/where the voltage input to the EIS is, its more likely that is really the voltage that it is seeing at the selected input and not a G3X calibration error.

Hello Dick,

You might also check to see how you are monitoring bus voltage.

As explained in the installation manual, you may directly connect a bus wire to a voltage input on the GEA 24 or GSU 73 engine monitor, or you may simply ask the engine monitor to report the voltage of the supplied aircraft power that it is using.

The latter method is convenient and does not require any additional wiring to do bus voltage monitoring, but that voltage input to the engine monitor is highly filtered/protected, so may be a bit lower than the main bus.

As others have suggested, you may also just have a voltage drop before the signal gets to the engine monitor.

Thanks,
Steve

Also, you didn't mention bus architecture. If you are powering the G3X from a diode-isolated endurance bus, the isolation diode will cause a more-or-less 1V drop in supply voltage, depending on type of diode and load.

What kind of DVM? Fluke or Harbor Freight?

snopercod said:

What kind of DVM? Fluke or Harbor Freight?

Click to expand...

Probably wouldn't make more than a couple hundredths of a volt difference. I've got a couple of Flukes, and have had several HFs scattered around for convenience. The HFs are always very accurate, until they don't work at all. Short life is their biggest issue.