Voltmeter Behavior, Verify Accuracy Options

[Superhawk996]

Starting a new thread in response to @emeryGT 350 comment in another thread as follow up

Here’s the background:

[emerygt350]

I think of it more as a dummy light or perhaps a 'general suggestion' about the charging system. However, I have found mine does some disconcerting things that don't allow me to even use it that way. If it's sitting on 12 that scares me, but then I check the voltage and its 13.4. another day it will be at almost 14 and the voltage will be 13.6. That's not helpful. The original lines to the gauge now operate a relay which has a direct (fused) connection to the battery. Hmmm.... I should double check my ground shouldn't i?