If Jim, or I, were to run a USB plug w/ voltage readout wired off the alternator, with it's own fuse and a ground, it WOULD read the alternator's volts though, correct?

And when I mentioned I was going to do this USB/volt readout plug at the old cigarette lighter, I should have been clear and mentioned that I was NOT planning on wiring it up with the wiring from the cigarette lighter; sorry about that. I will safely cap that cigarette lighter power lead off.