I think it depends on how the Voltmeter is wired into the system. On My +8 Bitsa I ran a wire with diode from the Alternator post to the gauge. I wanted to know if the alternator was knackered. With a Delco Alternator I get 14 volts immediately and that is where it stays.
But I too enjoy the vacuum gauge. When it goes to 0 I shift gears. No Brainer
