New supply to voltmeter

[TheBeastie]

A while back I queried a low voltage reading on VDO voltmeter and there was suggestion to run new "known" feed from battery to the meter. I would now like to do this but the existing supply is via ignition switch so voltmeter only on when ignition on (saves drain). If I were to do it would I be best to run new, heavier than the original, wire to ignition switch and then also replace the wire from the switch to the voltmeter?

It was also suggested check earth so I will run a new earth lead back to battery at same time to make sure.

If not this, then how best to do?

Thanks and best wishes

Malcy

[Puffernutter]

If I were doing it, I wouldn't worry about changing any wires between the battery and ignition switch, the voltmeter takes such little current. If you wanted to run a separate wire back to the battery, then fine, but with mine, I just attached it to a convenient earth in the dash area. The wire doesn't need to be exceptionally heavy.

Cheers

Peter

[Les Brock]

No need for a large cable as the voltmeter is only carrying the current taken by the meter, make sure its fused tho !

clean earth is good, I would just take one to a common earthing point

HTH

[MrKev]

What do you assume the voltmeter to be measuring?

If you assume it to be battery volts, then I would run a pair of cables from the battery - one +ve and one -ve.

If you assume it to be vehicle volts, then I would run one from a decent grounding point, and one from the fusebox.

The reason behind my logic is that often the fault being looked for is a faulty ground point off the battery, and as such the first method will not show the volts collapsing when attempting to crank the engine, but the second one probably will. The second method may lead you to replacing the battery when there is no battery fault, whereas the first would show that the battery is in good health and thus prompt you to consider the other possible faults.

With method 2, the voltage reading will collapse with either a poor ground or a poor battery (or a poor positive connection elsewhere for that matter).

Kev

[western]

for a single voltmeter connect to one of the White wires which is ignition controlled & will automatically switch off when ign is off, that's how the factory wire it.

my 2nd voltmeter [for winch battery] is wired through a 4 pin relay, so it is ignition switched on/off & the voltmeter reads direct from the battery.connected as per my diagram below, [ignore the note at bottom]