Dual voltmeter wiring

Greg. I have 2 volt metres in my Troopy and just wired them directly from the batterys. Yes they are 'on' all the time but the current draw is miniscule and have had no issues these last 4 years. Adding a switch is just extra wiring to stuff up down the track. KISS principle mate

Hi Greg,
I have this one fitted -
Voltmeter

Runs all the time and the lecko says it draws bugger all current.

bill

Hi greg, have led voltage gauges in the 200 and they are hard wired like the other replies have said and current draw is bugger all.

If you are worried about it, pair up the two negative wires and put a switch on the negative wire.

,
As said, they probably draw only a few milliamps and could be left on at all times.

However, in my vehicle, the two meters are combination volt/amp meters using induction ammeters which draw a bit more current so I have them controlled by a 2-pole relay from the ignition circuit.

Incidentally, it is very interesting to observe the relatively large charging current (50A) to the cranking battery after an engine start, then how quickly it falls to zero charge.... less than a minute.

Thanks very much for the advice Folks. Looks like no switch needed. That's the way I'll go.
Cheers All..

I use two digital voltmeters and use a single pole switch to earth their negative lines to neg line. To be able to switch it off is a good thing because sometimes at night the brilliant LED numbers are bright and can reflect in the side mirror and side views, depending on meter position. Also if they are off you are not advertising additional gear you have fitted by attracting attention.
When making the connection of the neg side from the switch, make sure it goes to as near as possible to, or at, the battery negative/s. That way you get the actual voltage indication and not a, slightly higher than negative point, which will reduce the indicated display and make you think the system is less than it really is.
PS. Cranking amps of 100 amps for 3 seconds is not much battery discharge at all and will be replaced very soon by the alternator which is only a couple of volts higher than the discharge difference of voltage.

Personally I would avoid the use of switches or relays etc in the circuit as dirty worn contacts etc can cause the voltage display to be inaccurate, but then I guess it will depend on how accurate you want the reading to be.

I use a DPDT (double pole double throw) centre-off switch with a LCD voltmeter. Image Both negative and positive lines selected by the switch. The OFF position is required because the backlight operates whenever voltage is presented, and can be a distraction as others have mentioned.