Volt Meter Wiring

[2bad4u]

I've purchased a couple of 12v volt meters off of ebay, one is going to be wired to the second battery at the rear of the car (simple enough) but my concern is wiring to the main battery for the 2nd volt meter.

Having read stories on here about people cooking their ecu's, etc, by simply wiring in switches, I want to know what others have done with their volt meters. It is a simple 2 wire (+ve and -ve) volt meter so did most people wire it straight to the main battery? If not then where?

My car is an NW.

Cheers
Warren

[GHendo]

Just wiring a volt meter isn't likely to cause you any dramas. You really are going to just have the positive lead connect to the battery's + and the negative to the - but that will give you a reading even when the ignition is off - if that is what you want. If you only want it to give you a reading when the ignition is on, you will have to get a bit more creative.

Wiring in switches can be a bit more complicated depending on what the switch is switching and where it is picking up power etc. Some switches can be internally wired so that they can give problems that you don't expect and you need to use diodes to stop unwanted effects.

Cheers

Geoff

[2bad4u]

Thanks Geoff

I was in two minds about how to do it. With the second battery I was just going to put a momentary / push button switch in line. With the main battery I may just take it off the back of the cigarette lighter then so it's only with ignition.

[GHendo]

That should work fine - just remember with the switch, you usually use the switch to break the earth, not the positive. 90% of the time it probably wouldn't make any difference - it's probably more convention than anything - also means you have less positive wires running to switches etc.

Geoff

[Nivo]

I just used a relay for mine triggered by an accessories power feed in my NP. As soon as the key is turned the volt meter shows whats in the 2nd battery. I also used that same trigger wire to show what the main battery has on another volt meter.
Cheers
Nivo

[2bad4u]

OK, one for the sparkies. Does this wiring setup look OK for what I want to do.

Voltmeters only coming on with accessory power.
Momentary switch to check Aux battery voltage without turning on ignition.
Normal 4 pin 20a relay.

Anything I've missed?

Cheers
Warren

[2bad4u]

Finally got around to wiring in a couple of volt meters (as per the wiring diagram above). Installed them near the foot rest so they are easy to view and not in the way. Put a momentary switch on the auxiliary meter so that I can check it without turning on the ignition.

IMG_0423 by Wardon Photography, on Flickr

IMG_0422 by Wardon Photography, on Flickr

IMG_0421 by Wardon Photography, on Flickr

[Pajshomoneroguntero]

Looks good.

Will the Aux read when the IGN is on or only if the momentary switch is pressed irrespective of the ignition?

[2bad4u]

Aux reads when ignition is on and can be read (via the switch) when ignition is off.

[TC.Barky]

Great setup. Like the momentary switch idea, very clever

[MyExceed]

Nice job, could you post a link to the gauges please

[2bad4u]

eBay is your friend........

Voltmeter Link

Got the momentary switch from Jaycar.

[KPJero]

Hey guys,
I installed the dual voltage monitor from supercheap. It was $13. It's wired always on. Surely it won't drain either battery sitting always on

[Keithyv]

It will, but depends on how much it draws of course as to how long until it flattens the battery.


You'd need to measure the current it draws to make a good calculation but my semi-educated guess would be not to leave the car idle for more than 3-4 weeks.

[KPJero]

It will, but depends on how much it draws of course as to how long until it flattens the battery.


You'd need to measure the current it draws to make a good calculation but my semi-educated guess would be not to leave the car idle for more than 3-4 weeks.

Ah yeah fair enough, it's my daily driver so drive it at least once a week haha