Power source directly from battery

[agentorange313]

Hey guys,
I have recently been given multiple AEM digital gauges to use in my car. So far all my gauges have been analog (if that's the term to be used), and did not require a power source. I have searched the forums for a way to hook up my gauges to a 12v power source that will only draw power then when the car is on. So far the best option is hooking up the gauges to the ignition.

Spoolio suggested "i would connect all of them into their own power source, or connect them all directly to the battery with a fuse jumper and a switch, or into different fuses, i wouldn't tie them all into together you may not have full power into each gauge, just hook them up separate."

I would rather hook all the gauges to the battery and use a switch to run power to the gauges. I need to know exactly how to hook these gauges up the the batter.

What size wire should I use?
What size inline fuse should I use?
What size switch should I use?

If there is any way to improve this idea or a better route for lighting up my digital gauges (3 digital gauges all requiring a 12v power source within the cockpit).

 

[RichardA]

the gauges only need power at night besides the volt meter
so wire the lights on the gauges to the running lights through a relay and power the volt meter off the ignition

 

[agentorange313]

I think you miss read what I was writing. The digital boost gauges from AEM need a constant 12v source, DAY OR NIGHT. Its a digital gauge and without power they do no display the current boost/temp/pressure.

 

[RichardA]

ahh ok then just tap off the ignition wire to a relay run a fused wire from the battery to the relay and use the relay to power the gauges

 

[agentorange313]

thanks for the input,

can someone still answer the question about:
What size wire should I use?
What size inline fuse should I use?
What size switch should I use?
What size relay should I use?

Are there any write up or reference for the wiring? I am in very unfamiliar territory.

These question still apply even with RichardA's answer

 

[knochgoon24]

The gauges have a very low amp draw. I think I used some 16ga wire that I had laying around.
For a fuse, just use a 5amp one.
You won't need a switch with a relay run off the ignition wire. Your key will be the "switch".
Any 12v relay will do. A 30amp relay from your local auto store or radioshack will work fine.

 

[agentorange313]

awesome I pretty much can do it now on my own.

As far as the 5amp fuse, are you saying to put that before each gauge? Is there a need for another fuse before the gauge after the inline 30amp fuse to the relay?

 

[knochgoon24]

No, you just need one 5amp fuse. I'd put it between the battery and the relay.

The 30amp refers to how much current can flow through the relay. It's rated to 30 amps. Anything more, and it may heat up and burn out.

 

[spawn87]

Well i dont smoke so i had no need for the cigarette lighter so i took it out and ran a wire from the fuse to the gauges works fine because that is a constant 12v source when car is on.

 

[dsmcurse]

why not just go off the stereo wire. you know EXACTLY where it is. its 12v that only goes only with the key. very easy to do. and for the lights that are in the gauges. you want them to turn on with your head lights right. remove the plastic trim peice thats on the floor and covers up the edge of the carpet, you know plastic guy thats right there when you open up the door? cant think of its name right now. remove that and you'll see how there is wiring under there. get a test light and stab wires while turning head lights on and off. the wire your lookin for is a green with white stipe. but any how test light while switchin lights on and off youll find it. tap into that wire. to make your gauges light up with your marker lights/head light. as far as the wire size number 14 is ok kinda big i guesse. probably AWG 16 is best