Ampere & Volt Meter?

i just picked up a a volt meter and ampere meter foor a good deal, and i wamt to install them in my truck (2007). I already built a box for them and have a good place to mount them, but i'm getting out of my area when it comes to the wireing.

for the volt meter, the first question is, what where in the fuse box do i tap into so that the meter only turns on when the key is on? the second question, is, can i just ground it to the frame as if it were a set of lights, or do i have to bring it to the negative side of the battery?

as for the ampere meter, i am completely lost...can i use id to measure the amperage that the battery is putting out to the whole truck, or is that amount too hich for a 50 ampere gauge? and second, where would i tap the wires into for this?

I'm usually pretty good with wireing and electronics, but i've only ever used meters before, never had to set them up. thanks for the help

 

i was thinking that would be the case. i have 3 sets of aux lights, is there a way to hook it up to all 3 of those? and would that be within 50 amps?

 

it's cheap, but should get the job done. the back has two connection points, "+L" and "+B".

 

there are 3 sets of 55 watt lights. i can also wire it to my cb radio/pa, air compressor, small airhorns with a different small air compressor, and maybe one or two other things. i don't know exactly what they draw, but do you think all of those would get a reading. my goal is to essentially see what i'm drawing from the battery asside on top of what a truck with no accessories would. even 10 amps would probably read on the gauge, but i'm a little rusty of the math to figure that out.

 

that works for me. the only other thing i'm worried about is that you said to wire whatever i'm running through it in series with the meter. that essentially means that i combine everything into one wire that i can plug into the back of the meter. what gauge wire should i use to be safe. i have a spool of 14 gauge sitting around. is that big enough for that much current running through one wire?

and by the way, thank you for all of the help, people like oyu are why these forums are so helpful

 

oh, i forgot to ask earlier, what is the best way to tap into the IGI fuse? should i wire it in from beneath, or is the best way to go, to get one of those fuse taps. with the wire sticking out of it?

 

bump

 

For the amp meter I'd say to use at least a gauge of wire that can handle the max current measurable by the meter (probably 6 gauge or bigger for a 50-amp meter, and make sure the insulation can handle the temperature inside the engine bay). If you want to measure the total draw on the battery you'll want to at least match the gauge of the hot battery lead (at which point it might be worth it to look for an amp-meter with a sender unit instead of just wiring a dial in the dash into the battery lead).

For the volt meter, you can hook that from any switched fuse to the body to have it read only with the key on. The ohms on a voltmeter are so high that the draw is miniscule and there's no big downside to having it measuring full-time if you want. Only using it with the engine on will only really give you a read on whether or not the alternator's working properly while having the meter on full time will let you see the battery volts when the alternator isn't active (not neccesarily a good indicator on a depleted battery since it's possible to have a 12V reading on a batt that can't push enough cranking amps to start up). I've installed Vm's wired straight to the battery terminals before without causing trouble (probably a waste of wire since you can get the same result wired to the fuse block/body....).