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Wiring h3 Flood Lights, need some advice.

Stomis

Stomis

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So I built my roof rack this weekend but have taken my time and decided to get the lights, shovel, axe etc on it all at once so I can paint it in one shot.

So I went to start running wire for the flood lights. Theyre HF lights so I figured they were like a typical ditsy light bulb that I could wire straight through a switch. Well apparently the damn things have friggin h3s in them. So now I need to figure out what I need to wire them...

Im no putz I know they'll probably need a relay but Im wondering what gauge wire I should use?
 
Just figure out what wattage the lights are then use the appropriate wire that will support that wattage.
 
Yeah I just did that. Two 100watt h3s per switch is 18amps. 12gauge is rated up to 25amps so thats more than enough. I dont even need a relay seeing as how Im using heavy duty switches.
 
Good luck guys.
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I would highly recommend using relays. I have a light bar on my roof that has 10 forward facing, 5 rear and one to each side, the way it's wired i have 7 relays just for that bar. Also use a decent fues assembly.

Just because it's a heavy duty switch doesn't mean it may like all that power going through it for extended periods of time.
 
4xcrazy said:
I would highly recommend using relays. I have a light bar on my roof that has 10 forward facing, 5 rear and one to each side, the way it's wired i have 7 relays just for that bar. Also use a decent fues assembly.

Just because it's a heavy duty switch doesn't mean it may like all that power going through it for extended periods of time.
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Mmmm Fair enough. Now that Im thinking about it Im recalling when my 87 had an electric fan in it on a switch. Was a 30 amp fan with a 30 amp switch, no relay. Bought it like that and the mofo toasted that switch in a few weeks after I bought it.

Now Im wondering if I should make a weather proof box to hold the relays up on the rack and run an 8 awg wire to the roof to power the relays or if I should keep it all in the cab...
 
I like the idea of a remote weather proof box with the relays and fuses inside. This will allow you to easily add more lights later like some auxillary reverse lights or flood lights off to the sides. Or maybe some forward facing spot lights for longer range. I used an old computer power supply case to house mine inside the cab behind the seat, not ideal but it keeps them safe from being bumped around. They control the four light outputs on my roll bar. One of the relays does double duty by powering a 12v cig plug in the bed when not energized.

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If you wanna take it a step further, you can pick up an H3 HID kit from ebay for about 35 bucks. They give off 2-3 times more light output than a 100w H3 bulb while only using 35 watts each. I just got a set and put them into some cheap HF 6inch spot lights and holy crap, I cant even tell the headlights are on.

Are they the HF "tractor" lights with a rubber housing and a tiny red wire?
 
Well, you have already got the lights, so that recommendation is out.
But, I agree, a heavy wire with relays is the way to go.

As for the wire size, 12 is rated for that amount, so it will not overheat, and is safe, but remember the window motor threads.
The wire for them is certainly rated heavy enough for that use, but the motors still drag.

The primary rating for a piece of wire is mostly the temperature rating for the insulation vs its temperature rise under that load.
Voltage drop is not always figured in to the calculation, though it should be.
You are not going to get much even with 12 gauge, but bigger is always better.
Plus, if you have a heavy line going up there, you have the basis to add other stuff if you want to.
Like a remote controlled spotlight, or a heavy light bar or a bed light so you can see how to get stuff out at night.

Assuming its a pickup, I don't remember offhand.

If you had not already bought the lights, I would have suggested looking into LED light bars, floods or spots.
The prices keep dropping, and the light to current ratio can't be beat except possibly by an HID.
 
saw an LED light bar out at the dunes July 4th. Holy cow. I wish I could have stopped the guy and checked it out better.
 
He has a history of goofy posts like this...in his 7 total posts. Dunno if it's spam or oddness. Just report it.
 
AJMBLAZER said:
He has a history of goofy posts like this...in his 7 total posts. Dunno if it's spam or oddness. Just report it.
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I've already been watching this guy. Spammers can't just show up and post links to URLs anymore, so now they seem to hang out for a while and make irrelevant posts trying to see if the rules eventually change.... :whistle:

My ban hamster is waiting for this guy to screw up....



:usaflag:
 
They're getting more and more crafty.

Greg72 said:
I've already been watching this guy. Spammers can't just show up and post links to URLs anymore, so now they seem to hang out for a while and make irrelevant posts trying to see if the rules eventually change.... :whistle:

My ban hamster is waiting for this guy to screw up....



:usaflag:
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Is that like a ban gerbil?
 
There is really nothing inherent in a relay that can support more current than a switch. You can get either to handle almost any size load. But you have to know what you've got. There are cheap (read "misrated") varieties of both. The main reason you see people push relays here is because they allow you to shorten the wiring path - in other words bypass stock wiring that is too small and too hard to follow/replace. So the choice on whether to use switches or relays depends on the path of the wiring. With the price of copper these days, cutting out a few feet of heavy cable almost pays for a relay.

But switches are dead simple. You can always run two switches and two wires to divide the load in half.
 
I thought the idea of the relay was to take the initial "hit" of current so it doesnt fry the switch?

I vote for Relay btw. lol
 
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