Howdy yall, i just bought two off road lights for behind my grill and i wanna hook em up to a relay, what size ampage wise do you guys suggest? i know that i have a 50 layin around in the garage! thanks for the input.

EDIT: they each pull 100 watts, so 200 total

 

Didn't come with one??

 

it comes with an in line fuse, but everything i read online said to use the in line fuse and a relay! maybe the thing you were looking at was the switch ahah

 

I got two 100 watt KCs with just the fuse they came with and havent had any issues at all with them.....relays and I arent exactly fond of eachother

 

They usually come with a relay wired to the fuse. But can't remember off the top of my head what size mine is though

 

yessir, you can run it with just a fuse but im pretty sure you get like 2x light output if you use a relay, also check this out! it helped me a lot http://www.fullsizebronco.com/forum/...ad.php?t=91301

 

Amps = Watts / Volts
? Amps = 100 Watts / 14 volts
? = 7.14 A

Each light will pull 7.14 Amps of power when the truck is running. Ish A little bit more when the truck is off, as you will only be drawing power from the battery, which will be closer to 12.5 - 13 volts. So to be safe, say 10 amps a light. So times 2 lights, means switch it with a 20 amp relay, you can go as high as you want, as long as your inline fuse is only rated for max 20 amps. 10 amps if you're fusing separately, which you shouldn't, but it can be done.

wire sizing you can look here.
http://www.windsun.com/Hardware/Wire_Table.htm

Part you want is size:
#12 = 6.6 feet max.
#10 = 10 feet max
#8 = 16 feet max

 

10-4 thanks a lot man!

 

Make sure you get one that can handle "continuous duty". Although your lights won't be on all the time, the inducers in the non contin. ones aren't very good and are mainly for quick switches

 

If you need the schematic for hooking up your relay, I have a couple pics in my pictures on here under the service manual section of my page.

I would use the 30 amp Bosch 5 terminal style relay. You can buy them cheap on ebay. I bought 10 with harnesses for 14.75 shipping included. My local auto/electric supply wants about 8 bucks a set. This is one of the most common relay set ups and can be used for any thing that pulls high volume of power and needs a constant source.