Need help from my LED lighting expert friends at tundras.com :)

Hey y'all! I am working on an LED lighting set-up, and could really use some help so I don't catch my truck on fahr!


I have the following LED light bars that I want to install:

42", 540w, assuming a max pull of 45 amps
42", 540w, assuming a max pull of 45 amps
36", 108w, assuming a max pull of 9 amps
31", 150w, assuming a max pull of 13 amps
Total max pull = 112 amps

I have a single relay rated at 200 amps, so I am assuming that should be good. Also, I want to run all four of these light bars off one switch.

My question is in regards to the fuse for the wire that runs from the relay directly to the battery. When I started this quest, it looks like I incorrectly assumed I would need a 200 amp fuse, to handle the total load. But after reading some articles on the interweb, unless I'm misinterpreting, the fuse's amp rating should be based on the amperage of the LED bar pulling the least amount of amps, in this case, the 108W bar (9 amps, call it 10 amps). But this just doesn't make sense to me, for if all of the LED bars combined pull a max of 112 amps, wouldn't a 10 amp fuse be sure to blow? But if I were to use a 200 amp fuse, then I might open myself up to some wire melting if one of the LED bars short out, right?

If someone could dumb this down for me, or even give me a recommendation on what fuse rating I should use, I would REALLY appreciate it. I know I'm hyper-confused on this, and am probably not understanding how it should work. Or, if I shouldn't even be running all of these light bars off one relay, please let me know how you recommend I should wire all of these.

Thanks so much in advance for your help!!

 

Yes, they would all come on at the same time. We drive hunt down here, and if one is bagged close to dusk, we need all the brightness we can get in the field to find it.

So if I ran a fuse block between the LED bar and the relay on each individual light bar, would I still need a fuse block between the relay and the battery?

 

If your calculations are correct, your main fuse would need to be above your 112 amp max working load. I would get a 150-200 amp 12 volt breaker for the main circuit & then separately fuse each individual circuit right after the breaker.

Good luck!

BTW That's a hella lot of light, wear sunblock & eye protection!

 

Why does one need that many light bars?...

**just read that you’re using them for hunting.

Still would like to see your final setup. Sounds ridiculous.

 

Just to be clear, battery to breaker to relay to 4 fused circuits.

 

Thanks Paul! So to be clear, I would have:

- A fuse between the relay and the battery, rated at like maybe 120 amp
- Individual fuses between each light bar and the relay, each fuse rated to the approximate amps each light bar is pulling

Sound right? Thanks again!

 

Haha posts crossed!

 

I’ll post pics when complete!

 

Yes, that would work.

 

Thanks again Paul!

 

I'll agree with the others on fusing the main and each light.

I'd skip a relay though and use a solenoid. They hold up better long term under high amp draw.

Like this guy. Wiring is similar to a relay.
http://shopping.murcal.com/Catalog/PowerSeal-DC-Contactor-Family/684-1221-012

 

Oh man I didn’t even consider a solenoid, thanks @Festerw !!