Is a 30 amp fuse big enough for two 130 watt hella's? Hooked every thing up, 12 gauge wire, 50 amp relay, heavy duty switch. Tried lights worked good, that night was goin to see what they were like in the dark and as soon as i flicked the switch lights flicked for a split second then went out. Checked fuse and it was blown. Next day checked every thing out checked all grounds, everything is hooked up right all grounds look good, blew 3 30 amp fuses in a row. Any ideas? should i try a 40 amp fuse or do i have other problems. Thanks

 

Try this link:
http://www.the12volt.com/ohm/page2.asp

Your draw or current load works out at 10.83333 amps.

As long as 12 AWG supports that load, you should be OK with 30 amp fuse.

There are some AWG wire calculators on the web, that will also check that for you.
Link: http://www.powerstream.com/Wire_Size.htm

If that's OK which it seems it is.........you gotta' look for a short to ground causing your fuse to blow.
Al.

 

Wire your lights for the load - then fuse to protect the wires.
130 watts x2 = 260 watts
260 watts/12v = 21.667 amps,

So I'd use an absolute minimum of #12 conductor, which wouldn't quite be enough (# 10 would be better), and fuse for that conductor size, a #10 in house wiring would have 30 amp overload protection, so a 30 amp fuse should do, and not blow.

Do you have any means of clipping the current with a DC ammeter (clip-on) to determine the actual draw per bulb?

 

Oops....forgot he had two lights duh lol.

Al.

 

30A fuse is plenty for a pair of 130 watt lights, I've got my 130 watt Cepeks running through a 30A to a 40A relay and no problems. 12 AWG wire is also what I used so that should be fine as well. Time to pull out the meter I think.

Just out of curiosity, why the HD switch if you are using a relay? The switch should only be drawing about .3A if it's wired to a relay...

 

shoudl be a big enough fuse. my 2 130 watt KC HiLites have a 30A fuse inline

 

I agree. 12awg is more than enough. Car electrical isn't the same as House electrical and therefore you can squeeze more out of the same guage wire for a car than you can for a home. You can also get away with using a 25 fuse as well. You could actually get away with 14awg wire and 260W worth of lights, but that's reaching the wire's current limits. Still can be done though.

As far as the switch, it depends on how it's wired Hammer, but even then, the switch would not cause the fuse to blow. I say check your connections because you must have something touching or arching. I would double check the leads inside the light casing. I made sure I used totally sealed terminal crimps so there was no contact going on between the leads. A bad ground or loose terminal will not blow a fuse. i would also double check to make sure your relay is hooked up properly!
The above 12volt link has relay diagrams

 

The more I think about it, I ran 14 AWG on the truck for the Cepeks cause I had it already, so your problem for sure ain't the wire. I knew 14 would be fine especially since I'm only running about 5' to the relay and grounding to the big a$$ 2 AWG on the winch about 14" away.

I had to go buy more when I wired the Jeep for the 130 watters I mounted on the winch and went ahead and bought 12 AWG cause it was the same price and only about 6' less on the spool. Also since I was installing a "quick connect" plug for power I had a couple of runs of about 8' and the "plug" inline, I knew that the thicker wire would be a little better.

 

a pair of #14's would be absolutely fine, but the combined voltage drop caused by 21-2/3 amps through a single conductor would cut into your usable voltage at the bulb due to I^2R drops. if you haven't bought the wire and stuff yet then now is the time to make no comprimises.

That being said, I've done a lot of "I had it on hand so I used it" stuff and have been quite satisfied with the results.

 

I bought a heavy duty wire harness for these lights and thats the switch it came with.