So I got the 6in Harbor frieght lights (12v 55w h3 lights) and i went and bought Hella 130w lightbulbs 7.99 each to replace the 55 watters that are in thier, I could'nt find anywhere it said i could'nt do that, so I bought 12ga wire, 30amp toggle, 30 amp inline fuse. Is a 30 amp relay good enough?, which the part store carries and was out of at the time? or do i have to get a 40 amp relay? If i get a 40 amp relay do i have to switch the toggle and inline fuse to 40 also? Just looked on KC's Website and thier dual 130w h3 light set up uses a 40 amp relay, Basically I need to know if I have to return the crap i bought and buy all 40 amp crap

 

i don't see how those lights could draw 30amp. i don't know if my math is right or not but i think the 1 light should draw about 11amp

 

Each light will draw 13 amps when warm, but there is a surge when they first turn on and the hotter the bulbs get the more amps they will draw. 30 might work, but you'd rather run 40.

I would run 8 gauge wire with a 5 amp toggle and 40 amp inline fuse and at least a 40 amp relay (a higher rating will last longer). 12 gauge wire is going to cause a severe voltage drop at 40 amps, meaning that your lights will be dimmer. 6 gauge would still even be appropriate. Just keep the wire length down to decrease voltage drop.

The toggle switch is just that, a toggle for the relay, it is basically a mechanical switch to turn on an electro-mechanical switch (the relay) so it does not need to be rated very high. That is largely the purpose of a relay, and also to decrease the length of the load-carrying wire. 12 gauge wire is plenty for use between the relay and the switch.

 

Wow, usually I get on an "off-road lights" thread and have to talk people into using thicker wire than they were intending to, but you REALLY believe in over-kill, LOL. Even though I don't work in the field any longer, I'm a licensed electrician and was a car stereo/alarm installer when I was in college.

First of all, don't use a 40A fuse with a 40A relay. The purpose of the fuse is to protect the rest of the components including the relay. ALWAYS use a fuse that is rated below the relay. Also, the surge when turning on a pair of 130 watt lights is between 10-15% according to my meter. So you don't need to over-buffer for surge as much as you may think. Lastly, you don't need anywhere near the wire thicknesses you indicate (although there is nothing really wrong with running thicker than you need). When running a switch through the relay (and not in-line which is NEVER good), there is only a .3A draw on that wire. Hell, 20 gauge would be plenty. On the wires carrying power to the lights, 12 gauge shows no measurable voltage drop at 6' with a pair of 130 watt lights on my meter.




I have a DIY in the 3rd Gen FAQ section on running lights. In the last section, there are relay/fuse/wire suggestions based on NEIS (National Electrician Installation Standards).

https://dodgeforum.com/forum/3rd-gen...nd-relays.html


also, you need to pop the lights open and see what gauge wire is actually INSIDE the lights. Even the higher quality Hella 500s that come with 55w bulbs doesn't use a gauge thick enough for even 100w bulbs. Running 12 gauge or larger wire won't do you a bit of good if the wire inside the lights is too thin and melts on you.
I upgraded a set of Hellas from 55w to 100w for a buddy this past summer and re-wired the inside of the lights. It isn't hard and doesn't take long...

 

155w lights are pretty extreme, and there are two of them. I think that 12 gauge would work, but if I were wanted high quality results, I would use a lower gauge.

About the fuse, fuses are mainly intended to protect the wire. If there is too much current running through the wire, you run the risk of it catching fire. That is the main consideration in fusing.

 

Thank you for your Ideas and the link, I will tear the lights open to check the gauge of the wire. I Appreciate it. So are you saying there's a 155w h3 bulb i could buy? Funny Hammer i used that same pic yrs ago and have it printed out to wire my back up lights.

 

Your truck will slow down when you turn them on, due to the thrust generated by the volume of photons being emitted.

 

he's not talking 155w, he's talking 130w. If we were talking 155w I would say 10 gauge minimum. I've never seen a 155w H3, but that's not to say one doesn't exist.

And I agree with you, the primary purpose of a fuse is so the wires don't fry, but my point was, if the fuse and relay were the same rating, he'd run the risk of destroying the relay as well.

Yeah Dukes, that wiring pic has been around for quite a while. I first saw it on a Jeep forum probably four or five years ago. I use it to show people all the time.

 

Why not run a pair of HID's instead? Cooler, Brighter, and they draw way less power.

 

so took it apart and you can compare the wires that were inside , i'd guess 16ga- 18? inside, those are 12 gauge rolls next to it, well if you can convert 0.75mm2 < Thats what it says on the wire that was inside, anyways gonna wire up the inside with 12ga? along with everything else? Have about 60 bucks total everything you see if this works out so i guess 60 bucks aint to bad for a pair of budget 130watters egh?lol...have you guys seen those KC Pod Lights on thier site they look cool. http://www.kchilites.com/