My New Home Brew Light Bar

[Anonymous Poster]

Now that I can see in the dark, and possibly getting ready for snow blading if we get some in Missouri someday.

Couple of treated 2x4's, some nuts and bolts...
4x 55 watt lights -
Used 2 Trapozodial in the front, 2 floods in the rear.
Ran one 12 gauge wire to the positive lead on the battery, with a 30 amp fuse. From the fuse to the 2 switches (20amp each capable switch) i used 14 gauge wire. Then from the switch to lights, 14 gauge wire.

My Question:
1. Can I run one 12 gauge wire while all 4 lights are on? (this is how its connected now)

2. Is a 30 amp fuse to big? or would a 20 amp be better?

3. Correct me if I'm wrong
I'm thinking these lights pull 55 watts x4 = 220 divided by 12 volts = 18.3 amps

I have a 40 amp alternator, I'm assuming this is ok running the 4 overheads with the 2 front headlights, and rear small red tailights on Rops?

Thanks for responding, If anyone has pictures of there lights setup, please post it ) I'm curious to see what everyone else has done. Thankyou!
John

 

[Anonymous Poster]

Up close...

 

[Anonymous Poster]

Showing the wiring...

 

[Anonymous Poster]

Rear Picture...

 

[Anonymous Poster]

In the dark, from front...

 

[pajoube]

Good job on the light bar. This will really help with the early darkness.
As I look out the window it is snowing very heavy, plowing tonight will be necessary.
PJ

 

[Anonymous Poster]

Hi Picard335,

Just curious...but if you were willing to drill two holes in your ROPS for mounting the light bar...why not just drill four and mount the lights right to the ROPS without the "middle man" so to speak?

My inclination would be to mount the light bar without drilling into the roll bar, using stainless steel hose clamps.

Sure makes me want to put some lights up there on my tractor too.

A fifty watt lamp will pull between 4 and 5 amps. I forget the rating for stranded wire, but 12 guage wire should handle 20 amps. Feel the wire after the lights are on for a while. If it is hot, that is no good. Warm would be OK. MY guess is that if you are using only two of the lamps at a time, it will not even get warm.

Bill in Pgh, PA

 

[Anonymous Poster]

OH...

The fuse is only for protection if something shorts [at least in the practical world]. 20 might be too close if you have all four lights on. A 55 watt lamp pulls about 4.5 amps...your calculations are correct. Battery voltage will likly be higher than 12 volts...so the amps drawn may be a little different that the calculation but not by too much.

I think your use of 12 and 14 gage wire will be fine.

I also have a 40 amp alternator, and the reason I got that option was so I could run four 55 watt lamps like you are and not worry about it. I don't think you will have a problem doing that.

Have fun in the dark! /w3tcompact/icons/grin.gif

Bill in Pgh, PA

 

[Anonymous Poster]

Hi Bill,
Thanks for the helpful info!
I found this site too, it has the table for lenghts and amperage for 12 and 6v applications http://www.rbeelectronics.com/wtable.htm

Looks like I'm right on track for the wire, fuse being used.

The reason I didn't drill 4 holes, cause I thought i may weaken the rops? Sounds silly, but i really didn't want to drill holes at all. I didn't think about the clamps, but I'm afraid they would vibrate around and misadjust over time? Good idea though if only temporary!

The rops had two holes in it from the factory, on the back side, so all i needed was to drill two more in front...
I didn't have any metal, or angle iron/steel, I imagine this would've be a better choice. I'll see how this goes, and if the vibration over time will pull out the wood screws holding the 2x4's.

Hey PJ, did it end up snowing ?

John

 

[pajoube]

Snow ended about an hour ago - we got about 3 inches with the areas only a mile from us getting only 1 inch. Very good moisture.
PJ

 

[theboman]

I'd have to have a helment with heat shield. I'd knock my head all the time and burn my scalp being that close to those lights. John, just how tall are you?

 

[Anonymous Poster]

I highly recommend and use relays for additional lighting and equipment loads!
They are very cheap and will eliminate running the amperage load through the switches.

Just a suggestion -

Use 2 relays, one for each set of lights. I would suggest a 10 ga wire that feeds power to both relays from the 12v source. The 10 ga wire can be protected by either an inline fuse or an auto reset circuit breaker, also very inexpensive.

Run a 16 gauge wire from the 12v source to both switches and again, protect the wire with fuse or circuit breaker.

Run 12 ga wire from each relay to the set of lights it controls.

The net result is that the switches now only need a tiny amount of amperage to energize the relays. When the relays are energized, this closes an internal contact, and allows a direct current flow from the the 12v source, through the 10 ga feed to the relay, then through the 12 ga wire to each light set.

More trouble? yes! However much better than running higher amperage loads through the switches themselves and also results in a little brighter lighting due to less resistance. I do a lot of work on a variety of streetrods and related stuff and this is cheap insurance against meltdowns!

 

[mbsil]

Your wire size and overload protection are fine. You might consider "potting" the switches so they don't corrode as fast.

"Potting" is basically encasing the switches in a non-conductive goo that hardens and keeps out water/moisture.

Or just silicone the hell out of everything except the switch handle.

 

[Anonymous Poster]

Hey John - the lights look nice. What kind are they and where did you get them? Thanks!

Steve