Flood/Spot Light Questions

[John L]

I plan on installing two flood and two spot lights on a bar along the roof line of the front windshield. The purpose is to light up the woods when driving the trails at night. Floods on the corners and spots in the center. The lights themselves are LED so the draw is somewhat minimal. I have installed a fuse box behind the passenger seat that provides power obtained from the radio plug. I also have the accessory plug to the left of the steering wheel (like a cigarette lighter) available.

I have a couple of questions for the electricians in the group:

First is power source: should I take the power from the plug next to the steering wheel or should I hard wire everything directly to the fuse box. While the fuse box is more work, it would be a cleaner install and look better overall. If it makes a difference, please let me know.

Second question pertains to switches. I'd like to wire it so that with one switch I can turn on the flood lights and with a second switch I can turn on the spot lights. I was reading another post about the need for a relay on the headlights because the switch couldn't handle the load. Can I wire my lights (two per switch) directly to the fuse box or do I need some type of relay?

Third, related question, is what type of switch would you reccomend? Should I stick with the EI or SAV replacement pull type switches to keep it somewhat stock or should I look at a couple of rocker switches (or does it make a difference)? They will be handling 24 v so I'm thinking that a light up 12 volt rocker switch wouldn't handle the load; but, I'm not sure.

Thanks for the input. I'll definately take pics of the install and post them here when I get it finished.

John L

[edzz]

How many amps do the lights each draw?

[pcolette]

Here's what I did just to give you some ideas:

The switch panel is from Daystar, their number KJ71030, for a Jeep . http://www.daystarweb.com Available from Amazon. I used a Dremel tool to trim the panel to fit.

IMG_3117.jpg (60.31 KiB) Viewed 4205 times

Daystar also sells the switches but only in 12 volt. The switches are made by Carling Technologies, (http://www.carlingtech.com) part of their Contura line, and are available in 24 volt from their distributors. I found one that was willing to sell me a handful of them (about $9 each) and they are really nice switches though obviously there are many brands and sources out there.

I fabbed together a light bar that works ok but I've seen nicer ones beyond by current welding abilities.

IMG_0276.jpg (68.32 KiB) Viewed 4205 times

The LED lights draw much less than halogen/incandescent/etc. so I don't think you need a relay. I didn't use one and just picked up power from one of the circuit breakers.

Have fun!

[Jim LaGuardia]

Always use relays for load bearing circuits, heavy loads should come from ignition switch power supply side.

[Jimm391730]

Generally, anything under 10A can be controlled directly by a switch without using a relay (relays never hurt, though). I have pairs of 50W halogen floodlights (100W per pair) on a switch and at 24 volts that works out to only 4A; and I also have pairs of 70W halogen driving lights (140W or 5.8A) controlled by a switch. Of course you need a switch that is rated for these currents (double the amperage is good). 12V or 24V is not a problem for the switch unless it is illuminated (probaby by a 12V bulb).

[audiocontr]

Always use relays for load bearing circuits, heavy loads should come from ignition switch power supply side.

Jim, I have 24v heavy duty switches rated at 50 amps. Does the relay rule still apply? I had planned on running 4 hella 24v lights from EI off of it.

[Jimm391730]

Jim, I have 24v heavy duty switches rated at 50 amps. Does the relay rule still apply? I had planned on running 4 hella 24v lights from EI off of it.

In our DC powered trucks, Watts always equals Volts times Amps. I'll assume your lights are 50W each; so two floodlights would be 100W of power. 100W / 24V = ~4 amps. If you have different wattages then just recalculate.

Now the voltage in our trucks varies from 24V (typically) at rest to ~28V when running. To keep things simple, just use 24V and be done with it. If anything this will calculate to slightly higher current (amps) as a worst case.

The difference in arcing within the switch contacts between 12V and 24V is minimal, any switch or relay rated for 12V will work fine in our 24V systems (not the relay coils or illuminated switch lights!) so you don't have to worry about "officially" 24V rated switches.

You do need to consider the maximum current that could be drawn (winches draw HUNDREDS of amps and are not a candidate load for most switches). While incandesent lamps (light bulbs) initially draw 5-10 times their rated current, the duration is very short (small fractions of a second) and I don't worry much about this, either. But it is wise to not try to switch 10A from a 10A rated switch; engineering practice is to always request less of a device than it was designed to handle; this makes things last longer.

[Stekay]

Not familiar with the workings of LED lights, but normal filament headlights are an inductive load and will pull about 5x their rated amperage upon start up do to high resistance when cold.

[John L]

Ed it looks like they will draw only about 2.25 amps (54 watts and 24 volts. it's two lamps that are 27 watts a piece.). Paul, your rig actually looks pretty nice. I like the switch set up and will try and mimic it. Do you find a need for a plate/shield under the lights to reduce glare? Or does your set up work fine?

Thanks again,

John

[edzz]

Ed it looks like they will draw only about 2.25 amps (54 watts and 24 volts. it's two lamps that are 27 watts a piece.).

I agree with Jim that typically you should use a relay for lights; however with L.E.D.s and the low current you require I would likely simply use a switch. I would however think very strongly about using an additional fuse in line. One of the biggest concerns I see with auxiliary lighting is the wire routing and its protection from abrasion. Proper use of shielding tie wraps and grommets are important to prevent shorts. When I received my Pinz I discovered some of the auxiliary wiring installed by a previous owner had had the insulation worn off due to vibration, the only thing preventing the circuit from shorting out was the factory paint.

[John L]

Ed:

Good advise. I'll probably grab the power from a fuse block I installed from the radio connection. I'll run a fused line from that to the switches and lights. I'll also make sure I use grommets and protection where needed. Trying to decide switch locations. On the right hand side of the dash is a possiblity. An overhead mount would be cool; but I'm concerned about it being a secure install. Once I make a decision and get the light bar I'll shoot some pics of the install for you guys to critique.

Thanks for the input.

JL

[pcolette]

John, I've had no problem with glare but I'd guess that would be different with each set of lights. Mine have a flat face so don't seem to project much light downwards or to the side.
Paul