Wiring, switches, relays, and load

[autumnwalker]

Ok - looking at wiring up my flood lights on the front of the truck. I have four lights, each is 55w / 4.5A for a total of 220w / 18A. I would like to wire up all four lights to a single switch so they all come on with the one switch. I'm considering swapping the bulbs to 100w / 8.33A bulbs so that would mean 400w / 33.32A on the circuit.

If I pickup a 35A SPST switch can I wire the four lights right to the switch or should I still use a relay? Math tells me I can just wire straight to the switch - if I shouldn't do this, please explain why. I have attached a beautiful MS Paint drawing of what I am trying to describe.

[autumnwalker]

For reference - this is the switch that I am referring to:

http://www.princessauto.com/pal/en/Switches-And-Indicators/35A-ON-OFF-Toggle-Switch/8172777.p

Also, not in my diagram, but I would put a fuse between the battery and the switch.

[TRUXterra]

RELAY(S)!!! And that is also a loaded question...lol

You do not want that draw running through the cabin un-fused + it's a PITA to run it. Not impossible, but a PITA to be able to do it correctly the first time.

Give me the following details and I'll draft something up for you ;)

switch location

how/where are you running the light wiring (through roof, A pillar, etc.)

distance from the battery to the lights (based on wire routing only)

closest ground you are going to use

voltage output (at the battery) with the engine running

Need all of this to be able to tell you what gauge wire to run, fuse(s) to use, etc.

[BLAZZING-XJ]

I joud run a relay .if not too ..haft the light on one and the rest to the other. u can use one swith to trip bouth relays and if one burns up u dont have to take the dash apart..

allso the relays have a heavery gage wire...

[TRUXterra]

Scott, if you like the "technical" reading, check this thread from another forum. It goes into insane details, however, has all the answers you're looking for.

http://www.thenewx.org/forum/showthread.php?t=37578

I now run a similar set-up in my X and also helped Dave (Xman) install another similar set-up on his X. My set-up was good before, but not expandable. With the addition of a aux fuse panel, I have many options for the future.

Also, I'm ordering a DTDP switch from OTRATTW in the near future. Check out the site here as I get a 10% discount and the switch would be a lot nicer than a post style (if you have an OEM blank available, & it would fit).

http://www.otrattw.com/index.php

Also, you should consider a combo of fog & driving on 2 separate switches. It will allow you to run a trail behind someone with the fogs on vs all 4 driving at the same time. Max coverage this way as well. Or just go "Command" and get an LED bar...lol

[SQRLPWR]

Diggin the drawing....but X3 on relays. 35 amps is a lot of current to be switching without relays, even if the switch can handle it

[TRUXterra]

<50% is the common ratio on aux additions for relays; 20-30% on fuses (as in a 8A draw uses a 10A fuse. 11A draw -> 15A fuse).

Biggest mistake people make is in choosing the correct gauge for the length of the run. Not only does the power voltage reduce over the length or the run, too small of a wire gauge will cause a lot of heat which leads to many problems, the worst of which is a burnt vehicle due to fire due to the protective coating catching fire, not a short. :smiley-char030:

[autumnwalker]

Thanks for all the input guys.

Devin - I will have to take a whole whack of measurements to get that info for you, but from guestimate here we go:

switch location will be in the cabin, on my existing light "panel" (factory) next to the driver's door.

light wiring will be run through the grill / bumper to the lights mounted on the brush guard.

distance from the battery to the lights (based on wire routing only) is approximately 4 feet to the absolute furthest light.

closest ground for the lights would be probably 2 feet from the furthest light. I'm sure I can find some body there to tap a ground into. Alternatively, the battery or block is only 4 ish feet away.

voltage output (at the battery) with the engine running no idea; assuming 13.5, but I would have to measure to be absolutely sure.

[TRUXterra]

This is what I would propose, just need to determine with wire info & fuses based on the distance & location of the components. Note my "ILL Switches" are illuminated with the interior illumination light and purely optional.

[autumnwalker]

Note my "ILL Switches" are illuminated with the interior illumination light and purely optional.

I'm thinking the silver toggle switches due to size (small) and putting an amber led above them to indicate power. I have about 1" x 1" to mount two switches (I want the 4 lights on a single switch and the second switch for a future project).

[autumnwalker]

Planning to mount two switches on the far left of the dash below the rotary knob for the rear wiper.

Alternative mounting location would be to remove OnStar (center stack) and build a panel.

[TRUXterra]

I'm thinking the silver toggle switches due to size (small) and putting an amber led above them to indicate power. I have about 1" x 1" to mount two switches (I want the 4 lights on a single switch and the second switch for a future project).

I was thinking you were going to the roof (based on you post about locating clamps) lol.... Are you considering roof lights still?

[TRUXterra]

We posted at the same time...lol.

Why run 4 fogs vs. 2 n 2? My 85w PIAA's will light up the dark (not like Commands LED mind you), + if I had 2 others at the same position, I really don't think it would make much difference (IMO). Even with my cheaper Hella 500 fogs, they did a really good job on the front bumper.

Now...add 2 driving to the 2 fogs (roof mounted for me), there is nothing to compare to ;) (Command, kiss my butt, we're talking non retina burning light applications here)

If you currently have 2 sets of fogs and are considering adding roof lights, don't have 4 on the front bumper, save the other set for the roof! On night trails, your roof fogs will not get the baseball bat treatment ;)

Another thing to consider for the future Scott is the roof lights (if you install them). Black has the most reflective properties so the glare off of the hood can be annoying. Glare shields are available, but if you washed your H2 less often, you might not need them...

I went with PIAA Crystal ION's as the light output is yellow. Cuts through fog better & I do not get a lot of glare at night on the dark colour of the hood (from the roof lights).

ETA:

I'll draft you something Scott based on the info posted above (Fuses, wire gauge) for 4 lights on a single switch. Are you considering additional lights working on the rack in the future? You must be considering the second switch ;). What are your plans so I can give you a draft to include both?

btw, lack of forward planning is the reason I've completed the electrical installation twice on my X, as I mentioned above. I'd like to save you the hassle and do it right the first time, in consideration of future plans.

[autumnwalker]

Nothing on the roof of the H2.

[TRUXterra]

Here you go

[autumnwalker]

I need two relays for this?

[TRUXterra]

If you want to run 100w (or higher) bulbs, yes..it is highly recommended. 200w/13V (battery high side, will be lower with the engine off, higher with the engine running)= 15.4A, double that and your are almost at the limit of the relay with 2 sets of lights. You can run 4- 55w lights off of a single relay (wiring aside) all day.

4 x 55w / 13v= 16.9A...

4-85w lights is pushing the limits (4 x 85w / 13v) 26.1A

4 x 100w is asking for problems (400w / 13v) 30.8A

See my post above...relay <50% for aux items, fuse @ 20-30% above draw. To support this, have you ever seen a quad set sold with a single relay? Also remember that relays are not a "fail safe" within a circuit, a fuse is.

[autumnwalker]

Thanks Devin. So why the 15A fuses after the relays?

[SQRLPWR]

because you wouldn't want a 55A * 13V short not to blow the main fuse...well unless you want an impromtu camp fire

having 15A fuse will ensure any problems will pop the fuse

[TRUXterra]

lol, they should be in front. I started to draw a set up using a fuse block, thinking you were putting lights on the roof as well. Stepped away, read your post, and forgot how I started it.

Here is what you want for running more than 55w bulbs. If you keep the 55w, you can daisy chain the lights on a single circuit, but you'd want to use 10-12g

[autumnwalker]

Thanks - I appreciate the help and it has made it clear for me. I have all the gear I need except for the LED and the switch. I will go switch shopping soon :)

[autumnwalker]

Actually - one more question: does it matter if I run everything to a common ground (i.e. the lights and the relays)?

[autumnwalker]

I think I will use a fuse block, but it is pretty simple to modify your diagram to accept one such as this:

http://www.princessauto.com/pal/en/Fuses-And-Breakers/6-Position-Fuse-and-Circuit-Panel/8138224.p

[Lil'monster]

Save yourself some headache and go to the binacle on purcellscove rd to get your fuse block the ones from pa are crap (ask me later) you will pay more but they are marine grade I think I paid like $40 for a 6 fuse block but it also has a ground buss bar

[autumnwalker]

Save yourself some headache and go to the binacle on purcellscove rd to get your fuse block the ones from pa are crap (ask me later) you will pay more but they are marine grade I think I paid like $40 for a 6 fuse block but it also has a ground buss bar

Thanks Clarence! Will do. I would like to do a clean install.