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Unread 02-04-2013, 11:59 PM   #1
Modstock
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Wiring lights without relays.

Anybody wired thier (aux) lights without relays .
Ive been told it can be done if the switch had the right amperage and thicker gauge wire.
My lights are 55w .
Today I called up 4WParts to get a quote for wiring up my 4 lights and they quoted me $550 . Whoah, nevermind I'll do it myself.

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Unread 02-05-2013, 12:05 AM   #2
Jonathanjr1
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You can, but its not a very good idea. the aux lights that came on my jeep did not have a relay they worked but it was not very safe. Spend the extra money on the relay and proper fuses so your jeep wont burn to a crisp.
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Unread 02-05-2013, 07:50 AM   #3
haloperformance
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The hardest part is knowing what on the relay goes where. A quick search and you can find a ton of good color coded wiring diagrams on google. It will show which pin on the relay is ground, which is you switched power, etc. Take some time, get familiar with the diagram, and good luck. Its not as hard as you think. Just seems like it.
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Unread 02-05-2013, 08:33 AM   #4
chriskeenan
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for 550$ the switch and wires better be gold plated or something, that's ridiculous.

Can you wire lights without relays = yes, easily.

Is it the best way = not really.

As long as the switch, fuses, and wire are the right correct size for the amperage draw nothing bad will happen, no smoke, no burnt wires, no jeep self-immolation. Same goes for relays, but they give you much more options for switch (they only have to be rated to ~1amp to trigger the relay, not 30+amps to power the lights) and other options. Like say you only want the lights to work while the ignition is in run/acc, with a relay set up you can tap the switch off the acc circuit and power the lights through the relay strait off the battery. trying to do the same off the acc circuit with out a relay will work but running anything else (like a phone charger) can easily pop fuses, since it only supplies IIRC 15amps max and the lights will draw ~10-8amps per pair.

edit: 4 lights, missed that at first.

Either way wire from the battery to the lights should be 14ga minimum, 12ga or 10ga would give a good safety margin and possibly allow for 100w bulbs in the future. If using a relay the wiring for the switch and coil ground can be as small as 24ga, but the rest will need to be 14ga minimum. Wire gauge will also vary by length, look here for more info http://www.offroaders.com/tech/12-vo...gauge-amps.htm

The formula to figure out amp draw is: Watts = Amps x Volts

Assuming each light is 55w and there are four of them we get 220w total.

Engine running voltage (13.8vdc) gets us 15.942028985507246amps.
Engine off voltage (11.8vdc) gets us 18.64406779661017amps.

Last edited by chriskeenan; 02-05-2013 at 08:40 AM.. Reason: fixed for 4 lights
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Unread 02-05-2013, 10:59 AM   #5
MGrobe
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I wouldn't run wiring for four lights through an in-cab switch. For $550 I am curious, where are the lights being mounted? Or does that total include the lights?
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Unread 02-05-2013, 12:36 PM   #6
RedRyderXJ
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Why do you even want to do it without a relay? They're $6. Go buy one and do it yourself
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Unread 02-05-2013, 12:37 PM   #7
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Fire bad, relay good.

Use relay.

One relay could probably run 4 lights, but you also can run two relays off of one switch. Your choice.





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foglight-relay.jpg  
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Unread 02-05-2013, 01:33 PM   #8
Pats94
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Quote:
Originally Posted by CJ7-Tim View Post
Fire bad, relay good.

Use relay.
Well if it doesn't work out the fire will be enough light to see what the problem is....
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Unread 02-05-2013, 11:00 PM   #9
Modstock
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I was gonna wire em' up thru 2 seperate switches (2 fog lights and 2 spots)
Using the (Amps = watts divided by volts) formula.
110w/12v=9.167 I would need a 10amp switch at least. I'll probably end up using a 15amp switch just in case with fuses after the battery and 14 gauge wire all around.
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Unread 02-06-2013, 07:14 AM   #10
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You can, but that means you will have to run heavy wires in and out of the engine compartment, along with adding suitable switches. There are a number of relay panels to suit every situation, some have associated fuses. Once the first relay is wired the rest are simple.

Regards,

Jim W
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Unread 02-06-2013, 07:32 AM   #11
Project1
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Quote:
Originally Posted by CJ7-Tim View Post
Fire bad, relay good.

Use relay.

One relay could probably run 4 lights, but you also can run two relays off of one switch. Your choice.





.

Ha Thats funny! That really is the truth ....and relays are really easy to work with.
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Unread 02-06-2013, 10:15 AM   #12
RedRyderXJ
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Quote:
Originally Posted by Modstock
I was gonna wire em' up thru 2 seperate switches (2 fog lights and 2 spots)
Using the (Amps = watts divided by volts) formula.
110w/12v=9.167 I would need a 10amp switch at least. I'll probably end up using a 15amp switch just in case with fuses after the battery and 14 gauge wire all around.
Why are you so set on not using relays? Spend the damn $12 on them. It's easy.
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Unread 02-06-2013, 11:22 AM   #13
squirlgod
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Its safer all around and easier on all the components involved. Plus you'll get maximum light output...and I hate to say it, but just man up and spend the extra 20 mins haha do it right the first time...
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Unread 02-10-2013, 05:21 PM   #14
markcap
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Hey Modstock, incorporating relays will be less trouble than installing 15amp switches on/under your dash.

A relay is a switch. But built to flow higher current (amps). When 12v applied to the coil connections (connections 85 & 86 on the relay) the relay switch closes ( #30 & #87) and the current passes thru to your 55w Hella's. Simply run 12vdc 16g wire thru your toggle switch on your dash back to the relay coil 85 & 86. Use connections #30 & #87 for your 14g or 12g wire over to your Hella's. You could use a terminal strip in order to keep the wiring in order.

I installed hella H'4's with relays for low & high beam + fogs on my Jeep using #12g wire. I also did this on my former cars. Doing it this way you can increase your wattage. For example, in the H4 headlight, I can run 80/100watt rather than the 55/60watt standard lamp. When aimed correctly I never get flashed yet I can light up the road better than a new Audi. If you need more help, PM me.
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Unread 02-10-2013, 07:33 PM   #15
AZ Jeff
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Your biggest issue with NOT using relays is finding switches that can take the constant high-current load running through the contacts. Every time that high current passes through the contacts at the moment they make or break connection, you WILL get arcing inside the switch. That trashes the switch pretty quickly.

Most circuits that use high current switches either have massive contacts, and/or a capacitor in parallel to the switch to soak up the transient current pulse that happens when the switch is opened or closed.

Relays have contacts big enough to handle the arcing that happens when they are opened and closed, and thus are immune to this issue.
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