KC lights question?

[idaxj97]

I have 4 KC daylighters 100W and i am wanting to run all 4 on the same switch to minamize switchs and wires i am running a stock jeep cherokee alternator do you think the alt. iis big enough to power them without killing it? the reason for running the kc's is because i already had them from my previous rig and money is tight, later on down the road i do plan on getting lightforce :wings: thanks for any and all help.

 

[ntsqd]

4 X 100W = 400W
400/12 Volts = 33 Amps

Very few switches can handle that much current. The typical Bosch style relays are rated for 30 Amps. So you're looking at either two relays or finding one of the Bosch style relays that are rated for 40 Amps.

What is your alternator's rated output?

 

[KG6BWS]

yes you can. as long as youve got the lights running on relays the power going thru the switch itself is hardly anything. on my old 4x ranger i had 8 kc's going thru 1 switch. just make sure the relays are all wired properly. you want to use 1 relay per pair of lights. right now ive got 6 hella 500s on 1 switch with 100 watt bulbs.

another thing you could do, although i dont have a wiring diagram for it, is use a 3rd relay to supply power to the lights relays. basically you would be using the in cab switch to turn on relay 1, which would act like another "switch" and supply power to relays 2 and 3. that would make it even safer, with even less power running thru the in cab switch. thats what im planning on doing when i get around to rewiring my auxiliary stuff.

the key is relays.

and yes your alt. should be big enough as long as you dont let it sit around for a long time at an idle. with my stock 60 amp alt i was able to run all of my lights but if i parked it and left all the lights on i noticed a drop in voltage on my scan guage.

 

[idaxj97]

ok now for the dumbest question of all time. what is a relay and what does it look like? im sorry for such a question but ive never had to use one.

 

[madizell]

Relays are usually small black cubes with, commonly, 5 pin connections. The function of a relay is that of an electrical switch, opened and closed by an electromagnet. Your dash switch supplies power at low amperage for the electromagnet, which in turn closes the main high-amp switch. This puts the hard work inside the relay where the contacts are large and rated to do heavy work, and leaves the dash switch to handle only the small amperage needed to run the magnet. Trying to run 30 amps through a dash switch has lots of down-sides, not the least of which is running 30 amps or more inside the cabin and behind the dash where you can't get to it if it catches fire.

Two of the connections on the relay are for power and ground for the switching circuit from the dash switch (these activate the magnet and close the switched circuit), and two are for power in/power out to whatever you are trying to run, such as your lights. If provided with a 5th pin, that one is power out opposite of the switched power out. That is, the 5th pin is constant hot when the magnet is not powered, and goes dead in favor of the other power out when the magnet is active. Like a diverter switch. Power will be available to either one or the other power out, but not both at the same time. I have yet to come up with real a use for the 5th pin, so I blank off the wire on the harness. The 5th wire would allow you a work-around on the relay in the event of relay or switch failure because it is constantly hot, so in the event of a failure, you could swap the non-working switched power out for the constant hot power out, and power your lights or fan or whatever, but I wouldn't worry about it for now.

So, think of a relay as a remote controlled switch.

Side note: I would use one relay per pair of lights, but would not use a relay to fire up the other two relays. Instead, I would run the switch wire from the dash to both relays and let them share the same source, just as I would allow the two relays to share the same high-amp power source. The amp draw on a relay magnet is low and running two relays on the same switch won't overload the switch. Using two or more relays in series will work, but makes diagnostics a pain if something goes wrong. It is more complicated than it needs to be. So I would not use a relay to trigger other relays.

 

[idaxj97]

ohhhhhh. gotcha. and i take it that the relays can be bought from any auto parts store right.

 

[tomak]

ohhhhhh. gotcha. and i take it that the relays can be bought from any auto parts store right.

In general yes. You can also try hardware stores such as ACE (just make sure you're getting a 12V rated ).

On the web: 40 Amp relay

 

[ChrisInVT]

4 X 100W = 400W
400/12 Volts = 33 Amps

Very few switches can handle that much current. The typical Bosch style relays are rated for 30 Amps. So you're looking at either two relays or finding one of the Bosch style relays that are rated for 40 Amps.

What is your alternator's rated output?

I know I'm a bit late, but shouldn't you rate them at 14.4v? Although, It is safer to rate them at 12v since it'll have more of an amperage draw at a lower voltage

 

[92 red cummins]

I am runing 4 to 1 switch no problems.

 

[ntsqd]

I know I'm a bit late, but shouldn't you rate them at 14.4v? Although, It is safer to rate them at 12v since it'll have more of an amperage draw at a lower voltage

I use 12VDC for the reason that you state.

Something to think about is if you are over-driving an electrical component and it works, for how long will it work? With a high quality part it might work for quite some time, but those ratings aren't done just for the fun of it. Over-driving something when you know the risks is one thing, doing so blindly is asking for trouble at the least opportune moment.

 

[Borrego60]

kc lights

I run a 30amp relay for each light, Controlled by 1 switch. I run the daylighters which are 150 watt lights 385,000cdp each. If you have a 6" housing you can buy the sealed beam 4049 and have the same light with out the KC on the glass. I would go to the assessory section of the auto parts store and find a relay kit and it should have all the wiring for the lights battery ect.Try looking at this on ebay 370220175427. I also run a motorola dek system for running all my electrical toys,off road lights,compressor,rock lights ect. The switchs go up to 3 amps but running it with relays you can run just about anything,same system fire trucks have to run emergency lights strobes ect. Deks have 6 switches and two momentary switches and are back lighted.ebay item # 360168866588.

 

[pete.wilson]

Hey

I would strongly recommend you running each pair of lights through a relay (2 relays needed) and then also going with a heavier gauge wire from the battery to the relays if your using only a single power wire instead of two. Also, if it's drawing over 30 amps, your pushing your alternator since you may have your headlights on, stereo, tail-lights, etc. and any other electrical devices. I would think at least something in the 100watt range for an alternator and it's a good idea if you are planning an extended run time with these lights, to consider running a second battery also. Don't go with just a switch, always use a relay and/or at the very least fuse each power line if you do run just the switch (30amp min. and then use 2 switches for each pair of lights).

Pete Wilson

 

[roostercruiser]

im running 3 x100 w and 2x 50w with no problem on one switch. also you to run in line fuses to everything for protection.