70hemicuda

hi guys,
So the story is I hate the dark, and love lights. I want to put as many as I possibly can on the jeep, with out it looking stupid. I had the idea of like 5 on the roof, two in the factory spot and maybe 2 or 4 in front of the grill. I am probably getting the KC daylighters 130W but i was wondering if you guys could point to the right lens type for a maximum flood light effect. Or if you guys have a good mix of all the types together?
thanks

macgyver35

Wow! You really hate the dark!

Couple of things:

You are talking about possibly putting 11 130 watt lights on your rig. If you tried running them all at once, you'd be pulling 1430 watts, or about 120+ amps, which will max out your alternator. Even with a few less lights, you're not leaving a lot of headroom for your alternator to power those and everything else it needs to power. You could get a high power alternator for several hundred dollars, but you're still looking at lots of power, lots of relays, and lots of wiring.

If you want lots of light, pay attention to the lumen rating rather than wattage. Not all halogen lights are the same, and some will produce more lumens at a given wattage.

As a general rule, LED lights will only use about 10%-15% of the power draw for a given amount of lumens over typical halogen bulbs. So, theoretically, you could get the same amount of light you're after with only about 12-15 amps of power draw. This will reduce costs as there will be no need for an high power alternator, and you can use smaller gauge wiring. You may also be able to get away with just using switches on some sets instead of relays; I think anything under 10 amps draw would be fine to run through just a switch. Anything more, use relays.

However, LEDs are expensive; typically 3-6 times the cost of comparably lumen rated halogens. But again, some of these costs will be mitigated with saving on wiring and power supply. Rigid Indusrties is a popular brand of LED light, and ProComp has a line as well.

For a small example, I'm about to recess two 3/4" round LED puck-style lights in my rear bumper. I want them for area lighting when hooking up a trailer at night. They will put out a total of 200 lumens (about as much as (2) 3-D cell Mag lights) but will only pull about 2 watts of power, or about .167 amps. I plan on putting two 10 watt LED lights on the front bumper that will put out 3800 lumens each (comparable to 100 watt halogens). So, total power draw of 20 watts, or only 1.67 amps, instead of 200 watts/16.67 amps.

There are other factors as well that effect how well you "see" the light you use and how effective it is. Color temperature, dispersion or focus, etc. Do some research and learn a bit about light. You'll be glad you did.

Gee oh Dee

^^Jesus.


I would go to Harbor Freight and get some of their off road lights. Cheap, reliable, effective.

98_XJ Sport

I have 2 driving lights and 2 long range KC's. I personally love the driving lights, they make a sorta flat beam more than the direct spot beam.

AoA

4 100w spots on the roof, 2 55w yellow fogs, and 2 100w driving lights did the job and then some, people described it as a "mobile sun"

SeriousOffroad

With that many lights planned for your rig, you might want to consider some upgrades to your battery and alternator as well.

Look into L.E.D.s as well. They offer tremendous output and use a fraction of the current of standard Aux. Lights.

krustyballer16

5 "harbor freight" lights with 130 watt bulbs on roof, 2 KC Daylighter 130 watt long range on the bumper and 130/100 watt headlights. My headlights on dim are usually bright enough but if its really dark and i feel like driving in day light i turn em all on. I can see almost everything perfect 3/4 of a mile ahead of me and the KCs show reflections off signs almost 2 miles away. and my roof lights shine about 40 feet from the ground to the tops of trees. and about 60 feet to the sides. Ive also got two more Daylighters to put on. just havent found a good place for em yet.

AoA

I have lol, 160amp alt, various wire upgrades, and a optima red too. As soon as my snorkel goes on and frees some room up I'm putting in a second deep cycle batt. I have looked into some LED roof bar options, they are epic and look great, but the price keeps my priorities straight hah, gears first!

70hemicuda

im gonna do a battery upgrade very soon but the alternator is another story. with 5 say, 130 watt lights on top be to much for a stock alternator? oh, and thanks macgyver35 for that lesson on lights, that really helped. and those rigs looks great.

Michael952

4 on top and two on the bumper looks the best imo

AoA

As long as you kept the rpm up higher then idle it would survive, a lot of strain on the whole electrical system though, I don't recommend using them for long periods of time let alone at idle :X

70hemicuda

I wouldnt be using them for long at all, just for when its raining or im on a dark side road. that should be find right? and also, what's the best lens type for a wide, flood beam?

TonyXJ

I've never tried to do any calculations on a car system. So it's safe to say we get about 12 volts dc circuit from hooking up to the battery directly? Then everything electrical is put in parallel with what's already in place.

At 12 volts, how many amps can we expect from stock alternators at idle? And how many of those amps can are available to draw without other systems starting to fail?

SeriousOffroad

You'll be lucky to get 40-50 amp at idle.

Watch your gauges and start turning on your fan, radio, interior and exterior lights...

Now imagine adding 2-3 high wattage lights.

An extended idle switch will help, but even at 1000 rpms your alternator is going to struggle.

If you really want that kind of light output...L.E.D.'s.

Now I'll sit back and wait for the harbor freight junkies to chime in.

macgyver35

Different alternators are capable of different amperage at idle. This is affected by the specific brand/model of alternator. Also, vehicle idle RPMs and the size of the alternator pulley in relation to others determine alternator RPMs at a given engine speed.

I'm not sure what any given output is for various models of Cherokee. I do know that on my 98, the FSM calls for a minimum test amperage of 90 amps at an engine speed of 2500 RPM.

I suppose you could spend $25 and get an inductive ammeter from Harbor Freight and see what you get at idle.

I suppose for me, the bigger picture is, does anyone really need 10+ 100-130 watt lights mounted on their rig? It just seems like massive overkill to me.

For those that don't know, lights are frequently rated in watts, which is a measure of power consumption, not light output. Lumens, or Lux, or Candlepower (and all three of those are different kinds of measurements) are measures of light output. Lumens is becoming the most common measurement used. You'll notice that a 60 watt household light bulb has somewhere around 900 lumens printed on the package. You may also notice that a 12 watt compact fluorescent has a similar lumen rating.

And for those that don't know electrical math:

Voltage X Amperage = Watts

so given that, we also can say:

Watts / Volts = Amps or Watts / Amps = Volts

Keep in mind there will be parasitic factors such as voltage drop on long runs, and control circuitry usually results in a loss of efficiency due to resistance and other factors. Figure 3% to 5% on most automotive electrical circuits.

Also know that amperage is what determines wire size, not wattage or voltage. That's why fuses and circuit breakers are rated in amps.

EX: A hair dryer typically has a cord that is 14 gauge wire and it pulls 1800 watts. However, this wattage is delivered on a 110 volt feed, so we only need to send about 16.4 amps through the wire. Now, if we try to pull 1800 watts through on a 12v system ( a big audio amplifier for example), that is an amperage load of 150 amps! You'll need MUCH larger wire to feed that much current through to the amp. Probably 2 gauge wire or so, which would be like that used for jumper cables. Plus, you're maxing out or exceeding your alternator at full amp output.

Think of it like water moving through a straw.

Voltage is the speed (or pressure) of the water flow, and amperage is the volume (current) of water flowing through the straw at any given instant. A given wire size can only handle so much current.

If I need to get 1 gallon of water through the straw in under a minute, I can go two ways. I can increase the speed (voltage) of the water flow through my existing straw. Or, I can keep a low speed (voltage), but use a garden hose (more amperage/higher capacity) instead of a straw.

So, low volumes at high speed or high volumes at low speed can result in the same total output (wattage) over a given instant.

5 amps X 110 volts = 550 watts - (small wire)
45.8 amps x 12 volts = 550 watts - (large wire)

I know you may have to take some time to wrap your head around this if it is new to you.