14" Light Bar XM-L2 Mod

Hello all,
Fist post here on cpf, I have been trolling this site for the past few years but its finally time for me to ask some questions.

So I have a 14" amazon light bar on my jeep, its made by a decent company "opt7" (I'll provide a link to the bar below). It uses XB-D LED's making 259 lumens each. Its OK but it could be much brighter, so my plan is to pull out the stock pcb with 24 xb-d's with integrated drivers, and install 24 Cree CM-L2's with external drivers.

I spent the last few days searching the forums but didn't find much on people modifying light bars.

So the questions i have are..

What would be the best configuration? My plan was to run 3 emitters wired in series to 8 separate drivers(3A@9ish volts).. This is just because from my searching i haven't seen many people run more than 3 LEDs per driver. So could i run more XM-l2's per string? if so what would be the best driver? Im willing to dish out the cash for 8 drivers if that's the right way to do it, but i haven't found many big drivers that are well built and automotive rated. Could i just buy cheap ebay drivers and install some diodes/caps before to help clean up any spikes/noise? Also since I don't see myself fitting the drivers inside the bar i plan on running a positive wire from each string out to a project box, and sharing one single negative wire in the bar (I'm assuming that will be ok?).

Also im not to worried about heat dissipation, i wont be using this bar unless im driving, and it never gets left on for more than 5 minutes at a time regardless.

What is a good fast shipping site to buy XM-L2's? there is a bunch on amazon sold by "SpecialFire" is this seller trustworthy? i just am afraid of buying 24 bogus emitters.
These..
http://www.amazon.com/dp/B00HTUV70Q/?tag=cpf0b6-20

Some pics.

Here im just trying to illustrate what i mean by powering the emitters externally.








I Also i don't think ill need a boosting drivers, i have two 980CCA AGM batteries that never drop below 12V.


Heres the original bar link
http://www.amazon.com/dp/B00KJ189EE/?tag=cpf0b6-20

Ill be posting pics of the build as it nears completion.


Also to the mods, since this is a "modification" i figure this is the appropriate forum. If its not, my bad, feel free to move it

Thanks in advance for any information

Hi zauggerr, welcome to CPF :welcome:

Thats a nice light bar your going to modify, and there is a Homemade and Modified Discussion section that this thread would be better suited in the Moderators will probably move it.

I hope there is a good heat path under the LED/Driver PCB that you can mount stars onto once you remove the existing board
24 XM-L2 at 3 amp is 240 watts! 24,000 lumens!
Thats going to get hot even with air flow maybe fab up some air scoops for the sides of the bar to really duct air across it

I'd definately use a 22ga multi-stranded wire for carrying the current and flexibility.
You'll also want to limit the distance between the driver and LED as much as possible, I can't remember exactly but I believe resistance in the wire run can affect driver output.
A buck dc-dc driver will probably work you'll be about 10vF on a string of 3 good luck

Did you know there is a 6v MT-G2 2000+ lms at 3A
Bigger LED size so you'd need to change the reflectors but could run direct drive with 2 in series and 12 might be enough

Can't wait to see what you come up with

nein166,
Thanks for the response. I think the housing itself will be well suited for 240Watts of heat, It is like any standard led bar and the entire back is a row of 14 fins from top to bottom. As I mentioned it wont get much prolonged use, only when driving and I have never kept mine on for more than 5 minutes at a time. Regardless I do like your side scoop idea, I might stop by my machinist friends house and see what he could do, hes pretty good with a bridgeport. The inside is all aluminum and is apart of the heatsink, so i was going to secure the emitters/stars directly on with plenty of good thermal paste in-between. I have a ton of good 18ga wire, i was planning on using that. Is there a chart i could use to see how long i could make runs to the drivers?

I figured a Buck driver would be my best bet. I found a couple on amazon that seem decent, i would love if someone would take a look and give me a cpf opinion on them, like i said im willing to pay extra to do this right.

My next question is, does an LED emitter only only draw current that they require? or will they pull more then 3A each and pop if i use a 12A driver for 3 in series? If that so, could i use a 12A driver and run 4 xm-l2 in series? Because I found a decent driver on amazon that has great reviews(it just doesnt say anything about adjustable current), i know its 12A max, but i will be installing over sized heat sinks on the drivers.
http://www.amazon.com/dp/B00BYRJXGA/?tag=cpf0b6-20

Ive seen the MT-G2's, i like them, but i want to stick the the xml's, it will just be less of a headache to use the provided reflectors.

Heres a pic to show the inside ill be securing the stars too.


Thanks!

That DROK driver is constant voltage. It will vary the current to keep the voltage the same, LEDs don't want that.
Look for a constant current driver, I don't know of one big enough for your application. You could use many drivers
Check out TaskLED.com hyperbucks aren't cheap but the products are top notch

nein166 said:

hyperbucks aren't cheap but the products are top notch

Click to expand...

Oops sadly they are discontinued

Look into the hyperboost its technical section says under Output Power: For 12v, 6A input it can drive 20v worth of XM-L2 at 3A and that looks like 6 LEDs if you believe Crees datasheet claim of 3.3vf at 3A

I was looking at the hyperboost and did my math wrong, If i can put 6 XM-L2's onto one driver its well worth paying the 40$ for the hyperboost. I noticed with those drivers there is no Mosfet's to attach cooling on, does it only need a heat sink against the back side? If you really think the Hyperboost is the way to go then i will purchase 4 immediately.

Just ordered the 24 XM-L2's from Rapidled.com! So it begins..

Will a small heatsink with fan be enough to keep the hyperboost cool? like this.
http://www.amazon.com/dp/B00H8QRFU2/?tag=cpf0b6-20


Heres the inside of the bar, just show the side that will be taking the thermal load. (ignore the arrows)


And heres the bar in action before I took it apart. the 50" bar is also a opt7 C2.

The entire back side of the hyperboost gets thermal transfer double-sided taped to a heatsink (Bond-Ply 100 included)
I'd look for a metal box to put them inside, weather protection and heatsinking, maybe consider potting the boards inside
Looks like that unit will catch the brunt of well everything

I know George of TaskLED used to be around CPF and he has a Forum of his own for more info on these drivers

nein166 said:

The entire back side of the hyperboost gets thermal transfer double-sided taped to a heatsink (Bond-Ply 100 included)
I'd look for a metal box to put them inside, weather protection and heatsinking, maybe consider potting the boards inside
Looks like that unit will catch the brunt of well everything

I know George of TaskLED used to be around CPF and he has a Forum of his own for more info on these drivers

Click to expand...

I sent George an email, asking if he thinks that will be a well sutied driver for this application, and from expierience what he reccomends for added protection such as capacitors etc.

Bought a bunch of items for the driver enclosure.
Firstly the enclosure itself, its aluminum and 7x4x3.
http://www.amazon.com/gp/product/B005T7RPFC/?tag=cpf0b6-20

I then purchased a pack of 4x4 copper plates, im going to place the thickest plate([FONT=verdana, arial, helvetica, sans-serif].0647") on the inside of the bottom of the box. I purchased two packs of Artic Silver thermal adhesive to secure it to the bottom.[/FONT]

[FONT=verdana, arial, helvetica, sans-serif]On the outside of the same side the copper plate is against im going to mount a AMD 939 socket heatsink bracket, the two screws used to secure it down will go through the project box and help secure the copper plate.[/FONT]
[FONT=verdana, arial, helvetica, sans-serif]Socket 939 bracket[/FONT]
http://www.amazon.com/gp/product/B00AAXYPJE/?tag=cpf0b6-20

[FONT=verdana, arial, helvetica, sans-serif]I will then purchased a cheap but decent CPU fan to be mounted on that opposing external side.
[/FONT]http://www.amazon.com/gp/product/B004DR2TDC/?tag=cpf0b6-20

Still concerned about heat i purchased a screaming 119CFM case fan to replace the slow fan on the new 939 heatsink i just purchased.
http://www.amazon.com/dp/B000234VZU/?tag=cpf0b6-20

I also purchased FOUR 55mm GPU fan/heatsinks, the plan is to mount 2 on the top cap ontop, and two on the opposing internal side of the cap. directly on top of eachcother, with plenty of thermal paste in-between of course. hopefully that will keep the ambient temperature inside the box a little cooler.

So with all of that I'm hoping the 4 Hyperboosts adhered to the thick copper plate will stay plenty cool.

I purchased two Digital temperature gauges with probes, I'm going to use thermal adhesive to place on probe right against a XM-L2 star inside the bar. and another probe right in-between the four drivers inside the enclosure.

The main heat sink I purchased states it will cool a [FONT=Arial, sans-serif]AMD Phenom II X6 at 3.3ghz... which i feel like is WAY more heat than 4 of these drivers will ever produce, on top of that the included fan is probably only 30cfm, and i will be moving 119cfm over the same heat sink.

And I was about order thermal pads for the emitters, but from searching i discovered that thermal adhesive will do a much better job at transferring the heat. so i will be securing the emitters with Artic Silver thermal adhesive.

[/FONT]Any suggestions?

Thanks!

There are some threads about lightbars in the Automotive sub-forum in the Transportation Lighting forum. You might want to check them out.

PM sent.

Most of the components come in Wednesday

Last night I ordered a pack of 20A Diodes that im going to put infront of the drivers and other small electrical components that im using for this project.
Although im having trouble finding the right TVS diode i will need. I found this..

http://www.amazon.com/gp/product/B005T58RXS/?tag=cpf0b6-20

It states the "clamping voltage" is 25.2v, but its operating voltage is [FONT=verdana, arial, helvetica, sans-serif]15.3V. From what i understand the clamping voltage is when it starts directing voltage to ground, and considering my batteries never go above 14.8 volts when charging i should probably find a suppressor that has around a 15v clamping voltage. Does anyone know a site where i could find these and order just five of these?[/FONT]

[FONT=verdana, arial, helvetica, sans-serif]Im also considering installing a liquid cooling loop in the bar itself, it would be a 1/4" copper pipe around the inside perimeter of the bar, with plenty of thermal adhesive ensuring good thermal contact throughout the bar. The cooling loop would go to a small CPU cooling radiator, BUT before it passes through the light, it would then pass through a CPU cooling block that has a 10A 120Watt+ TEC cooler. I already have the cooler and the water block so I'm going to run some tests and see if a single 120Watt TEC is enough to actually provide any benefit to cooling 3.6L/min of water. I figure the loop of cold water could have some real benefit to the 240Watts of LED's in this 14" bar... Thoughts?

I will also mention, I spent some time searching around at other LED bar posts on CPF and noticed people take illegal lights very seriously (like they should). I want to state that I understand that my light bars are illegal for on-road use, and they are ONLY USED for off road purposes. I am lucky enough to have parents that own 43 acres in a Granby CT, I am always wheeling in the fields and woods where these lights get plenty of action. I have covers for these lights and they get used whenever I know I'm leaving town. Being a competitive pistol shooter I am close friends with a lot of LEO's, I have asked many of them about the laws for having the lights mounted/off when I'm on roads, they have always states that as long as the lights are not turned on while driving that it is legal, and that in CT they are not aware of any laws that require you to keep them covered. Knowing that LEO's are far from perfect i did my research. this is what i found.

"[/FONT]Sec. 14-96o. Spot lamps. Fog lamps. Auxiliary passing lamps. Auxiliary driving lamps. (a) Any motor vehicle may be equipped with not more than two spot lamps and every lighted spot lamp shall be so aimed and used that no part of the high-intensity portion of the beam will strike the windshield, or any windows, mirror or occupant of another vehicle in use.

(b) Any motor vehicle may be equipped with not more than two fog lamps mounted on the front at a height not less than twelve inches nor more than thirty inches above the level surface upon which the vehicle stands and so aimed that, when the vehicle is not loaded, none of the high intensity portion of the light to the left of the center of the vehicle shall, at a distance of twenty-five feet ahead, project higher than a level of four inches below the level of the center of the lamp from which it comes.

(c) Any motor vehicle may be equipped with not more than two auxiliary passing lamps mounted on the front at a height not less than twenty-four inches nor more than forty-two inches above the level surface upon which the vehicle stands. The provisions of section 14-96t shall apply to any combination of head lamps and auxiliary passing lamps.

(d) Any motor vehicle may be equipped with not more than two auxiliary driving lamps mounted on the front at a height not less than sixteen inches nor more than forty-two inches above the level surface upon which the vehicle stands. The provisions of section 14-96t shall apply to any combination of head lamps and auxiliary driving lamps.

(e) Operating a motor vehicle with lamps which do not conform to the provisions of this section shall be an infraction."

"(b) Whenever a motor vehicle equipped with head lamps as herein required is also equipped with any auxiliary lamps or a spot lamp or any other lamp on the front thereof projecting a beam of intensity greater than three hundred candlepower, not more than a total of four of any such lamps on the front of a vehicle shall be lighted at any one time when upon a highway."

"Sec. 14-96z. Intensity of certain lamps. Location of red light. (a) During the times specified in subsection (a) of section 14-96a, any lighted lamp or illuminating device upon a motor vehicle, other than head lamps, spot lamps, auxiliary lamps, flashing turn signals, emergency vehicle warning lamps and school bus warning lamps, which projects a beam of light of an intensity greater than three hundred candlepower shall be so directed that no part of the high intensity portion of the beam will strike the level of the roadway on which the vehicle stands at a distance of more than seventy-five feet from the vehicle."

" (6) "Auxiliary driving lamp" means an additional lighting device on a motor vehicle used primarily to supplement the general illumination in front of a motor vehicle provided by the motor vehicle's head lamps;"

So im trying to interpret this, because it would be handy to print this out and have it in my car if i come across an officer having a bad day.. But from what i understand, as long as I don't have more than 2 Aux lights, they are at the proper height from the ground, and they are pointing at the ground, it is legal to be mounted on the vehicle? (of course STILL not to be used on road, just seeing what the laws are to have them installed on the vehicle).

All of this was found at http://www.cga.ct.gov/2006/sup/Chap246.htm

I didn't find anything about needing covers.

Looks like a great project. I looked at the Amazon link and if that entire back piece of the enclosure is solid aluminum then you have nothing to worry about with heat provided that the light is only on for 5 minutes at a time. Forget the water cooling. In NE USA you shouldn't need anything like that for night time temperatures. Even if it does get a little hot once or twice, those LEDs are rated for 100,000 or 70,000 hours (don't know exactly because I have been out of LEDs for a little bit) to 70% output. Even if you shorten the lifespan by 20,000 hours, you will never degrade the bar to the point where you will notice it.

It is a luxury for you in this case to neglect a bunch of thermal problems because of the very short bursts this will be used for.