High power LED's

[matt and tracy]

Has anyone tried building a high power led light? Any success stories?

[lynxvs]

I'm almost afraid to reply because this seems to be such a sore subject but I built a 24" LED light that seems to work pretty good. I documented some of the build on my website and posted some of it on this forum. I'm awaiting a PAR sensor which should arrive next week (Took a month to get) to make some PAR measurements. If your planning to build one expect to spend at least $800.00 not including any tools you need. I can help with some of the details. I plan on posting the all of the plans that I have on the website soon.




http://reefcentral.com/gallery/data/500/200771Pendant.jpg

http://reefcentral.com/gallery/data/500/200771lens_install4.JPG

http://reefcentral.com/gallery/data/500/200771Fans.jpg

http://reefcentral.com/gallery/data/500/200771All_on.jpg

http://reefcentral.com/gallery/data/500/200771boards.JPG

www.photiczoneled.com (http://www.photiczoneled.com)

[lynxvs]

Here are a few more pics.... One before the LED light and one after three months


BEFORE
http://reefcentral.com/gallery/data/500/200771Before.jpg

AFTER
http://reefcentral.com/gallery/data/500/200771Light_Tank3.jpg

[hpglow]

I made a custom built LED bar to put in with my T5s to provide shimmer. When I borrowed my local clubs par meeter I found that the 40W LED bar put out close to the same amount of light as one 80W T5. Keep in mind however the 80W lamp is 60" long and puts out fairly uniform light across the tube and the LED bar that I made is only 36" with 12LEDs so the intensity is far greater in the center of the bar then on the edges. Here is a some pics from the tank that has that LED bar on it...
Http://www.thescmas.com/forums/gallery/files/2/8/1/aog.jpg
Http://www.thescmas.com/forums/gallery/files/2/8/1/parreadings2.jpg
The top numbers were all taken 1" above water under the light grouping indicated on the left, the rest were taken at their respective depths.

I am running 5 T5s. The LEDs are Cree XR-E Q5 bin and they are driven by a Advance ballast co Xitanium 1740ma driver. My lamp setup is ATI True Actinic, ATI Aquablue Special, ATI Procolor, 12 LED bar, ATI Blue+, ATI Blue+.

[lynxvs]

hpglow
It's nice to see some PAR readings from an LED light. Do you have pics of the light bar that you made? Are you using any kind of lens on the LED? Are you thinking of expanding the 36" light bar to 60"?

[matt and tracy]

Why is this a sore subject? I would like to see this lighting take off. I plan to build one though the cost is a huge factor. I don't want to start purchasing till I know exactly what I'm doing.
Thanks for the great pics and information.

[lynxvs]

I don't know why..... it's just new..
You’re smart in waiting to build something till you have more info..
Although there isn't much information on building your own LED Aquarium light as you can see by the replies to this thread...

[jjoos99]

I too would like to see what the led light bar looks like. what kindof costs are involved? I run t-5s and would love to see some shimmer in my tank. I didnt know how strong and how many led it would take to get through the t-5 lighting.
jeff

[areze]

Cree XREs are argueably the wisest choice for materials. other options you may want to pursue are the luxeon rebel or luxeon K2. most would say they are slightly less economical though.

past that, the big hurdles are cooling, which you'll generally want to find the biggest aluminum finned heatsink you can get your hands on, and a PC fan or 2. not sure what the guy above had for heatsink, but you can see he's got the fans on there.

then comes PSU, bottom line truth is your going to need to get creative here. any prebuilt driver puck is going to break the bank for the kind of power your going to need. Bridge Rectifier could be an option to just convert from AC to DC, no experience with them though, alternative is a PC Power supply, provides clean DC power for you, fairly efficient, well priced. unfortunatly some of it will go to waste as we dont have much use for the 3.3v rail, and the 5v rail probably isnt going to apply either. all the same, it will have a good chunk of amps available on the 12v rail, which will go a long way.

[Michael]

yep it can be a sore subject, too many high claims, however im impressed with the 2 builds on this thread, i think lynxvs and hpglow have done a good job, especially the par figures, they look a lot more practicable, i have some leds and par levels of 200 at the surface to about 45-50 at sand level are all im getting, but theres definate progree with leds, when better made leds become available and afford able i will convert fully, good job guys

[lynxvs]

I use the Luxeon Rebel LXML-PWC1-0070 Cool white and LXML-PR01-0175 Royal Blue LEDs. The cool white output 70 Lumens at 350 mA and 130 Lumens at 700 mA. The blue produce 175 mW Radiometric Power at 350 mA and 325 at 700 mA. These are not the brightest you can get in the Rebel you can max out the Cool White at 100 Lumens at 350 mA and 180 Lumens at 700 mA and the Royal Blue at 275 mW at 350 mA and 525 at 700 mA. I picked them because they where available at the time. I plan on upgrading my LED array from 50 LEDs to 60 LEDs with an addition of a few Cyan. The good thing about the Rebels is you can use FR4 ( Printed Circuit Board Materal) which is common for PCB fabrication and run at lower current so less heat. The heat sink I use is just a flat 1/8" Aluminium plate. I know this raises eyebrows but I made a few calculations that I posted before:


Here’s how I justify the heat sink size:

Max Junction Temp = 150° C
Power of Single LED = 3.4 Forward Voltage X 700 mA = 2.38 W
Ambient Temp = 70° C ( A SWAG)
Thermal Resistance between Junction – Case (From Data Sheet) = 10° C/W
Thermal Resistance between Junction and PCB (From Rebel application note) = 7° C/W
Total Thermal Resistance = 10 + 7 = 17° C/W
Total Thermal Resistance between Junction and ambient air = (150 – 70)/ 2.38 = 33.61 ° C/W
Thermal resistance between Case and Ambient air = 33.61 – 17 = 16.61 ° C/W

The amount of heat dissipation that can be achieved with a flat plate of aluminum is indicated below.



Using a 3mm plate looks about 20 cm^2 per LED converting to inches is equal to 3.1 in^2 * 50 LEDs = 155 in^2 The plate I am using is 24 X 7.25 = 174 in^2 not sure if you can count both sides of plate as surface area… I also have two cooling fans to help…

I use a single output 24 Volt switching power supply that is rated at 12.5 Amps. I bought it new for $24.00 and installed it in an enclosure.




http://reefcentral.com/gallery/data/500/200771powersupply.JPG



I used a LED IC driver and microprocessor for control of the light.

[lynxvs]

Sorry I forgot to attach the graph for the heat sink.. here it is

http://reefcentral.com/gallery/data/500/200771thermal.gif

[matt and tracy]

Thanks for providing so much information. Very impressive.