LED lighting

[bdejong]

Here is some more information for those of you who are interested.

These are XLamp LEDs from the company I work for, Cree. They are high power, high efficiency, cool white LED's. I am currently using 20 of them driven at only 350ma, the low end of their spec. I plan on testing them at higher driver currents, but for now I am starting at the low end.

I just added 10 of the Blue version to raise the Color Temp, which it did on fantastic fashion. I added a switch so that I could turn them on and off. I have asked people to tell me which version they like the best and all of them like the added Blue.

http://www.allelectronics.com/spec/LED-112.pdf

I will say this, its not really that hard to build. The hardest part would be the mounting of the LED's. They have to be Reflow soldered and the substrate is the key to managing the thermal dispersion of the parts. Other than that I am using simple off the shelf constant current drivers.

Here is the LED already mounted on a thermal substrate.
1 WATT WHITE ULTRA-ULTRA BRIGHT LED | All Electronics Corp - Parts, Supplies and Components

Here is the driver that I am using (3 of them)
M&m International

Now all you need is a housing, you could convert a standard tube housing with some added heat sinking, a little work, and some money. But hey, for the heat reduction, power reduction and best of all you will never have to buy another bulb again, oh yeah and no big metal lights hanging from the ceiling.

[jhnrb]

14000k seems to be a popular reef spectrum these days and a lot of frag growers use 20000k. hope this helps. The blue end i.e. atinic is at 420 nm but not lower. sounds like you are getting it dialed in. Do keep us posted on your progress and if it works out for you, how many orders can you handle at a time, or, how many testing sites do you want. this is great stuff. stay the course.

[bdejong]

I most definitely will keep everyone informed. I am a firm believer in the free spread of knowledge. While there are no plans of going into the building business (yet, legal concerns ect), I hope to provide enough information so that anyone who wants to can build one on their own thus freeing me from the liability.

Like I stated above, if all you want is the basic light its no that hard to do. While I make to guarantee as to the durability of the LED drivers, the LEDs will last. Proper thermal management is the hardest part.

What I do not know is the PAR value for this light. Nothing we have in our lab is setup to make that kind of measurement. So, if someone knows where I can borrow one from let me know.

I have a few more tweaks to do then I plan on making a final assembly. I am also going to borrow some lamps from my LFS (he wants me to give him spectral measurements for his bulbs, so its a good opportunity to compare).

I will keep a log of the measurements that I can do (spectral, total light, percentage by wavelength and temperature).

Thanks for all the information and get ready to make your own.

[bjohanson1234]

how is the project going?

Brian

[bdejong]

Its going good, from what I can tell I have the right balance for my take as it sits right now. Once the tank gets settled I will start adding corals.

I have not had any trouble yet with heat and all I have had to do is keep the front lexan screen on the fixture clean. I am just waiting until my tank is ready for some coral life. I hate waiting but its necessary. For now I have been trying to get some time invested in a new controller and power source. I want to be able to control the brightness,moonlights and the color temperature. Things like work and family stuff keep getting in the way....

[bjohanson1234]

sounds good
I know how it is about work and family stuff
but remember without work you wouldnt be able to pay for it and without family, you wouldnt be able to share it so you need both

Brian

[bdejong]

Update:

Upgraded the current source for the LED's. I am now driving them at close to 600ma each and I gained enough light output to only have to run one of the lighting units. The temperature increased in the fixture but there is still minimal heat radiated to the water.

[bdejong]

Update: 03/27/2007

The guy that I bought the tank from dropped off a nice coralife aqualight lunar plus that was supposed to go with the tank. I tried it out last night and was not impressed. the LED lights are much brighter and have a higher color temperature than the Coralife unit and the many fans on the corallife are somewhat anoying.

the good news is that the housing is the perfect candidate for a retro-fit of LED's. I like the nice black anodized finish and from what I can tell I chould be able to mount hte existing current source and LED strips in the space currently occupied by the tubes and control circitry.

I will keep the two blue moon leds in place since they are already there and function well. I hope to dig into it tommorow and maybe even have it finished by the end of the week. I think I will tie the fans to a temperature control circuit so that they only turn on when needed and if I get fancy I may even speed goven them(future plans). For now I am going to disconnect them and see how it goes.

What does this all mean for you? Well I have seen these lights in the basic form for around 40-50 with just a basic bulb, since the bulb is going to go anyways, its a cheap metal housing that should provide good heatsinking for the LEDs. Get the housing and a few LEDs and you can retro-fit a lamp of your own.

I will try to do a better job of documenting the retro-fot so that you can try it yourself if you feel up to it.

[jhnrb]

I am very much interested in your project. I have three coralife mh pendants 14" long each. When you get to where you need to be I would be very interested in the specs to purchase the bulbs, ballasts, . i do want to be around 14000k on the overall spectrum. keep us posted. thanks for the update.

[bdejong]

Well I have to say that I am not very impressed with the construction of the Coralife unit.Once I removed the end caps and the reflector assembly I found out where they "Stuffed" the balasts. This unit used two compact bulbs so it had two balasts. While one of the was secured down to the metal housing the second was just floating around in the housing. It was held in place with double sided sticky tape.

Before you say it, yes its designed that way. There is no way to fit them both in there without mounting the second one in this manner. Because of the heat generated by the bulbs and the balasts the tape had given away so it was just flopping around in there.

The air path for the fans was a joke, they sandwiched the transformers for the fans and the moon light LED's transformer and the fan transformer, the air path was very restricted. Its no wonder tis unit ran hot as a pancake.

I have the main reflector out and will bring it into work tommorow to mount the LEDs. Best part is that the channel that used to house the balasts is a perfect fit for the current driver that I am using for the LED's. I can fit both of the current drivers in the space that one of the old balasts used to occupy. I am also going to look for a quieter fan, if I can run them at half speed and get ones that are whisper wuiet it should help remove some of the heat from the drivers.

Whew...thats all for now. Onward and upward.