nstiesi
08/17/2012, 06:51 AM
I have been posting all this in my local forum, so here is a copy and paste so far:
Sorry, not done yet, but I've read so many of these threads here lately that I wanted to throw my hat in. Now, I realized rather late in the game that I didn't bother documenting the build that much until now.
It has been a slow, over engineered garage build. The mechanical engineer in me came out, and though I work for an LED light manufacturer with a full machine shop, I wanted to challenge myself to make something without using my professional resources (mainly because it is hard to get machine time in between production), and I hate asking for favors. In the end, I want to remove my canopy all together, so I wanted something that would look attractive hanging as a pendant.
As for the LEDs, after MUCH consideration, I choose against the new trend of the multichips. The industry I work in uses multichips exclusively for high power lighting, and after my first few months here, I was very excited about the idea of using multichips, and was (and still am, to a point), convinced that they are the future of aquarium lighting. We use the most powerful and efficient multichips in the world, but they proved hard to come by, lacking optic choices, and arent currently available in correct spectra.
So, why did I choose against the "aquarium" multichips:
1) China......nuff said. I am skeptical as to their quality. The lack of useful detail on their spec sheet alone was enough to give me pause. I found the driving current data, thermal limits, and lack of spectral definition worrysome.
2) Lack of optic choices
3) Concentration of heat over small area. Wanting to get heat away from the tank, build something attractive, and build something WITHOUT FANS (that was a big driving factor in my build, my tank is kinda loud). 3w arrays spread over and area will make more efficient use of the heat sink, which I will get to in a moment
4) Spectral control: with the 3w arrays, I was able to choose 6 different colors, and control them all individually. This is give me almost infinite, analog control over my color distribution
5.) Efficiency: I ran the numbers, and those particular multichips just cant touch cree yet. (our multichips at work are BETTER than cree, but again, too warm of color). Less efficiency means more energy goes to heat than light, and heat is the enemy of LEDs, and tanks w/o chillers.
So, what did I come up with? I have two fixtures, with 24 emitters each. The colors I chose were Cyan, Violet, Blue, Royal Blue, Cool White, and Neutral White. The ratio is 3:4:3:6:4:4. The panels are linkable, which means I can use either 1 or both connected in series with eachother, no alterations to the power supply or wiring will be required.
The heat sink is a flat, 1/8" aluminum plate, no fins. There are no fins because there are no fans, and without forced air convection, the increase in surface area of the heat sink due to the fins is largely negated by the stagnant air they trap. Air is an EXCELLENT thermal insulator. Fans are loud, require more power, and fail often. The whole unit is painted, which takes the emissivity of aluminum from 5% in its raw form, to 95%, which means this unit will rely heavily on radiation off the back surface for cooling.
For optics I chose 80 degree reflectors, eschewing the rapid led lens. Since I will have a splash shield, I'm already losing light once by traveling through an optic media. A reflector should catch just as much peripheral light and focus it down as a lens, but without the extra loss. Plus, the reflectors are much smaller than the rapid lenses, which allowed me to keep the overall height of the fixture to 2"
Well, sorry for the novel, its alot of words for just a few photos, but I will be sure to take more from here onward, especially once they are actually shining. I'm praying that I like the results. For years with halides, I have never been truly happy with their color.
https://lh4.googleusercontent.com/-MvlvGU6ZgXo/T9cusPi8MRI/AAAAAAAABM8/vOh4Lp_mxgE/s640/2012-06-11%252020.01.27.jpg
https://lh6.googleusercontent.com/-ZItCP7J-22s/T9cuuczdF-I/AAAAAAAABNE/COCQN_nusZI/s512/2012-06-11%252020.01.15.jpg
https://lh5.googleusercontent.com/-Kshp0Uz1fC8/T9cuxbnEDDI/AAAAAAAABNM/toBmbhmyTig/s512/2012-06-11%252020.01.02.jpg
https://lh4.googleusercontent.com/-_jwNkDNRXK4/UBFBMvFU8nI/AAAAAAAABOQ/sSc-grUe9Ek/s640/2012-07-23%252020.20.29.jpg
https://lh3.googleusercontent.com/-aTHC6D46E1o/UBFBZSwUo8I/AAAAAAAABOY/13t3yN7qeIo/s640/2012-07-23%252020.20.18.jpg
Sorry, not done yet, but I've read so many of these threads here lately that I wanted to throw my hat in. Now, I realized rather late in the game that I didn't bother documenting the build that much until now.
It has been a slow, over engineered garage build. The mechanical engineer in me came out, and though I work for an LED light manufacturer with a full machine shop, I wanted to challenge myself to make something without using my professional resources (mainly because it is hard to get machine time in between production), and I hate asking for favors. In the end, I want to remove my canopy all together, so I wanted something that would look attractive hanging as a pendant.
As for the LEDs, after MUCH consideration, I choose against the new trend of the multichips. The industry I work in uses multichips exclusively for high power lighting, and after my first few months here, I was very excited about the idea of using multichips, and was (and still am, to a point), convinced that they are the future of aquarium lighting. We use the most powerful and efficient multichips in the world, but they proved hard to come by, lacking optic choices, and arent currently available in correct spectra.
So, why did I choose against the "aquarium" multichips:
1) China......nuff said. I am skeptical as to their quality. The lack of useful detail on their spec sheet alone was enough to give me pause. I found the driving current data, thermal limits, and lack of spectral definition worrysome.
2) Lack of optic choices
3) Concentration of heat over small area. Wanting to get heat away from the tank, build something attractive, and build something WITHOUT FANS (that was a big driving factor in my build, my tank is kinda loud). 3w arrays spread over and area will make more efficient use of the heat sink, which I will get to in a moment
4) Spectral control: with the 3w arrays, I was able to choose 6 different colors, and control them all individually. This is give me almost infinite, analog control over my color distribution
5.) Efficiency: I ran the numbers, and those particular multichips just cant touch cree yet. (our multichips at work are BETTER than cree, but again, too warm of color). Less efficiency means more energy goes to heat than light, and heat is the enemy of LEDs, and tanks w/o chillers.
So, what did I come up with? I have two fixtures, with 24 emitters each. The colors I chose were Cyan, Violet, Blue, Royal Blue, Cool White, and Neutral White. The ratio is 3:4:3:6:4:4. The panels are linkable, which means I can use either 1 or both connected in series with eachother, no alterations to the power supply or wiring will be required.
The heat sink is a flat, 1/8" aluminum plate, no fins. There are no fins because there are no fans, and without forced air convection, the increase in surface area of the heat sink due to the fins is largely negated by the stagnant air they trap. Air is an EXCELLENT thermal insulator. Fans are loud, require more power, and fail often. The whole unit is painted, which takes the emissivity of aluminum from 5% in its raw form, to 95%, which means this unit will rely heavily on radiation off the back surface for cooling.
For optics I chose 80 degree reflectors, eschewing the rapid led lens. Since I will have a splash shield, I'm already losing light once by traveling through an optic media. A reflector should catch just as much peripheral light and focus it down as a lens, but without the extra loss. Plus, the reflectors are much smaller than the rapid lenses, which allowed me to keep the overall height of the fixture to 2"
Well, sorry for the novel, its alot of words for just a few photos, but I will be sure to take more from here onward, especially once they are actually shining. I'm praying that I like the results. For years with halides, I have never been truly happy with their color.
https://lh4.googleusercontent.com/-MvlvGU6ZgXo/T9cusPi8MRI/AAAAAAAABM8/vOh4Lp_mxgE/s640/2012-06-11%252020.01.27.jpg
https://lh6.googleusercontent.com/-ZItCP7J-22s/T9cuuczdF-I/AAAAAAAABNE/COCQN_nusZI/s512/2012-06-11%252020.01.15.jpg
https://lh5.googleusercontent.com/-Kshp0Uz1fC8/T9cuxbnEDDI/AAAAAAAABNM/toBmbhmyTig/s512/2012-06-11%252020.01.02.jpg
https://lh4.googleusercontent.com/-_jwNkDNRXK4/UBFBMvFU8nI/AAAAAAAABOQ/sSc-grUe9Ek/s640/2012-07-23%252020.20.29.jpg
https://lh3.googleusercontent.com/-aTHC6D46E1o/UBFBZSwUo8I/AAAAAAAABOY/13t3yN7qeIo/s640/2012-07-23%252020.20.18.jpg