Just noticed your post:
1. Why do you think LEDs are better than metal halide? My impression is that MH emit a huge amount of power as UV which is essentially useless (and actively dangerous), and that they don't dim well. However, otherwise they are more efficient than an LED and are cheaper. One that seems particularly odd to me is that I keep hearing that *20,000K* MH bulbs are too blue! At 20,000K, it should be putting out the majority of it's radiation at 140nm, way, way past the visible range and far into the range where it's extremely dangerous to look at or even shine on your body!
A couple points here:
1. You're totally correct about halides creating dangerous UV radiation. However, the glass shields this from actually exiting the bulb.
2. LEDs are far more efficient than halides at this point. While the best of the bunch halides may approach 100 lumens/watt efficacy in their first couple months of use, the common XP-G LED can do 120 lumens/watt no problem, and the new XM-L can do 160 lumens/watt.
2. How much can you get 10,000 lumen commercial LED fixtures for? I am absolutely confident that I can make an extremely nice one that I would happily sell for under $1500, likely less if I am making more than one or two. Thus, it's sort of a waste of my time to make my own if I can point my friends to one that is just as good and costs less!
I can't comment on commercial fixtures (they cost too much for me to give them the time of day :lol
, but for your 10,000 lumens:
14x Cree XM-L from cutter.com.au: $95
2x Meanwell ELN 60-24 to drive them at 2.5 amps: $70
Miscellaneous schwag: $30
Total cost $200 for 10,000-11,000 lumens
This is all white light though, if you're looking to make an aquarium fixture it would cost maybe a little more, but then you don't want to describe it in terms of lumens, as lumen count is a very poor way of referring to intensity of the deep blue light.
3. What are good sizes for me to design for? I could make a 2' long, 5-6" wide fixture that puts out 10,000 lumens, or a 4' long that puts out 20,000 lumens, and so on. But I'd like to design them to be as close as possible to what a general aquarium user might actually want.
This is starting to feel very commercial :lol:; you're going to want to stay underground with your commercial notions or you'll be censored here.