DIY LEDs - The write-up
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vthondaboi
Premium Member
C channel question
I picked up some 3/4" C channel from HD that's 1/16" thick. How many inches per LED would be safe?
I picked up some 3/4" C channel from HD that's 1/16" thick. How many inches per LED would be safe?
katchupoy
New member
Thank you for fast response Kcress. I building mine right now, and I was just wondering how you do yours... Thank you.
kcress
New member
vthondaboi; Usually it's not an asked question because other things dictate the spacing, like the width of the optics. Or the fact that you generally don't even want them spaced really close because you don't need that many LEDs to achieve the 15sqin/LED. You don't need them all directly next to each other. I'd say an inch or two, star edge to edge would be as close as you'd want.
kcress
New member
katchupoy;
The optics alllllmost stay on by themselves usually. So you need a really small amount of epoxy to hold them so they'd never just fall back off. After fitting a few, just look for a convenient spot where the optics touch the star.
Use a toothpick and dab a tiny amount onto the optic and then re-install it. I have also seen the other method where you put on the optic and then just dab a bit of epoxy somewhere at the seam between the optics and the star. Just enough to make a tiny little bridge across the seam. Often you want to use 30 minute or 1 hour epoxy because you have longer to apply it before it goes off on you. Then just leave everything and come back the next day.
The optics alllllmost stay on by themselves usually. So you need a really small amount of epoxy to hold them so they'd never just fall back off. After fitting a few, just look for a convenient spot where the optics touch the star.
Use a toothpick and dab a tiny amount onto the optic and then re-install it. I have also seen the other method where you put on the optic and then just dab a bit of epoxy somewhere at the seam between the optics and the star. Just enough to make a tiny little bridge across the seam. Often you want to use 30 minute or 1 hour epoxy because you have longer to apply it before it goes off on you. Then just leave everything and come back the next day.
wisewendell
New member
I am planning on building a fixture for my 48wx26tx24d 150 tank. Using 68 LEDs. 4 red, 4 green, 20 white and 40 blue. Using a 24V 10A driver with resistors and all that on a 16"X8" heatsink(square tube)that I will probably spread out a little to get around 10". Plan on using 24V PWMs to control the strength of each color. Will this be sufficient light to grow LPS and some SPS on? I plan on driving the bulbs not turning them down to 1/3rd power.
kcress
New member
I got ahold of an XM-L. I fed 700mA to it and was suitably impressed. Make that VERY impressed.
Besides the crazy amount of light - 260 lumens - that it spewed, I was impressed by the fact that I could hold it in my fingers without it getting noticeably warm. This means that if you ran XM-Ls at 700mA you could use a really minimal heatsink scheme.
I did screw it to a small stamped heatsink and cranked it up to 2A. That was 650 lumens or about 1/2 a 100W light bulb!! That started to warm up the heatsink a bit.
I'd probably consider 1.5A to be a good working maximum for the XM-Ls. That would still allow fairly lean heatsinking without a concern-able lifetime impact.
I can't see using them without optics though. The wide dispersion of so much light will have a lot of light hitting places it shouldn't.
I dropped some optics on it that included 25, 20, 15, and 5 degrees. They all made a great spot on the ceiling 5 feet above.
Any of those spots would make a great bike light with only the one XM-L. I didn't have any proper optics though. These were for LumiLEDs. They are the plastic cones with a recessed hole that fits down over the LED. They result in just about zero leakage out the sides. Anyway using proper optics and mounting them above the tank a foot or two would be great. You could crank the factors up to maybe 20sqin/LED.
Besides the crazy amount of light - 260 lumens - that it spewed, I was impressed by the fact that I could hold it in my fingers without it getting noticeably warm. This means that if you ran XM-Ls at 700mA you could use a really minimal heatsink scheme.
I did screw it to a small stamped heatsink and cranked it up to 2A. That was 650 lumens or about 1/2 a 100W light bulb!! That started to warm up the heatsink a bit.
I'd probably consider 1.5A to be a good working maximum for the XM-Ls. That would still allow fairly lean heatsinking without a concern-able lifetime impact.
I can't see using them without optics though. The wide dispersion of so much light will have a lot of light hitting places it shouldn't.
I dropped some optics on it that included 25, 20, 15, and 5 degrees. They all made a great spot on the ceiling 5 feet above.
Any of those spots would make a great bike light with only the one XM-L. I didn't have any proper optics though. These were for LumiLEDs. They are the plastic cones with a recessed hole that fits down over the LED. They result in just about zero leakage out the sides. Anyway using proper optics and mounting them above the tank a foot or two would be great. You could crank the factors up to maybe 20sqin/LED.
wisewendell
New member
Yes, LED's is what I meant
. What is the advantage of U-Channel over tubing? I figured since there was more surface area the tubing would be better?
ShallowWaters
Premium Member
Great thread - incredibly helpful! Unfortunately, I don't trust my handiwork when it comes to electicity and water. I am curious though - Now that you folks pioneered amazing work and researched parts all the way to end of the Internet, what commercial LED fixture company do you think makes the best lights by performance & value for SPS?
kcress
New member
Widdy; I don't have any Carlo's. I hope you're not saying the XP Carlos hold the optics out forward a lot. That is the total reason these otherwise perfect optics, I have, don't work. Their holder holds them out forward too far.
These XM-Ls are now going to allow one string to use all of the ELN60-48s output effectively.
However it means we can't mix blues in with them anymore. On small builds you could run one ELN for the XMs and maybe run two blue strings in parallel on the other. This would give 33%:67%. Problem is, it may now take 25%:75% XM-L:XP-E. (head scratching
)Yes, LED's is what I meant
What is the advantage of U-Channel over tubing? I figured since there was more surface area the tubing would be better?
U-channel is about 3 times better at dumping the heat than square tubing. The "back" side of the tube blocks all the other inside faces from radiating away their heat. That same face stymies all the convection possibilities too.
ShallowWaters; You're really asking in the wrong place. I don't think any of us even care. So we don't really know.
ArmanS
Active member
Aqua Illumination Sol modules are really popular and if you visit the thread on the lighting form it shows great par measurements. They are expensive but worth it if you wont diy.
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