DIY LEDs - The write-up

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I'm planning on getting my PC's up to supplement the LED array I built. I have a Coralife Aqualight Pro hood and I took it apart to try to incorporate the LEDs (and take out the MH light). However, I couldn't get it all to fit (no room for my power supply or LED driver module). So it's still in pieces because I ran out of time.

I also have a question regarding optics - I'd love to add them to my setup, however I think that the 25 degree is too narrow. Does anyone know if there is perhaps a 60-65 degree option? I want to keep the fixture relatively close to the water, but I also want to avoid the spotlighting effect. My calculations (rough though they are) seem to indicate that 60-65 degrees about 12" above the water's surface is ideal for me. But I can only find much narrower optics than that. (The spread of the LEDs as they are (no optics) is 90 degrees.

When I get my aqualight reassembled, I'll let you guys know how it looks (and maybe I'll even have my pics from the build uploaded by that time!). The main reason I want to run the PCs is because I'm using 50/50 bulbs, and need them to get actinic back (all the LEDs in my build are 'cool white' - which turned out a little warmer than i expected).
 
ReefE: When you don't mount the lens exactly as it's designed to be mounted, you are throwing away light, as the lens is no longer 'catching' all the light projected from the LED. You may think the projected spot is brighter and it may be, but you still lost a bunch of the light.

DheereCrossing; You are either badly over driving the LEDs or your wall wart is too small.

Yossarian99; I have a hard time imagining anyone needing more than 25~30degrees for an aquarium. You are talking about dinner plate spots at a foot or two. Look at the 25degree spot above.
 
<a href=showthread.php?s=&postid=14863080#post14863080 target=_blank>Originally posted</a> by kcress
ReefE: When you don't mount the lens exactly as it's designed to be mounted, you are throwing away light, as the lens is no longer 'catching' all the light projected from the LED. You may think the projected spot is brighter and it may be, but you still lost a bunch of the light.
Click to expand...

no argument there! Unless of course you're moving the lens closer than designed to make the beam a bit wider than 60.

I'm using 60 degrees... since I am basically using all my LEDs in one strip along the length of the tank at an angle. If I used the 20 degree optics it wouldn't hit my whole rockwork (top-to-bottom that is). But I agree in most cases the narrower ones are better. Soundwave's application is another example. With optics, even if they converged near the bottom, he'd have serious dim spots higher up in the tank between the LEDs. the design just has to account for it.
 
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Has anybody here messed with true actinic (referred to as "violet") LEDs??? The only ones I've been able to find are:

http://www.superbrightleds.com/specs/v1015_specs.htm

http://www.superbrightleds.com/cgi-bin/store/commerce.cgi?product=LEDS

They have emission at 420nm, but unfortunately they're just dinky 20mA, 5mm LEDs. I know the Royal Blue LEDs (~455nm) have decent actinic response, but it would be awesome to try some true actinic LEDs. These 5mms seem like a waste though, you'd need so many.
 
<a href=showthread.php?s=&postid=14862999#post14862999 target=_blank>Originally posted</a> by ReefEnabler
These are cheap 60 degree optics:

http://www.dealextreme.com/details.dx/sku.4628

you can control the spread by moving the lens closer or further from the LED.

My post a few pages back shows an example of this
Click to expand...

Now that you mention it, I remember your post now. So these are what you're using? How do they mount?

To answer the other question asked about why I want a spread as wide as 60 - it is mainly as you stated for SoundWave's desgin - I'm going to have many more interesting things higher up than just the bottom of the tank, and want even, strong lighting even 6-8" down from the top of the water surface. 20 degree optics will not accomplish that.

If those puppies you mention are easy enough to mount, and you say they work, I think I will go for it. I'm hoping to increase intensity while maintaining an 'even' look.
 
Yup thats what I got. I haven't figured out how to mount them yet... But I imagine it will be something hacky involving either aluminum tube or 3/4" PVC and epoxy :) Probably will not use the included black housing as I need them slightly closer, I dont believe they were designed for luxeonstars... probably more designed for 5mm LEDs that stick up off the surface a tad more. with the included housing, the distance makes the spot narrower than 60 degrees with stars IME.


I am finishing up my T5 retro (my final 660 ballast arrived today) and then I get to finish my LED work finally. All should be completed this week (It's hard to find time to commit to projects with an infant :) ) So I'll probably have a better actual example to show soon.
 
What the heck. It's pretty cheap, even for the number of LEDs I have. I'm going to order 'em and see what happens. If you find a clean, effective way of mounting them with the Cree LEDs, I'd love to hear it.
 
Facing, for me. I have them mounted on one end of each heatsink, blowing air parallel to the fins. The enclosure I'm using has ventilation slots in the top, where the warm air can escape.

I don't think you'll get nearly the same efficiency if the fan is pointing away, because the resulting airflow along the fins is nowhere near the same.
 
off topic question really, but i just made a post about this in a different section, and i figured it could really be applied here. does anyone think it would be beneficial to use fiber-optic cables/acrylic rods to move the actual source of the light beneath the waters surface in their aquarium? I was wondering if this would make more use of the light that is normally bounced off the water's surface, which appears to be a lot.
 
likewise, does anybody know how much light is lost off of the surface of the water? Does anybody know how much farther light from a high power Cree XLamp MC-E LED (400 lumens) would travel if it's source were underwater?
 
If I remember my high-school physics optics classes from so long ago, I believe you lose more light to reflection if the angle of incidence (the angle the light beam hits the water) is smaller. So, using optics (as we were discussing) would probably help with this also. I'm well beyond remembering the formulas for calculating this kind of thing, but if you have a narrower beam entering as close to 90 degrees to the water surface as possible, you'll get less loss due to reflection.

Of course, if the beam is too narrow you get the undesired 'spotlight' effect. So it's a balancing act.

Interesting thought to bring up. Until you mentioned it, I hadn't even considered how much we're losing to reflection.
 
I would assume it's a lot, or at least a consideral amount of loss in light. The surface of the watet always looks extremely bright from above.
 
1000mA of current flows through, since the buckpuck provides constant current. As long as the sum of teh forward voltages on all the LEDs don't exceed the input voltage on the buckpuck.
 
The life is supposed to be shorter but even if the light lasts 5 years, I'll just replace the LEDs. By that time, though, I'm sure something else will come along.
 
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