paenian June 16, 2008 June 16, 2008 I recently purchased 18 cool-white Batwing luxeons, which I've determined to be the best in terms of lumens/watt output without breaking the bank - specifically 45 lumens per watt. (If you want to break the bank, look at the Luxeon Rebel LEDs) I got 18 because that's the most that a standard Buckpuck can drive, making this a fairly optimal setup cost-wise as well. This was a test run; for an actual light, I will add two more strings: one white and one blue, total of 54watts and about 2000 lumens output, all of which should be photosynthetically active. So do forgive the rough nature of this setup. The circuit - I don't think you need a schematic... it's three sets of six LEDs in series, connected to the buckpuck drive current. Puckpuck gets power from an ancienct computer power supply; 24V in, regulated 1.05 amps out.
paenian June 16, 2008 Author June 16, 2008 So that circuit works like a charm, but the Batwings' viewing angle is 110 degrees - a bit wide, so I built a reflector out of some aluminum flashing. Planning the reflector - did a little ray tracing to see what angle would work well. the reflector itself I should post about the power supply... gutted from an ancient computer, barely has enough power on the -12 rail (to get 24 volts from a computer, use the + and - 12v rails). Won't work on more LEDs, sadly; it's already overdriving the transistor. the workbench, pre reflector:
Larry Grenier June 16, 2008 June 16, 2008 This is very cool stuff (pun intended). Keep us posted & thanks for sharing.
paenian June 16, 2008 Author June 16, 2008 Pics of the unit in action, along with a commercial model. The commercial LEDs are 3 watt, I have a feeling they're just the next step up in the Luxeon line. Also note that each of them has its own reflector. Current status: ordering more LEDs, to fill up the reflector. I also need a heat sink; currently my LEDs dim after a few minutes because the rear gets too warm. I am hoping to set up the full 54 watt unit in a couple of weeks, at which point I'd like to borrow a PAR meter. I was wondering if anyone has old lights that I could borrow and compare to? I'm thinking about setting this up in its own small tank, then trying it out with a selection of inexpensive but increasingly light-loving corals - donations welcome, I'll post when I'm ready. Questions in the meantime?
fishcam June 16, 2008 June 16, 2008 Pics of the unit in action, along with a commercial model. The commercial LEDs are 3 watt, I have a feeling they're just the next step up in the Luxeon line. Also note that each of them has its own reflector. Current status: ordering more LEDs, to fill up the reflector. I also need a heat sink; currently my LEDs dim after a few minutes because the rear gets too warm. I am hoping to set up the full 54 watt unit in a couple of weeks, at which point I'd like to borrow a PAR meter. I was wondering if anyone has old lights that I could borrow and compare to? I'm thinking about setting this up in its own small tank, then trying it out with a selection of inexpensive but increasingly light-loving corals - donations welcome, I'll post when I'm ready. Questions in the meantime? I've got a few massive heat sinks used for the old athlon processors you could use if you're interested... one has a solid copper base, with aluminum pegs for fins, and the other is just solid copper with giant copper fans (swiftech and zalman if you know the brands). Anyway, they're not worth much nowadays... so make me an offer if you're interested... I'm trying to raise enough "free" capital for a pico
Integral9 June 17, 2008 June 17, 2008 Looks good. Pics remind me of my ECE days back in college. I miss my breadboard sometimes. btw. What are you using to mount the LEDs to the heatsinks? I used to be into over clocking and I've got a ton of old computer parts lying around my basement. I think I even have a 430W ATX PS you can have if you are interested. I know I have a 300W ATX PS or two lying around. I also got fans and heatsinks (Slot 1 and newer), and maybe and old 30W peltier if I can find it. Let me know if you are interested in any of it.
paenian June 18, 2008 Author June 18, 2008 Looks good. Pics remind me of my ECE days back in college. I miss my breadboard sometimes. btw. What are you using to mount the LEDs to the heatsinks? I used to be into over clocking and I've got a ton of old computer parts lying around my basement. I think I even have a 430W ATX PS you can have if you are interested. I know I have a 300W ATX PS or two lying around. I also got fans and heatsinks (Slot 1 and newer), and maybe and old 30W peltier if I can find it. Let me know if you are interested in any of it. Right now the LEDs are just taped to the reflector; the reason I got the buckpuck is so I wouldn't have to worry about that - it'll lower the power as heat increases, dimming the leds so they don't overheat. I'm thinking about switching to the plain emitters (without the hexagonal plate) and just using thermal tape to mount, or using thermal epoxy. As for power supplies, this circuit takes 24 volts, at .75 amps; to get this out of a computer supply I use the +12 & the -12. I checked all my computer supplies, none puts out more than one amp on the -12, so most won't really scale to even 54 LEDs. I think a 12-24v transformer would just add inefficiency, so I'm looking for a straight 120-24V transformer. That buckpuck does power conditioning and everything, so dirty line power should work fine.
jason the filter freak June 19, 2008 June 19, 2008 Neat project, I've seen sooo many of these led projects fail, including my own. Whats the candle for?
Kengar June 19, 2008 June 19, 2008 Neat project, I've seen sooo many of these led projects fail, including my own. Whats the candle for? backup lighting when the LED's fail.
paenian June 20, 2008 Author June 20, 2008 Neat project, I've seen sooo many of these led projects fail, including my own. Whats the candle for? It's just a weight... or as a reference one-candela source. My LED supplier is out of the bits I want... so delay pending more gear, or I'll just break down and buy elsewhere. So far I'm not in any hurry on the project.
Integral9 June 20, 2008 June 20, 2008 Right now the LEDs are just taped to the reflector; the reason I got the buckpuck is so I wouldn't have to worry about that - it'll lower the power as heat increases, dimming the leds so they don't overheat. I'm thinking about switching to the plain emitters (without the hexagonal plate) and just using thermal tape to mount, or using thermal epoxy. The tape will probably hold better than the putty once it gets hot and the LED melts into it. But it will get soft again once it heats up. The putty will hold eventually but it'll have to get old and dry out before it gets really sticky. Before that happens I wouldn't be surprised if Mr. Gravity just pulled the LEDs down. And even if it doesn't you'll probably get an air gap. Air in the tape or putty will basically ruin your heatsinks ability to draw heat away, so I think you are going to need a clamp or some way to secure the LEDS. Some clear scotch tape should do fine,just cut a hole for the LED to poke through. As for power supplies, this circuit takes 24 volts, at .75 amps; to get this out of a computer supply I use the +12 & the -12. I checked all my computer supplies, none puts out more than one amp on the -12, so most won't really scale to even 54 LEDs. I think a 12-24v transformer would just add inefficiency, so I'm looking for a straight 120-24V transformer. That buckpuck does power conditioning and everything, so dirty line power should work fine. Newer ATX PS have two 12V rails and from what I can tell, they can put out 16.0A or more per rail. That should be enough for you. The computer PS will also condition the power a bit. No battery back up, but there are caps to counteract quick browns and surges just make it laugh until the fuse pops. http://www.antec.com/us/productDetails.php?ProdID=27430
paenian June 23, 2008 Author June 23, 2008 Just bought a bunch of stuff. Thermal tape for the heat interface, with some acrylic in front to keep salt/corrosion at bay. Does anyone have some small bits of optical acrylic I could buy? Local plastics supplier? I want some of the good stuff... 1/8-1/4" thick. I'm missing that and a permanent heat sink, looking for something that looks nice since I don't like hiding electronics in cabinets. Is there a surplus store around?
Integral9 June 26, 2008 June 26, 2008 Home depot has acrylic, but I don't know if it's "optical" but it's clear. I have a piece 1/8" hanging over my 30g. Work's great except it bows after a day or so, so I flip it over every day to keep from falling in the water. Better to get the 1/4" imo.
paenian July 20, 2008 Author July 20, 2008 Two units installed! Each unit is 36 white & 18 blue LEDs. It's brighter than my power compacts, and I'm in line for the PAR meter, ETA about a week. I'll post some pictures when I'm less tired.
jason the filter freak July 20, 2008 July 20, 2008 Can't wait to see the pics, also can't wait to see the par ratings, for say a year from now.
paenian July 23, 2008 Author July 23, 2008 Pictures! I was going to just post pictures of the new LEDs in action since folk seemed interested, but then realized I should probably introduce the tank, since it's somewhat non-standard. To start with, our tank is a homemade 50 gallon octagon with a central, square overflow aligned with one of the inscribed squares. So it's not parallel to any of the tank's sides. Each glass panel is a foot wide, tank is 16" deep, overflow is 8" square. Current is circular, designed for river fish (Columbian Cat Sharks) that grew up and left home for greener pastures :( . 30 gallon sump underneath. Full tank shot, rather old, but we haven't taken one recently:
paenian July 23, 2008 Author July 23, 2008 For lights, we had four 32W PC bulbs arranged around the overflow box, and have now added two LED fixtures. They're 14" by 4", aluminum flashing reflector with 54 1 watt Luxeon I batwing emitters. Three sets of eighteen, with six blue and twelve white each. Cooling is provided by attaching them to an aluminum sqaure tube and running a fan through there. They're attached to the outside of our light pendant, inline with the front two PC bulbs. They've been running for less than a week, and already growth is obvious. Of course, the PC's were hopelessly underpowered; I'll post PAR readings of both as soon as I can. For now, comparison pictures; recall that with the PCs you have four lamps, while for the LEDs there are only two in the front - the back is dark. PCs: LEDs: PCs: LEDs: PCs: LEDs: LEDs reflecting off the surface of the water - it's a little too bright to look at, and the dancing lines on the wall are pretty awesome: That's all for now. More when PARs are available.
Larry Grenier July 23, 2008 July 23, 2008 If you don't mind my asking... where did you get the commercially made section you're using as a comparison? How much was it? Could several of those be used? For us electronically challenged folks.
paenian July 23, 2008 Author July 23, 2008 The commercial one came from Marine Depot here, $60, can use up to three on the same power supply. Not bad little devices, but the light is very focused; I'm sure enough would give a similar effect, but you'd need a lot. I'm not planning on using mine anymore, actually, and would be willing to trade for something purty if you'd like to check it out. These guys aren't that difficult to build, and I'm thinking of ways to make them even easier. I figure if they work out I can sell some at cost to some beta testers, buy in bulk to save $$. Right now I'm too poor to play with 'em much more. Paul
paenian July 24, 2008 Author July 24, 2008 Pictures of the installed units, & full tank shot. After three days with the LEDs, everything looks much happier - the mushrooms are huge and the pulsating xenia pulses a lot more. Also have free frags of the kenya trees if anyone wants 'em - it's spitting out two or three a week now, so far just throwing them away.
jamesbuf July 24, 2008 July 24, 2008 thats pretty awesome... Agreed. Definitely really cool. I'd be interested in trying a lamp out over a frag tank. If you ever do that bulk buy and need beta testers, count me in.
jamesbuf July 24, 2008 July 24, 2008 Gee, I wonder if you could be Paul Chase who gave the review here: http://www.marinedepot.com/ps_viewItem~idP...1645~tab~4.html
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now