NanoReefGuy Posted October 4, 2008 Author Share Posted October 4, 2008 Hi Evil & Reeferton I am fairly sure that I should do the polishing. As Evil points out it will increase the direct contact between the LED star, the aluminium plate and the sink. I am also liking the idea of being able to bounce some of the reflected light from the water back down. Also I think that a polished surface is less likely to corrode. At work we have done test on different heat sink compounds. In this application we are running 50-60W diodes that need to have very stable temperatures. Arctic Silver got the nod. As far as the 10K LEDs there are some bins that have LEDs that are this high in CT. So far I haven't seen them available in small quantity very often. Is it possible that they mean a combination of blue & white that has a total CT of 10K? Cheers NRG Link to comment
Reeferton Posted October 4, 2008 Share Posted October 4, 2008 If the aluminum is mat, start with 400, then 600 sandpaper. Use the good stuff, not the wood sand paper. If there are scratches start with 300 and go from there. To do it right, get Graystar and Zam compounds and muslin buffs for a dremel or whatever. Graystar removes the fine scratches, zam will give it a luster. Use 50/50 ammonia/water to clean the graystar prior to polishing with zam or it won't polish properly. If you don't use polishing compound with the buff, all you are doing is removing surface oxides and not actually polishing. You can get all this stuff from contenti.com Hope this helps. Link to comment
Gomer Posted October 5, 2008 Share Posted October 5, 2008 Hi Evil: Well I am retro-fitting it into a spare BC29 canopy, so the array will be about 1.5" off the water. It will be enclosed in the clear plastic shield that is in the stock canopy to help keep moisture from being a problem and to force the air flow through the heat sink. Just working on layout of the aluminium so that I can drill a bunch of holes & then go crazy with the taps. I seem to recall that you did this instead of using thermal epoxy. Do you happen to recall what thread size fits well? It looks to be around 6-32 or 4-40. Cheers NRG I think I was able to use 6-32 when I did it Link to comment
snatchbak Posted October 5, 2008 Share Posted October 5, 2008 You aren't missing anything. There is no dissadvantage electrically to what you are doing, providing your drivers are able to handle the max voltage of the entire string. I don't see any advantage of running a Xitanium driver over a Buckpuck. Lower voltage DC in moist/wet conditions is generally considered safer than running 120VAC. Plus, by the time you get into the higher wattage version with dimming control, you are spending a ton of money ($85 for a 24W dimmable, which has lower output voltage than the Buckpucks) just to elliminate a power supply. Doesn't seem worth it to me. If you weren't mixing and matching so much, you could use 1 LED driver with multiple strings, running parallel. I have a BC 29 and my tank has switches that carry 120VAC in the hood... What do you have?? 25W dimmable version is only $55-ish at Future Electronics. I went with the 40W xitanium non-dim and its cheaper than the 25W dimmable. And as far as voltage, 24v output allows for 6 stars per string. I like having less parts so... having a power supply and driver in one box...or not. And if you dont want 120v in the hood, than you could put the driver in the stand........ Link to comment
NanoReefGuy Posted October 5, 2008 Author Share Posted October 5, 2008 Hi Snatchbak I don't think mixing and matching will be a problem. All the LEDs that I am using are rated to at least 700mA, which is the max that I will be driving a string at. I don't think the 25W version would be a great help because the total LED power that I am planning is over 100W. I would still reqiure 4 of these current drivers. 48LED x 3.5V (Vfwd) x .7A = 117.6W. So I would actually need 5 of them @ $55 this would be $275. I have a 24-48V 600W DC power supply already so I needed 8 buckpucks @$18 = $144. My stock hood has 120V to the switches, but in the retrofit I took all that out. I only have a DC voltage (24 or 32V haven't quite decided for sure yet) coming up to the hood. I have the power supply down in the stand (this helps keep heat out of the aquarium) I don't disagree with your solution. Just that given I already had some of the parts it made sense for me to do it this way. If I were to start again I would follow DarkDevil's recommendation skip the Buckpucks & make my own drivers using National Semi's LM3404. It would take the cost per unit down to around $8. Usually I am very interested in minimal parts, but there are a couple advantages I see to having more stings of LEDs: -I should be able to get more control over the total amount & mix of light. -In the event of an LED failure I will only lose a portion of the light. When LEDs fail they tend to go open circuit. Current drivers don't like being connected to an open circuit. If this were to cause a driver failure I would only lose a portion of the light until the driver and LED could be replaced. Good to see different solutions Cheers NRG Link to comment
snatchbak Posted October 6, 2008 Share Posted October 6, 2008 cheers. I just finished my LED upgrade today. Everything worked accept the 2 UV moonlights, which are wired incorrectly. I'm running my K2s at 875mA. I'm super happy with how everything turned out. The colors are very even and my tank looks crisp. The LEDs make a nice shimmering effect. I'm glad I used 8 blue and 4 white instead of a 50/50 mix. I wanted more of a blue spectrum. I'll post some pics soon. How much are those buckpucks anyway? Link to comment
NanoReefGuy Posted October 6, 2008 Author Share Posted October 6, 2008 Hi Snatchbak WE WANT PICS !! Congratulations on getting your LEDs shining! I bought buckpucks for $18 each from www.luxeonstar.com Which UV LEDs did you use? I bought the ones from Kaidomain and am not sure if the aluminium star is electrically isolated from the rest of the LED. It may have a short path through the heatsink. Are the UV LEDs you are using isolated from the aluminium? Talk to you soon NRG Link to comment
NanoReefGuy Posted October 8, 2008 Author Share Posted October 8, 2008 Hi All Just a quick update to show how the heat sink turned out: I used m5 screws to hold the heat sink tighter on the aluminium plate. In addition the m3 screws that hold the LED stars in place will help to keep the pressure between the pieces up! Still have plastic on the face of the aluminium. I will remove this when I am ready to put on the LED star. I still need to drill holes beside each star mounting location to run the wires. Then I need to polish the bottom of the heatsinks and the top of the aluminium to get max heat transfer. Then I have to assemble with Arctic Silver. Man I am tired of drilling holes and tapping them... Cheers NRG PS Snatchbak any pics yet? Link to comment
DarkDevil Posted October 8, 2008 Share Posted October 8, 2008 feel my pain... but looking good! Link to comment
evilc66 Posted October 8, 2008 Share Posted October 8, 2008 Nice NRG. All the labor will be worth it. I'm tempted to order my heatsink today (8.5"x36" @ 16.5lbs ) for my next project because all of the LED projects going on right now. I gots da itch! Link to comment
NanoReefGuy Posted October 8, 2008 Author Share Posted October 8, 2008 Well you know what they say... If you got an itch then scratch it! What "evil" plans are you making now? Cheers NRG Link to comment
Zombo Posted October 8, 2008 Share Posted October 8, 2008 Well you know what they say... If you got an itch then scratch it! What "evil" plans are you making now? Cheers NRG Of course, part of his plans include turning out another evilCink™ for my soon-to-arrive-and-be-gutted CADlights 22g lighting Of course, I have no chance in hell of matching the sheer elegance of your DIY masterpiece, DarkDevil. Link to comment
evilc66 Posted October 9, 2008 Share Posted October 9, 2008 Well, I hinted to it in the last post. It will be a 3ft long fixture that will be entirely heasink. The array will be very high power. 35 stars total with 31 being triple Rebel stars with white and royal blue (1:1 mix), and 4 3W UV. Rebels will run 25 degree optics, UV's will be bare. This will be the one where I dive into setting up a controller and LCD to manage things. Should be fun. Zombo, don't kid yourself. The retro you did turned out awesome. Very clean. I'm sure the CADlights will turn out just as good. PM me with what you want for the heatsinks. Link to comment
DarkDevil Posted October 9, 2008 Share Posted October 9, 2008 Zombo, I am flattered, your light is very clean just as evilc66 said, it looks awesome. my light looks good just because I got a crappy camera and crappy photo skillz, most of the blemishes and boo boos got mushed up, just like the 300 lb girls look just as hot in pictures Link to comment
NanoReefGuy Posted October 9, 2008 Author Share Posted October 9, 2008 Holy %#(* evil! 97 emitters even at a cool 2.5 watts per this will be >240W of blinding LEDness! Clearly you are taking your positon as GAWD seriously! Are you using the 180lm CW Rebels? I saw someone on ebay with a decent deal for Rebels http://cgi.ebay.com/HIGH-POWER-LED-WHITE-L...id=p3286.c0.m14 It worked out to $3 each although these are "only" the 130 lm ones. Or have you found a sweet deal on a bunch of LEDs??? Cheers NRG Link to comment
evilc66 Posted October 9, 2008 Share Posted October 9, 2008 Yeah, it's pretty stupid. Maybe a little too much? Chances are I'll only need to run the damn thing at 50% power. I might reduce the number of LEDs a little, but with the CAD model of the light study using 25 degree reflectors, I get about 70% overlap on all sides which I like. I could space things out a little and take out maybe 25% of the emmiters, but isn't anything worth doing worth overdoing? Thats not a bad deal on the Rebels. I'm trying to get the 180lm bins from Future. They have them for a decent price, but I have heard they are hesitant on breaking up reels right now. We'll see. Link to comment
steve0xr Posted October 9, 2008 Share Posted October 9, 2008 This may be a dumb question but why not mount the leds directly to the heatsink? Link to comment
NanoReefGuy Posted October 9, 2008 Author Share Posted October 9, 2008 Hi evil Well they say excess is best and I think you're going for it in spades! If you turn the thing on and the water below starts to boil then you've gone too far... Hi steve0xr I think Evil is planning to mount directly on the sink (evil?) In my case I had a bunch of smaller sinks and wanted to be able to handle them as a single unit so I am mounting them all on a common plate. In my case the emitters are evenly spaced, but at night I will only be running a few for moonlight. There will be enough conduction/convection to keep the moonlights cool without needing a fan so it will be quieter. Cheers NRG Link to comment
evilc66 Posted October 9, 2008 Share Posted October 9, 2008 Right. I'm getting one large heatsink that will cover the entire area that needs to be lit (length wise anyway). I will be able to bolt the stars directly to it. Sometimes a single heatsink is not always easily available to meet the needs of the project, like NRG's and DarkDevils. The way they did it will lose a little thermal efficiency, but not enough to make it a problem. Link to comment
snatchbak Posted October 13, 2008 Share Posted October 13, 2008 http://i121.photobucket.com/albums/o207/sn.../1sttime2-1.jpg http://i121.photobucket.com/albums/o207/sn...bak/1stTime.jpg These 2 pics above are the first time around. http://i121.photobucket.com/albums/o207/sn...bak/2ndtime.jpg I thought I'd try the lighting like this too. It would have been nice if there was another PC lamp in the back, making 3 total. I didn't want to spend more money. Maybe one day... http://i121.photobucket.com/albums/o207/snatchbak/Final2.jpg http://i121.photobucket.com/albums/o207/snatchbak/Final1.jpg The 2 pics above are the final product. http://i121.photobucket.com/albums/o207/snatchbak/LED.jpg The LED fixture output. Link to comment
evilc66 Posted October 13, 2008 Share Posted October 13, 2008 Why didn't you go strictly LED and add a few more whites? You certainly had enough LEDs to do it. Link to comment
snatchbak Posted October 13, 2008 Share Posted October 13, 2008 why wouldnt I want to utilize the PC lighting I already have? I've had great success with the 2-36W PC. Now I have the light output I had before, plus more. I will upgrade the LEDs later by adding some sort of reflector... (no lense) The only thing I wish I would have done is polish the sink, whatever. Here is a pic of the wiring... Link to comment
evilc66 Posted October 13, 2008 Share Posted October 13, 2008 Reason I say that is going with LEDs removes a lot of heat from the water. Continuing to use the PC bulbs kind of negates that. I'm not saying that what you have done is a bad thing, just that you could fairly easily support your tank just off the LEDs and reduce your heat and consumed energy. Link to comment
snatchbak Posted October 13, 2008 Share Posted October 13, 2008 True. I actually added another fan, I only had one before. The LEDs have not affected the temp. of my tank at all. In fact, it actually runs cooler because of the dual fans and more vents added to the top of the hood. Link to comment
NanoReefGuy Posted October 16, 2008 Author Share Posted October 16, 2008 Thought I would do an update on the LED project... I have polished the aluminium plate, the heat sinks, and the back of the LED stars. Here is an example of the finish with 600 grit sandpaper. It feels smooth to touch. Here is an example of the finish after polishing. This + Arctic Silver should optimize heat transfer. The first 12 LED emitters are installed. Only 36 more to go First teaser shot of the controller The blue & white numbers are the brightness level on a scale of 0-255. When the lights go on/off the controller will ramp up or down at 1 unit every 10 seconds. Cheers NRG Link to comment
Recommended Posts
Archived
This topic is now archived and is closed to further replies.