coolwaters Posted June 15, 2007 Author Share Posted June 15, 2007 its better to use less then the maximum capacity of the driver or ballast. i calculated my small AC adaptor only gives out about 20w without melting... so i might have to get another $14 AC adaptor... i want to get thos 60w LED drivers...and power it over my 10g XD im planning to order about $60 of LEDs and lense by the end of this week. (or end of this weekend. Link to comment
coolwaters Posted June 16, 2007 Author Share Posted June 16, 2007 just wanted to say how out raged i was when i saw a flashlight at wal-mart for $25 and it only had one K2 luxeon LED in it. the worst part was it didnt come with batteries... Link to comment
coolwaters Posted June 16, 2007 Author Share Posted June 16, 2007 alright i can get a 60-75 watt LED driver for $30 to the door. which is pretty good. and i can get the 75w at 24v so i can wire 2 sets of 6 LEDs in my 10g at 48 watts. which is pretty dam bright.... or i can get the 60 watts driver thats 12v which is is the same just in series of 3. i'll probably go with the 24v since its stronger. Advance Xitanium 60W 12V LED Electronic Driver or Osram 75W Electronic LED Driver Link to comment
HecticDialectics Posted June 16, 2007 Share Posted June 16, 2007 I still really think you're dramatically underestimating the amount of leds you need if you want a moderate to high light setup. Link to comment
coolwaters Posted June 18, 2007 Author Share Posted June 18, 2007 i bet u dont have one. or havent really seen one in action. they seem weak thats because it is so dense. you would need reflectors or even better, Lenses (Fraen Lenses: they specialize in lense for luxeon LEDs.) i dont have lense but that doesnt really matter since im using it for a pico type tank. like if i use small angle lenses and shine about 4 LEDs in one spot thats pretty strong. its not fair to compare a 5 watt LED light to a 250 watt metal halide bulb and its not fair to the metal halide if u compare it with a 250w LED array. Link to comment
HecticDialectics Posted June 18, 2007 Share Posted June 18, 2007 i bet u dont have one. or havent really seen one in action.they seem weak thats because it is so dense. you would need reflectors or even better, Lenses (Fraen Lenses: they specialize in lense for luxeon LEDs.) i dont have lense but that doesnt really matter since im using it for a pico type tank. like if i use small angle lenses and shine about 4 LEDs in one spot thats pretty strong. its not fair to compare a 5 watt LED light to a 250 watt metal halide bulb and its not fair to the metal halide if u compare it with a 250w LED array. The LEDs look bright because they're a point source of light. You can stare at a single 1W led and think "holy crap I'm gonna go blind!" I don't know what kind of light intensity you're getting, but our eyes are horrible at determining the real light intensity. Maybe a lesser amount of leds are needed on smaller tanks though. If you decide to go with a small number of leds anyway, I would suggest you get the lenses even more. Any light that hits the surface of the water at more than 45 degrees is reflected off and doesn't penetrate. The lenses help focus more of the light to a usable angle. Link to comment
coolwaters Posted June 19, 2007 Author Share Posted June 19, 2007 im guessing 23 degree angle lights are the way to go. im starting my 15g project later so it should be a good tank to test it on. lol my 3g is pretty much rejected... Link to comment
somoney Posted June 20, 2007 Share Posted June 20, 2007 well my heat sink was about $0.75 each (found that one heat sink per LED is great.) well let me sum it up. $.75 heatsink $4.00 per LED $15 for transformer at walmart $10 silver 5 heat sink compound (recommended) $1/free wires. 22g is good enough $1/free for duct tape so about $60 shipped to your door IME. im rethinking about using 6 LEDs on this array cuz the transformer was burning up at 20 mins... i might have to get another transformer to split up the work.... WOW! Thats pretty sharp looking. Im too lazy though so Im ording an 8LED Blue/White Bar off ebay $20 shipped w/transformer" I ordered a 4LED Moonlight from this guy a year ago and there still running strong. Im going to supplement my existing T5 array with this Wide Angle 8 LED Blue/White bar and put a clam directly under it. Link to comment
prisonspider Posted June 20, 2007 Share Posted June 20, 2007 I just bought from that same dude a 15 LED for my NC fuge & Chaeto http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...em=110140797828 Do you think a 15 LED is too much as a fuge light? I saw he has 8's as well? Link to comment
somoney Posted June 20, 2007 Share Posted June 20, 2007 I just bought from that same dude a 15 LED for my NC fuge & Chaeto http://cgi.ebay.com/ws/eBayISAPI.dll?ViewI...em=110140797828 Do you think a 15 LED is too much as a fuge light? I saw he has 8's as well? MOre than enough for Chaeto. The guy is pretty cool, I've asked him to start selling more Blue/White LED arrays. He says he's working on them. Link to comment
HecticDialectics Posted June 21, 2007 Share Posted June 21, 2007 I'd hate to rain on you two's parade... but those are wide angle leds. 120 degrees means that you're only getting a bit less than 40% of the total light actually entering the tank. Light hitting the water at a greater than 45 degree angle bounces off (basic physics). Those are also not high powered leds. The total power consumption is only 1.2W. That will -not- be able to sustain a clam. I'd be surprised if it could even keep cheato alive. Link to comment
strangelove Posted June 21, 2007 Share Posted June 21, 2007 I'd hate to rain on you two's parade... but those are wide angle leds. 120 degrees means that you're only getting a bit less than 40% of the total light actually entering the tank. Light hitting the water at a greater than 45 degree angle bounces off (basic physics). Those are also not high powered leds. The total power consumption is only 1.2W. That will -not- be able to sustain a clam. I'd be surprised if it could even keep cheato alive. Do you mind if I ask, what is your expertise on this subject? I think Coolwaters DIY project is... cool. Keep up the good work and don't let nay sayers bumb you out. From what I've seen of LED projects people are getting things done right. A little experimenting never hurt, and it's fun too. So more power to you. Link to comment
coolwaters Posted June 21, 2007 Author Share Posted June 21, 2007 chaetos dont really need much. if u want them to grow like crazy get some high powered 470nm higher is better. in a few hours you'll see it extend to the light. people have made some small LEDs for grow chaeto it wont be fast thats for sure. if i were u guys i would get some submersible LED tubes almost 100% of the light goes in your tank. dam i should have gotten that LED driver when i had the chance... Link to comment
coolwaters Posted June 21, 2007 Author Share Posted June 21, 2007 does anyone have any ideas on how to design a water tight tube that can hold LEDs along with a heat sink? having a submersible hood is a pretty cool idea. Link to comment
HecticDialectics Posted June 21, 2007 Share Posted June 21, 2007 Do you mind if I ask, what is your expertise on this subject? I think Coolwaters DIY project is... cool. Keep up the good work and don't let nay sayers bumb you out. From what I've seen of LED projects people are getting things done right. A little experimenting never hurt, and it's fun too. So more power to you. lmao. I know don't know basic physics, but I'm good at research... Do you have -any- idea what the PAR or lumens a 1.2W led array puts out? Do you have any idea what PAR or lumens the K2s put out? Do you have any clue what PAR corals receive in the wild? If something doesn't come close to working on paper using spec sheets and basic physics, it's definitely -not- going to work in real life. This isn't some vast unknown experimental subject. Data is widely available. I don't comment on iffy ground. But, when I can blatantly tell that something might be wrong or ineffective from all of the research I've done, I'm going to let people know. A 1.2W led array is going to have much less light intensity than a 12W PC. Those aren't efficient high powered leds. The array Coolwater made is definitely miles ahead of that 1.2W led array. He's definitely on the right track, but again, using spec sheets and available test data on the lumens those K2 leds put out, you can very evidently see that the light intensity will not be very high. edit: physics claim editted due to recent physics-ownage haha Link to comment
coolwaters Posted June 21, 2007 Author Share Posted June 21, 2007 doesnt the sun give off around 33,000 PAR? something like that... and Metal halides have like 12,000? its been a while since i saw the stats. HecticDialectics is right the output of the K2 from Luxeon isnt very good. but its the cheapest and easiest LEDs i can find online...so the best thing i can do is just add more LEDs and add in a lense to focuse a lot of light close together. i found a company that makes almost the exact thing its called Edixeon <-- lol but its not a big company and its only in Taipei, Taiwan but the the stats on thos are almost 2 times better then luxeon. makes me wonder... help me look for some strong leds please XD Link to comment
coolwaters Posted June 21, 2007 Author Share Posted June 21, 2007 it just occurred to me that im losing about 72% of my light output...because of the wide angle... so out of my 31.2 watts in my array only 8.7watts are being used...or something like that. i really need thos 25 degree lenses...i'll order then on monday and i'll do a picture update when im finished. which is probably by thursday. Link to comment
coolwaters Posted June 21, 2007 Author Share Posted June 21, 2007 i found this very informating site http://www.biology-online.org/biology-forum/about11170.html compares red light to blue. (i want a 500nm light!!!) it probably doesnt help out coral mainly because it doesnt have chlorophyll A or B.... but it goes help out our chaeto or other micro aglae. and this http://realcolorwheel.com/realcolorwheel.htm to find out which color absorbs to which. *u can have 1000w of green light shining at a green plant and it probably wont grow as fast as if u where to shine a 100w red or blue light on it.* and i thought the bio system in a reef tank was complicated.... Link to comment
prisonspider Posted June 21, 2007 Share Posted June 21, 2007 I was just looking for a small fuge light for chaeto so I should be fine. As far as clams, etc. I see your points above and will stick with my MH Good thread though ... thanks Link to comment
neanderthalman Posted June 22, 2007 Share Posted June 22, 2007 If you decide to go with a small number of leds anyway, I would suggest you get the lenses even more. Any light that hits the surface of the water at more than 45 degrees is reflected off and doesn't penetrate. The lenses help focus more of the light to a usable angle. lmao. I know basic physics, and I'm good at research... You might want to double check your "basic physics". At an angle of incidence of 45 degrees, about 2.4% of the light is reflected off the surface of the water. Caution, basic physics below Air and water are both dielectric, so we can use the Fresnel equations for dielectric media. Many thanks to wikipedia for providing neat little images of the equations so I don't have to make my own. Now, we can't use these equations without first knowing the transmission angle, which can be easily calculated using Snell's Law. This requires knowing that the index of refraction of (sea)water is about 1.3. So, n1 (air) is approximately 1, n2 (water) is approximately 1.3, and the angle of incidence is 45 degrees. Using Snell's Law, given above, we find that the transmission angle is about 33 degrees. Now we can use the Fresnel equations to determine the reflection coefficient. Using the same values of n1, and n2, as well as the same angle of incidence and transmission angle, we can calculate that Rs is about 0.0455 and Rp is about 0.00208. For those with no physics training, Rs and Rp are for different polarization directions of the light. Since the light in this question is unpolarized, then the reflection coefficient is given as the average of Rs and Rp. The average in this case is about 0.024, or 2.4%. This means that at an angle of incidence of 45 degrees, about 2.4% of the light will be lost to reflection. The remaining 97.6% of the light is transmitted into the tank. Here's a graph to show the amount of reflection for different angles of incidence. Note that it stays below a few percent until extremely large angles of incidence. So, not to be a complete dick, but unless you actually know physics, don't claim to know physics. Link to comment
HecticDialectics Posted June 22, 2007 Share Posted June 22, 2007 Fair enough. I confused total internal reflection and thought it happens on either side on the boundary. Turns out it's only from a dense to lense dense media... :X <shrugs> edit: It is worth considering whether the angle of refraction very much past 45 degrees would ever make it to coral in the tank. Usable light would still substainally be reduced depending on how deep your coral is and it's location relative to the led... Thanks for clearing it up though. Link to comment
neanderthalman Posted June 22, 2007 Share Posted June 22, 2007 oh, I totally agree with you on the wide angle LEDs. You'll wind up with a significant portion of the light that doesn't even make it to the water's surface if the angle is too wide. This is a major inefficiency with other lighting types that tigher angle LEDs solve. This is how they can get higher intensities with less energy, because the light is concentrated into a small cone, not a sphere. Using wide angle LEDs removes this advantage. Link to comment
strangelove Posted June 22, 2007 Share Posted June 22, 2007 I'm wondering if the confusion with LED lights is that people are taking the specs one LED puts out and comparing them to the specs on one incandescent or fluorescent bulb. When most LED arrays consist of 25 LED's or more. Link to comment
coolwaters Posted June 22, 2007 Author Share Posted June 22, 2007 neanderthalman u totally lost me lol. it just seems at a 45 degree angle or more i start to see a lot of light reflecting off the surface of the water. from the chart you'll start to reflect 100% of the light at about 90 degrees? that means im still losing hella light... Link to comment
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