10w LEDs

A

Anonymous

I got some 10w LEDs, 9 20k and 9 blue for a tank I'm setting up. I ordered the LEDs from china on eBay. I also got 3 12v 5a max power supplies. The lights are 9v 1000ma. So I got 3.3ohm 3w resistors and wired 6 lights per supply with a resistor wired to each. Ive actually got less than 12v coming from the power supply to run fewer amps to help control heat. The 6 lights parallel are only running at 3.5A well below their max rating. I can't see any visual intensity change from running lower voltage. So the whole set up cost about $200 maybe $220 wires and all. I'm wondering why I don't see anyone else doing anything like this? My tank isn't set up yet so I've got no idea how well corals will do. Trust me I'm dying to find out.
 
We aren't doing it yet because we are waiting to find out how it works for you! Whatever you do, don't look directly at those laser beams!!!!!!!!! And don't let any children, pets, friends, relatives get in a place where they can inadvertently look at them! They can destroy vision very easily. They say not to look directly at even the low wattage LEDs, so those are much more powerful, and dangerous, I would expect. I'm sure that you know that, but it bears repeating, I think!

David
 
No spectrum info, no par ratings, no success stories being discussed. Until people try it and succeed many won't give it a shot. A new tank it's a great place to try it! Keep us updated! Oh... I need pics!
 
I'll get some pics posted in a bit. I'm sure any electricians that see what I've done are gonna say "See, that's why allowing the general public to buy soldering irons at radio shack is a bad idea!"
 
I used a piece of thin birch paneling to mount everything on. The power supplies are mounted on top with the 120mm pc fan in the middle. The fan blows air up drawing it into the holes around the sides. You can see the 10w LED's are mounted heat sinks, believe it or not they don't get more than warm as long as the fan is running. I built a 2 part canopy, the bottom is basically the bracket to hold the top, and the top has a piece of glass siliconed into it to prevent any evaporation from getting to the lights. When everything's put together the glass sits about 3-4" off the water and the LED's sit about 1.5" above the glass. I still don't have any water in the tank yet but the dry run looks really nice. Maybe once I've got everything up and running someone with the know how and equipment can measure the spectrum and par of the lights, I wouldn't even know where to begin (I'm sure there are many threads about it)!!

As for looking at them directly I know better. Even looking at them in the reflection off the bottom of the tank is pretty bright. The reflection off the back glass of them off the bottom of the tank is how I look at them. Apparently there's a condition called blue light blindness which causes the destruction of the nerves just in the center of your field of vision and I see how it could happen. Even a quick glance leaves me seeing spots.
 
Cool project! You're running them at about 60% of their capacity if I understand your circuit correctly. There are power supplies designed specifically for this type of application that could get you to 100% with less heat output and probably a dimmer function to boot. I bet the same people that sold you the lamps could hook you up.
 
Yeah they are running at about 60%. The power supply's voltage is adjustable and I can turn the voltage up. When I do this tho the current jump is huge and I don't see any increase in output, just heat. Once I got them wired up I toyed around with the voltage and I basically tuned it just slightly above where it seemed like they were at max output. I could see a power supply being able to cut out the resistors completely but the heat from the LED's would still be there. It's been a learning experience for me. If I run them at 1000ma instead of 600ma they get really hot and my set up wouldn't work, the wood panel would have to be replaced with a large piece of heat sink material. The heat from these suckers cranked up is really high, but again I really don't see an increase in output.
 
Yeah, make sense. Heat is always the problem in this hobby, lol.

Running LED's without resistors requires connecting them in series and using a constant current source supply. You basically set it to deliver a constant 1 amp at whatever voltage is required to do so. The reason it's hard to do this with a ccv supply like you have is because there is no feedback mechanism. The knee voltage for each lamp is different and varies a lot with temperature. When you edge over the knee, the current will jump way up quick as will heat output.

Something like this would work for a three-led link: http://www.trcelectronics.com/roal/rsld035-09.shtml

I'm sure there are some china knockoffs on ebay for cheap.

As far as brightness--that's completely subjective. The human eye is actually quite bad at judging illuminance (far less so PAR)--especially with unnatural spectrum like artificial lighting. None of this matters if you're just going after aesthetics, but if your aiming at doing some PAR/watt/heat comparisons (we hope [smilie=lol.gif]) against conventional lighting then you'll probably want to find a ccs supply.

BTW, the club has a PAR meter for members, I think. I do as well.

Hack on!
 
Just for reference when you are ready to test readings on them you will need a LUX meter as PAR is not an accurate measurement of LED output. I do believe the club has one as well.

Sent from my MyTouch4g
 
Apogee meters underestimate blue, but it would be by the same amount for any light source so you could still do valid comparisons--if you think PAR is a useful metric for corals, that is. I don't think red above 650nm is significant with most available light sources, LED or otherwise. The same issue would exist with a lux meter except that the spectrum would be even more inappropriately weighted than with an apogee. I hear the licor's have the best response, no idea how much $$$ though.

Interesting though, maybe there's more to the story. I'll have to bounce this back to apogee and see what they say.
 
I think it's best to not try to compare numbers, but rather compile your own research with your own corals and your own meter. I can put three frags in my frag tank and see which one colors and grows better at different levels. Then move that piece to that same light level in my display to get the best color from it. Other than that you're really looking at general output, which is all you really need. Don't worry about which meter you get... who cares... just put it under a trusted light source such as a 250w MH and then under yours and compare numbers. It won't be measuring exactly what output the chloriblahblah needs but rather this fixture vs that fixture. Almost counts in horseshoes, hand granades and (in most cases unless your spectrum is just WAY off) light sources.
 
How big is your tank and why would you want to run 10watt LEDs from the pics seems like you have a small tank and seems like a bit of overkill if it is a small tank and I personally wouldn't of used wood it is a bad conductor of heat if anything it is gonna make the leds run hotter as it cant dissipate the heat and lessen the life of them.


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The tank is 20x20x20 so 39 galish. I tried to find some good output comparisons of different size LED's vs MH and really couldn't find a whole lot. It might be overkill but if they're too bright I can turn them down. I agree wood probably isn't the best choice but it's so cheap and easy to work with.
 
It's going to be alot of light but you should be able to acclimate SPS and higher light corals over time. I've seen a 20g with a 400w Iwasaki, I personally have a 58 w/ a 400w DE and 4 PAR 38. Just be slow in moving things up and you should be fine. Those are powerful LEDs but without optics the par/lux shouldn't too much. If it is you can always move the fixture up.
 
Just FYI on general going bigger in LEDs doesn't always mean better 3 x 1 watt LEDs are more efficient than 1 3 watt led from my research in leds


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@AdamT wrote:
I'll get some pics posted in a bit. I'm sure any electricians that see what I've done are gonna say "See said:
LOL. I used to tweak and build DIY audio amplifiers. If it makes you feel better, I designed one where I did not correctly calculate the bias voltage and the components got so hot the solder just melted off the leads on some TO-3 cased output transistors.
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