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Thread: LED what bin ?

  1. #11

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    Quote Originally Posted by kerry View Post
    These are red and are not rated in the "K" scale. Mine are just plain old 660nm (nanometers). This is just like a color that you would see when a light source say of 6500K is refracted through a prism. The prism refracts a light pattern like a rainbow, my LED's are in the red spectrum that is displayed through the prism. Check this site it might help a bit. http://www2.chemistry.msu.edu/facult...s/spectrum.htm . Just google "660nm 3W LED" and a lot of places will come up in your search.
    i'm using the XML's becuase they are the most ligh for the watts. and becuase really cant any other stuff I found some 10w an 5w reds but thos gota be tro strong.

    the old cree's seem like they waste lots of power for the light you get.

    http://www.mouser.com/Search/Refine.aspx?Keyword=660nm

    i hope that works, there are a few options there

    like
    [LedEngin LZ4-40R200]

    897-LZ440R200

    LZ4-40R200
    LedEngin High Power LEDs - Single Color Deep Red 660nm Data Sheet 75
    In Stock
    More Info Available

    ^ thata 10w led (really 7.5: 700ma at 10.5 volts)

    but i have not heard of these before

    http://www.mouser.com/ProductDetail/...HvczxJuGP5FfBw

    that one claim 5W but its on 2.5v @ 1amp = 2.5W

    my question is, what xm-l BIN is the in the 660nm area? it should be around the 2700K area. I know one is really "light temp" and once is wave length.

    one of those bins for xml have to be close (see the warm chart in page 7 on my first link above) i have found the xm-l for 5-8$ each on website around the net.

  2. #12
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    Quote Originally Posted by turbo v6 camaro View Post
    my question is, what xm-l BIN is the in the 660nm area? it should be around the 2700K area. I know one is really "light temp" and once is wave length.

    one of those bins for xml have to be close (see the warm chart in page 7 on my first link above) i have found the xm-l for 5-8$ each on website around the net.
    The answer to your question is none. There are no white LEDs that put out any large amounts of 660nm light. They all drop off in spectrum before they hit 660nm, even warm white LEDs. It doesn't matter how many watts, lumens, or PAR output a white LED puts out, bottom line is at least 75% of the light that is emitted from a white light source is going to be wasted light, in turn being wasted electricity, when trying to grow algae. You would get much more growth using 1/5th the wattage and using the correct spectrum (1w 660nm LED vs a 5w Cree XM-L).

    These are the most recent LEDs I ordered. I got both 640-650nm and 650-660nm. Price was $1.80ea. They are from China though, so you have to deal with everything that comes with that (language barriers, lack of support, having to order 100 pieces minimum, etc).
    http://www.fd-led.com/productinfo.php?id=108

    For smaller orders I stick with RapidLED and go with the OSRAM 660nm LEDs which are high quality. Great place to buy from IF you live in the states.
    http://www.rapidled.com/servlet/the-...-3W-Red/Detail

  3. #13
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    I guess if you had to put the "K"rating to it it would be about 1800K but I do not know how accurate it is. Also those specs you see on LED's are not accurate so take those with a grain of salt. Also note that I was unaware of CREE making a 660nm LED. I would check OSRAM 660nm if you want someting that is more expensive. I will tell you that my china ones from eBay produce as good as the Osram I bought from rapidled.com do. Look on eBay there are a lot of them on there, even quantity discounts.
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  4. #14

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    Quote Originally Posted by Ace25 View Post
    The answer to your question is none. There are no white LEDs that put out any large amounts of 660nm light. They all drop off in spectrum before they hit 660nm, even warm white LEDs. It doesn't matter how many watts, lumens, or PAR output a white LED puts out, bottom line is at least 75% of the light that is emitted from a white light source is going to be wasted light, in turn being wasted electricity, when trying to grow algae. You would get much more growth using 1/5th the wattage and using the correct spectrum (1w 660nm LED vs a 5w Cree XM-L).

    These are the most recent LEDs I ordered. I got both 640-650nm and 650-660nm. Price was $1.80ea. They are from China though, so you have to deal with everything that comes with that (language barriers, lack of support, having to order 100 pieces minimum, etc).
    http://www.fd-led.com/productinfo.php?id=108

    For smaller orders I stick with RapidLED and go with the OSRAM 660nm LEDs which are high quality. Great place to buy from IF you live in the states.
    http://www.rapidled.com/servlet/the-...-3W-Red/Detail
    okay i see what you are saying, i like the 48v control they have on rapid LED also i'll look around some more

    i wish they would just rate all by nm and K so you know what you are buying

  5. #15
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    That really isn't possible to have just K or nm, they are 2 different things. Kelvin is confusing to me because it seems arbitrarily made up, nm is simple and easy to understand, although hard to use when trying to describe a light that emits multiple spectrums. Instead of saying 2700k light you would say "some 450nm, more 500nm rising up to 600nm and sloping down quickly after that".. 2700k rolls off the tongue a lot easier. LOL.

    What does the Kelvin rating of lighting mean?
    The Kelvin rating, abbreviated K, refers to a guage of the spectrum that the lighting emits. Kelvin is a unit of temperature and is related to degrees Celsius using the following conversion K = oC + 273.15. The rating is based on the spectrum that a perfect blackbody emits when heated to a given temperature. Therefore, a bulb rated at 10,000 K means that it emits a spectrum that is approximately like that of a perfect blackbody heated to 10,000 K.

    It must be remember that these ratings are very approximate, since a metal halid and flourescent light emit light in discret bands, it is not a continous spectrum as would be emitted by a perfect blackbody. So two different lights that are giving the same K rating can look very different to the eye.
    I understand the confusion when your just learning about how lighting works though. Light waves are measured in nanometers, nm for short. The number is the distance between the waves from peak to peak, like measuring the distance peak to peak between waves in the ocean, except you would use meters for the ocean instead of nanometers for light. The visual spectrum, what we see with our eyes, is usually around 400nm (deep purple, near ultra violet which is below 380nm) and up to 700nm, almost infrared. Purple light is around 400-440nm, blues go from 440-490nm, greens from 490-540nm, then yellows 540-580, oranges 580-620, and reds in the 620nm-700nm range.

    When talking about different light types, especially in regards to LEDs, it is either a monochromatic LED (puts out only a very narrow band of light, usually in blues, greens, or reds) or broad spectrum LEDs, which are your various white LEDs. With a monochromatic LED you get a flat graph with a giant spike in one small area of the light spectrum, with broad spectrum LEDs you get a spike in the 455nm range and also a large bell curve ranging from greens to the lower reds and then dropping off in intensity.



    Coincidentally the same 400nm-700nm is also considered the "PAR" spectrum which is the range that a PAR meter will test. PAR means Photosynthetic Active Radiation, which basically means "how intense is the light I can see with my eyes". The human eye is a terrible tool to measure light intensity with, which is why we use Lux meters for general lighting. For our hobby using PAR is slightly better than Lux, but really not by much. People put a lot more into PAR that what it really is, which is just the intensity of the light, it tells you nothing of the quality of the light, that part you have to know ahead of time to accurately understand the reading a PAR meter will give you. You can have 2000 PAR and not grow anything because it is not in the spectrum used for photosynthesis, or you can have 100 PAR in all the right areas and have fantastic growth. The spectrum of the light plays just as important of a role in the overall lighting picture as the intensity of the light.

    So that covers general light. Now we get into photosynthesis with light. We already know what specific spectrums of light are needed in order for photosynthesis to work. For the vast majority of photosynthesis it boils down to 4 different spectrums. 430nm, 455nm, 640nm, and 660nm. For sheer growth of algae, the various Red LEDs (630nm-660nm) will provide that without problems. Those are the major spectrums, there are a lot of minor spectrums as well when it comes to photosynthesis. Actually most of 400-500nm range light is used to some extent as well as most of the red spectrum. Here is a chart that shows the light spectrums used in photosynthesis, also known as PUR, which is Photosynthetic Usable Radiation, which is self describing, it is the usable part of the light spectrum vs the overall light spectrum. If you look at that picture, then look at the white LED chart above (where cw=Cool White LED, nw=Neutral White, ww=Warm White), you can see once you hit the 500nm point, the white LEDs are almost exactly the opposite light spectrum needed. The white LEDs have a majority of the output/intensity in the green-orange colors, which are exactly the least used of the spectrum. This is kind of a general "PUR Table" that has been smoothed out (there are small gaps in the blue and red spectrums that are not used which isn't pictured), but everything photosynthetic will vary slightly due to numerous factors/adaptations.


  6. #16

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    i'm more use to the K values as i do photography in my free time :P thats where its used alot google photography white balance

    thanks for the good post I will post back we i think a have a kit together here in a few days

  7. #17
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    Quote Originally Posted by Ace25 View Post
    As far as LED per cm2.. I would say from my experience that 1 LED (3w style, running at 2w) can cover an area up to 4 cm2 but ideally you would want to stay under 3 cm2. That is my guesstimate on what red LEDs will cover and still give you good growth.
    Ace, I'm curious how you came up with this number. 1 3W LED @2W covering only 2cm x 2cm (4 cm^2) seems really low to me. Most of the 3W builds I've been looking at recently look like they're using more like just a couple 3W 660s to replace an entire T5HO 24" lamp. Just checking to make sure I wasn't missing something

  8. #18
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    Ah, I see what I did there, I made an assumption, and I was wrong. I somehow assumed 1cm was close to 1in, when in reality it is closer to 1/2in. So double the numbers for cm. I can't believe it took this long for someone to see my mistake. Good job calling it out though so it is corrected. I would rather be called out and proven wrong vs people using bad information. So 1 LED will cover up to a 4"x4" square @ 2" distance. If you move the LED back further, it will cover more area but will not be nearly as intense in output.

  9. #19
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    1" = 2.54 cm.

    So you meant that 1 3W LED @2W is only enough to cover a 2.5" x 2.5" area adequately? Still seems like that would be a lot of LEDs.

    For example, using the screen I run, which is 20" x 6" or 160 sq in, I use 2 x 24W T5HO. Going by the "1/4 the wattage" that I've seen several people post, I would think that I would only need 48 / 4 = 12W of LED, which would be 6 @ 2W each, and that breaks down to 120 / 6 = 20 square inches per LED, or about 4.5" x 4.5". So when you said 4 cm2 did you mean 4 x 4 or 4 square cm?

    See where I'm getting confused?

  10. #20
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    I mean 2 x 24 on each side, so then 6 LEDs on each side...

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