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11-18-2013, 08:40 PM
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Senior Member
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Join Date: Dec 2012
Posts: 753
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Quote:
Originally Posted by DavidCampen
I am skeptical.
I use these LEDs:
LED Engin
Reds can be driven at about 10 watts and blue and white at 15 watts but each package is actually a cluster of 4 diodes. I buy then surface mounted on a Metal Clad Printed Circuit Board (MCPCB) with the 4 LED chips already configured in series. You can buy them from Mouser for around $10 - $15 in single unit quantities.
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Thanks David, but these are 6-8 times more expensive than the ones directly from China (Mouser's are also chinese). And it costs me less to ship them from China than from the US. I'll see how they work out; I'll do a step-by-step photo/video blog.
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11-19-2013, 02:51 PM
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Join Date: Nov 2010
Location: Southern California, Los Angeles
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Quote:
Originally Posted by ALToronto
Thanks David, but these are 6-8 times more expensive than the ones directly from China (Mouser's are also chinese). And it costs me less to ship them from China than from the US. I'll see how they work out; I'll do a step-by-step photo/video blog.
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Yes, if you apply appropriate quality control measures you can get stuff from China that meets specifications.
This is what large vendors like the companies who supply products to Mouser do. If you don't do quality control testing it is likely that you will get stuff that comes nowhere near meeting the claimed specifications.
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11-19-2013, 09:22 PM
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Join Date: Apr 2012
Location: Paris
Age: 57
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Deep red is 690 nm, not 730. It's near IR, not IR-A.
On the mix itself there's solutions, for the whites, it's more ~6500K and ~3000K you'll find in exemples.
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11-21-2013, 03:49 PM
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Join Date: Apr 2012
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Location: Fairbanks, AK
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Quote:
Originally Posted by DavidCampen
I am skeptical.
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Alla is probably talking about something like this:
500W Integrated High Power LED-LED plant lamp
It's not a single diode, but a COB-type. For the lower wattage COB LEDs (e.g. 30-50W), people seems to drive at the wattage close to the max-rated W, but I don't know about these monsters.
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11-21-2013, 04:53 PM
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Join Date: Apr 2012
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I can't access you link naoki… is it working for you? (I've tried the domain name itself to no avail too)
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11-21-2013, 06:16 PM
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Yes, the Chinese manufacturer I contacted sells these COB diodes as well. I wasn't seriously considering a 45,000 lumen monster. I imagine it would be used for a highway lamp or a movie light (to imitate sunlight during a night shoot).
However, I think that the 5W LEDs I'm ordering are individual diodes with heat sinks attached.
I'm making a grow rack with 2 shelves and a light canopy; and the upper shelf will have a canopy built in underneath it. The shelves will be heated; I just hope it all works. I poured them all today; the sides are made, so it's just a matter of unmolding the shelves and canopy, and assembling the whole thing.
So the LEDs will be attached to aluminum sheets and suspended inside the canopies; the driver(s) will be outside of the grow areas. The footprint of each shelf is 85x55 cm (about 33x22"), so the LED sheets will be only a little smaller than the footprint. I figure 50W/sheet will light up the shelves nicely.
Now I have a question: should I bother with far red at all? Naoki had stated earlier that a combination of cool and warm white would provide enough radiation at the blue and red ends of the spectrum, yet in another thread, he extols the virtue of his blue/red LED fixture... Hmmm...
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11-21-2013, 06:56 PM
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That sounds like a fun project! "pouring" means that you are making the shelves out of concrete? Isn't Aluminum (or copper) plate of that size pretty expensive?
Well, I used to be a big fan of R+B grow lights, but the technology changes, and also I keep learning new things (from scientific papers and people here). It seems that the white emitters has been improving steadily, so PAR efficiency of white LEDs may be close to or better than R+B grow light. I can't quite get the real numbers to make the direct comparison, but one of the pdf file I linked in one of the thread (comparing LED vs HID) seems to suggest this. This is a part of the reason that I'm starting to play with white LEDs (Ray's W+R, Cree 9.5W household bulbs, and incoming 30W COB).
I wouldn't use FR (730nm) since I haven't found strong evidence that it is beneficial for most orchids.
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Post Thanks / Like - 1 Likes
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11-21-2013, 10:09 PM
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Join Date: Apr 2012
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It's ok naoki, it must have been my wifi access, I wasn't home. It's fine at home.
730 nm in IR-A, NOT FAR RED, Far red is 690 nm and is beneficial to chlorophyl A. There's a big absorption point here.
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11-21-2013, 11:07 PM
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I suppose you could call it a 'fun project'. It's how I push the limits of my company's capabilities and try out new products. In this case, it's embedding heating cable in a shelf with a built in spill tray, all completely waterproof. I've made unheated shelves like this, so this just takes it a bit further.
As for the LEDs, I'm also trying to develop living walls as a commercial product, and correct lighting is one of the biggest challenges in making these walls survive. Completely customizable, lightweight and unobtrusive lighting would provide the best solution.
Martien, thank you for the advice on far red wavelength.
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