LED Musings

This is very preparatory stuff but (very) basically am i starting in the correct direction looking at the CREE XR and XR-E Red and Royal Blue lamps LED's as here:

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0376124
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0517955
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0376118
http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=6675461
or
http://www.luxeonstar.com/Red-626-nm-20mm-Tri-Star-Rebel-255-lm-p/mr-d0040-20t.htm
http://www.luxeonstar.com/Red-626-nm-20mm-Tri-Star-Rebel-255-lm-p/mr-d0040-20t.htm

Grabbing an old PC power supply, lets say 400w. Working out correct value resistors and then maybe implementing switches between red and blue strips to make it more efficient in different stages. Making sure everything is sufficiently sinked and cooled of course.

It can't be that simple can it?

Christ actually i wish it was that simple after really looking into what i'd need and checking other forums (candle power for instance) no one can really seem to agree on anything wavelength wise, no one is too sure whats best for what really, or which is most efficient. I think i'll not bother upgrading from a million cfls until theres some real definitive science i can read and apply myself with my own LED's. its a minefield of mass miss information...

Hey randomlygrow, I too am looking into a panel like this built with high power LEDs. First off I want to say, if you're going to use CREE LEDs, you might as well use the XP-E series, has all of the wavelengths you may want and it's the strongest available LED CREE offers.

It is really rather simple if you don't use resistors. Use an LED driver, they regulate the current going into the LEDs so there's no chance of them frying due to current. They make them in 350mA, 700mA, and 1A. Resistors are bad since they turn excess current into heat. This is exactly what you DON'T want. All you need is your series of LEDs connected to the driver, and the driver connected to your power supply.

Currently I'm looking into making a panel that will be run by the Luxeon Stars. I chose these because there's actually a grow out there that a smart guy did that shows the potential of these LEDs. His grow can be found here. I am also choosing these LEDs since they come on the star when you get them. You don't have to go through the hassle to mount the 3.5mm x 3.5mm die to the star. That is the case with the CREE LEDs. On paper the CREEs look better but they're just too much of a hassle for me.

As for the wavelengths you need, I found an article on here(can't remember) but I copied down all of the wavelength info from it, since most of the article was pointless. From what I've found, the crucial wavelengths are 662nm, 430nm for chlorophyll A and 642nm, 453nm for chlorophyll B. I have also found that a wavelength at 612nm(orange/amber almost) will assist with carotenoid production. I have also read, but not seen proof, that IR light is useless for mary jane. And as for UV, only UV-B will assist with THC production. The wavelengths for that are 320-290nm. LEDs at this wavelength..I have yet to find. They just don't make them yet. If you want the UV-B for THC production you'll have to get a tanning or reptile light.

One thing you'll need to be aware of. LEDs need excellent thermal management. We're talking a nice heavy duty heatsink and some fans to cool it down. Each LED should have 1 square inch of surface to dissipate heat AT A MINIMUM. LEDs are much more efficient at lower temperatures. If you can find a way to dissipate the heat correctly, you will get much more usable light out of your LEDs AND they will last a lot longer.

You can check my thread in the DIY section, you may find some useful info there as I have done many hours of research into a panel just like this.
If you have any questions feel free to send me a PM or just reply, whatever works.
Good luck!
-crunk

Yeah i saw your thread man, its all very interesting, but there is a lot of **** out there it seems. I don't feel its worth the agro just yet. Maybe next year, although people seem to have been saying that for 3 years at least! Your wavelength stuff looks good, the problem seems its all compromise, because LED's don't produce exactly what we want which doesn't make them as super efficient as we'd like. Then there's the far red debate, which may or may not be absorbed and help for flowering, but may promote absorption from the red LED's.

I think they don't seem bad for starting and vegging but flowering isn't quite sensible yet, which is a shame. Ive no doubt it'll get there some time in the future but for now its not totally viable in my mind from start to finish without a little help, if you want decent yields anyway...

They're basically not cheap and not totally effective, if you want affective you choose HID, if you really want cheap you got CFL. That's the way i see it right now, until LED's get even cheaper they'll start competing with CFLs in custom/micro grows and the energy concious user...