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If I remember correctly, whole China goes crazy when the year changes, so it might take some extra days for goods to arrive at this time of the year. Good luck with the project, keep us posted!

Sweet looking rig for sure. :wink:

Nice setup with the fluorescent lights! How far apart are those tubes from each other?

I know nothing from growing lettuce, but longer photoperiod would be an economical way to achieve higher DLI with lower equipment costs. Following sources might provide some insight too: http://europepmc.org/abstract/MED/11539771 http://hortsci.ashspublications.org/content/33/6/988.short

PPFD x hours x 0.0036 = DLI Using 24 hour photoperiod, you would need 200 micromoles for PPFD to achieve 17 mol DLI. 130 lumens/watt with vero or cree leds converts to roughly 1.8 to 1.9 micromoles/watt/s. 1 square meter is roughly 11 sqft, so 18 micromoles/s per squarefoot for flux. So...

Not worth the effort mate, sanding that much stuff is PITA by hand and they are very hard to get totally flat. If you have access to a mill then why not. I had those same style heat sinks, btdt.

Bravo Mr. SDS, excellent thread once again and absolutely the best explanation I have seen so far on the subject! Knna would approve too :) One question though regarding the CXA and white leds in general, isn't there a shift in the spectral distribution with varying drive current/voltage/tJ...

Reflector losses, penalty from non-uniform irradiance, penalty from a small point source light source leading to less diffusion(?) etc. It's not only the raw theoretical numbers that dictate the difference between HPS and LED imo :) ..in a very optimised setup where photons are taken up...

Those Mean Well's should go a little over the rated voltage AFAIK, there's an over voltage shutdown listed in the spec sheets. Someone with experience could confirm, but I think they'll be fine running a little overvoltage - current might just sag a little.

10z from that kind of an area is very respectable number! Pretty much only guys I know doing better are crazy dutchmen with perfectly controlled climate, multiple Gavita 1000 Pro DE and Co2!

No idea honestly, EU based company and I suspect that they are very expensive professional equipment mostly used in scientific experiments.

This is a very complex subject and B/R lights work surprisingly well, especially in limited circumstances of micro growing. But yes I think, when going for the best quality and unlimited resources, I think B/R lights suffer. That was not any news tho, was it? :) edit: Just wanted to add...

http://valoya.com/products#r-series Dunno if they pass US standards tho..

There is only so much surface area to saturate, but if you go deeper... Intensity has everything to do with the usable spectra.. :) Let me just leave these here too. http://www.plantphysiol.org/content/155/1/108.full Leaf Functional Anatomy in Relation to...

Nice explanation! Agree with everything, just small nitpicking :) 3ftx3ft = 0.827225 square meters therefore 4 x 283 umol/s at 3x3 = 1368 PPFD

And whats that, like high 70's low 80's in efficacy %? Hello 3+ GPW in the future :) ..only takes 10 to 15 years at this rate to get those buggers to the market..

I kind of dislike this thread, but what the hell, here goes nothing: Intensity I don't recall seeing anyone running leds at 50+W/sqft. Let alone top bin DIY driven softly. Scale Most of the led grows you see are on micro level, small plants = small buds Efficacy Almost all grows posted are...

Very informative graphs, thanks guod! I don't know where I got that 10% figure, now that I checked with http://pct.cree.com/dt/index.html I got about 7% and 8% for XPE and XPE-2 reds. CXA3070 @ 1A was less than 3% difference.

Hi Mellodarama! Yes, you are absolutely right. I used this Cree calculator for my numbers: http://pct.cree.com/dt/index.html

Cool project! I like the idea of those veg units, with light traps those could sit in the corner of a flowering space too.