LED grow lights... input please.

[Opie Yutts]

Well, what I got out of that is they found x amount of light does the same thing as pulses of light that add up to x amount. How is that more efficient? The whole idea of pulsing light is to trick eyes into thinking a light is on all the time when it's not. Plants don't have eyes, therefore they will not be tricked, and when the light is off the plant knows it's not getting light at that point. Less light = less yield.

Opie Yutts Reviewed by Opie Yutts on 02-20-2008. LED grow lights... input please. Hello guys, I'm exchanging eMails with a representative from a LED company. I asked him if they could produce a custom light for growing, and here's what he told me: Our options are as follow: 940nm, 850nm, 660nm, 630nm, 610nm, 590nm 570nm, 530nm, 510nm, 470nm, 460nm, 400nm and a total of 64 LEDs in the bulb. Rating: 5

[SnSstealth]

I never quite understood that either. arent we trying to get the most photons possible to hit the plant. only thing i could figure is they're saying the plants could only take so much light at one time (kinda like a kid drinking a 2 liter...slowly).but I dont think thats right either. I realize solid state and all, but is turning on/off so many times going to hurt the leds?

Db:smokin:

[SnSstealth]

maybe i didnt quite get it, but regular photosynthesis occuring at 50mu, and it said in order to pulse and get the same effect, you gotta pulse them at 5000mu...so instead of long slow electricity usage you get super spikes every 200ms? wouldnt that strain the hell out of your equip? or maybe i need to read that paper again, minus a few bowls...heh
:smokebong:
WT

[Ziggy Stardust]

ROFLMAO! thats what kills me about this place. all ya gotta do is say it and it becomes gospel - just like jesus did! aint magic cool.

weve all seen pics reports graphs and tests at

Experiments with Hydroponics, Aeroponics, and LED Grow Lighting

proving that in veg stage HIGH POWER LEDs are the new way all that needs tweeking is the spectrum in flower and how long do you think it will take the slide rule guys to figure that out?. just dont waste your hard grown dollars on grossly UNDER POWERED kits your better off buying papers and bics and why are some of you always trying some kind of unproven slight of hand instead of doing whats proven to work do what works THEN little by little tweek...i mean unless youve got PhDs in things like botney energy flux and biology why try to trick anything?

right now the industry is responding to us the best thing is for us to interface with active testers and and lab guys to help them develop what we need visit greenpine look at the data read thier fourms and participate and contribute. we will get what we want faster. as it stands now both the main products UFO AND PSYCLON are being improved almost weekly and even then the manuf are open to upgrading our buys

Together
Everyone
Accomplishes
More
TEAM...get it?

[physicsnole]

so instead of long slow electricity usage you get super spikes every 200ms? wouldnt that strain the hell out of your equip?

Exactly right SnS. You overdrive the LED's for a shorter period of time. The LED's are fine with this, as long as they are pulsed for the correct duration so they dont burn out (Most LED sompanies give pulse time and rate for overdriving LED's). The paper proves that with 100us pulses, photosynthesis remains 100% of that with constant light. Were not trying to trick the plants by "flickering" the lights, merely providing increased amount of light over a shorter amount of time by overdriving them for 100us pulses.

but is turning on/off so many times going to hurt the leds?

LED's can turn on in 200ns. There is no harm done to the LED's by pulsing them, it actually increases life expectancy (if overdriven than life expectancy stays same).

Opie- Photosynthesis only happens so fast(but still very fast)...its not like the more light you give it the more it will grow(there is a linear relationship between amount of light provided and plant growth, up to a point). Plants require certain amount of photons per unit time to attain cellular reactions for light cycle, sugar creation, ect.

this is from the paper:
Much of the light used for photosynthesis by leaves within canopies is from sunflecks (Pfitsch and Pearcy 1989; Pearcy 1990). These sunflecks range from milliseconds to minutes in duration and their photon flux densities can be as bright as full sunlight.

So plants undergo photosynthesis naturally with these "pulses" of light.

Also from the paper:

We measured photosynthesis under light/dark times of 15/135, 7.5/142.5 and 1.5/148.5 us which required instantaneous pulse PFD of 500, 1000, and 5000 pmol mp2 s-', respectively, to achieve an intcgrated PFD of 50 pmol m-2 s ' .

Basically this confirms what you guessed Opie, that there is still the same amount of light reaching the plant by pulsing the lights at a greater power.

The photosynthetic apparatus integrates the pulsed light and uses it as effeciently as continuous light

Thus saying pulsed light for photosynthesis is just as effecient at continuous light.

So say we have 200 5W LED's (as my plans are). By pulsing them at a 10% duty cycle, the actual power used y the LED's is only 100W compared to the original 100W. However we are providing the LED's with more power (from 1000mA to approx 2500mA), so the power used would be approx 1/5 of the original, saving 800W of energy. The plants still received the required amount of photons for photosynthesis, but with way greater effeciency by pulsing the LED's.

Of course I do not take every word of this paper and assume it is true, I am merely showing how pulsing LED's could be used for greater effeciency. I created a simple 555 timer circuit and hooked up 7 LED's to it and pulsed them at the required specifications (100us on, 900us off, 5kHz), and recorded the power consumtion, and indeed there was an increase in effeciency (by that I mean less watts used by the LED's). The effeciency does not come from giving the plant less light, but form giving the LED's a smaller total energy consumption. Hope Im was able to clear some thing up without confusing anymore people.

Look at the top left of pg 265 of that site....nice graph showing increased photosynthesis with increased photon density (amount of light in the pulse).

[physicsnole]

Sorry for such a long post...didnt realize it would be so long...but still helpful info

[SnSstealth]

ROFLMAO! thats what kills me about this place. all ya gotta do is say it and it becomes gospel - just like jesus did! aint magic cool.

weve all seen pics reports graphs and tests at

Experiments with Hydroponics, Aeroponics, and LED Grow Lighting

proving that in veg stage HIGH POWER LEDs are the new way all that needs tweeking is the spectrum in flower and how long do you think it will take the slide rule guys to figure that out?. just dont waste your hard grown dollars on grossly UNDER POWERED kits your better off buying papers and bics and why are some of you always trying some kind of unproven slight of hand instead of doing whats proven to work do what works THEN little by little tweek...i mean unless youve got PhDs in things like botney energy flux and biology why try to trick anything?

right now the industry is responding to us the best thing is for us to interface with active testers and and lab guys to help them develop what we need visit greenpine look at the data read thier fourms and participate and contribute. we will get what we want faster. as it stands now both the main products UFO AND PSYCLON are being improved almost weekly and even then the manuf are open to upgrading our buys

Together
Everyone
Accomplishes
More
TEAM...get it?

hmm....isnt that exactly what me and doughboy are doing? And just to let you know, we are very much in contact with greenpinelane and HGL, so...
whiskeytango

[physicsnole]

SnS I think you should call your thread THE ULTIMATE LED TEST GROW...lol

[physicsnole]

This Light is purple right? This purple , which is in the 200-270nm of the spectrum, which is the ultra-violet to blue, Useful Radiation (PUR).

Hatch- UVB is outside the visible range of light, so it would have no color(to us but to the plants yes).

[physicsnole]

So Opie whats your opinion on pulsed lighting now? just wondering