what do you guys think of the new 660nm cree leds

What do you guys think of the actual efficiency of these new 660/670nm crees compared to the 630nms? With the increased photosynthesis rate would it be worth sacrificing efficiency with these?

660nm is the peak of chlorophyll A, but the main reason for including 660nm/670nm leds should be to maximize Pfr as a percent of total phytochromes.

No amount of 630nm light will get %Pfr as high as 660nm light can, sort of like no amount of yellow will make a human see blue.

%Pfr is like plant color vision. The higher it is, the higher "quality" or "color" it sees.

pedrovski said:

What do you guys think of the actual efficiency of these new 660/670nm crees compared to the 630nms? With the increased photosynthesis rate would it be worth sacrificing efficiency with these?

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churchhaze said:

660nm is the peak of chlorophyll A, but the main reason for including 660nm/670nm leds should be to maximize Pfr as a percent of total phytochromes.

No amount of 630nm light will get %Pfr as high as 660nm light can, sort of like no amount of yellow will make a human see blue.

%Pfr is like plant color vision. The higher it is, the higher "quality" or "color" it sees.

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Ok so correct me if i'm getting this wrong but if i'm getting what your saying, the more 660nm light the plant gets the higher the efficiency of the overall absorption of light to the plant? does 730nm far red not play a part in this? assuming your talking about the emerson effect or is the 730nm only real use a flower initiator?

Using 730nm with your other lights should cause %Pfr to fall as the R:FR ratio is lower.

pedrovski said:

Ok so correct me if i'm getting this wrong but if i'm getting what your saying, the more 660nm light the plant gets the higher the efficiency of the overall absorption of light to the plant? does 730nm far red not play a part in this? assuming your talking about the emerson effect or is the 730nm only real use a flower initiator?

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so thats a bad thing to have 730nm in a panel with lights on? i put some in my panel and plants looked to grow quicker but maybe thats because it influences stem elongation and blue counteracts that?

Good news, the specs are awesome!

pedrovski said:

What do you guys think of the actual efficiency of these new 660/670nm crees compared to the 630nms? With the increased photosynthesis rate would it be worth sacrificing efficiency with these?

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let me no what u pull from them also the light system looks verry messy for me cords and shit hanging every were but i hope it works out well for u let me no what u pull

I really want these now. The problem is that running them at such a low current means I would need like 70 of them. If cree could just put 70 of those in series in COB form, that would be fantastic.

SupraSPL said:

Good news, the specs are awesome!
View attachment 3206432

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True, it is a bit of work to use them on a large scale.

rob333 said:

let me no what u pull from them also the light system looks verry messy for me cords and shit hanging every were but i hope it works out well for u let me no what u pull

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i know my wiring is a little on the messy size i was planning on building a small aluminium ballast to put the lights on that way will be able to keep tidy and keeping power supply outside tent and currently experimenting with 2 autos a bubblegum and a white widow in small hempy buckets using biobizz nutes so not expecting too much from them tbh but i have got a c99 vegged for just over a month which i have topped MANY times will flower once autos finish this will be the test of how well the lights work as i have only had the cree lights in the tent for 1 week of the 2-3 weeks they have been budding before that was just 2 of my custom built panels using about 70 actual watts each, the cree panels are also running about 70w each should be proving more than enough light but think i will sell on some of my panels after the c99 to get some with these 660nm cree leds

So i am thinking of building a panel with 100 of the new 660nm crees and 100 cree-xte-5w in white. Should i mix in some blue as well? What kelvin is a safe bet for the whites?

Hey amigo, if you have not ordered the XTEs yet, I would encourage you to look into the small Vero COBs. They are a lot cheaper per watt and a lot higher efficiency than the XTEs. Lots of choice for color temps and drive currents. Is it a veg panel, flower panel or both?

Wow thanks Supra.

I have not heard of the vecros...i am looking into them now and they seem like the shiat.

Is mostly a flowering panel. Would you still go with the cree 660s? Which vecros would you mix with them?

Gotcha, for flowering I would recommend the Cree CXA3070 3000K or the Vero 29 3000K. You could add deep blue and deep red but not necessary to do it unless you like to tinker.

So Photo Red aren't needed if 3000k is used?

Castaman said:

So Photo Red aren't needed if 3000k is used?

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I haven't seen a side by side comparison yet.

I would like to run some photo red and 6500k xp-l to compliment a pair of cxa-3070 AB 3000k in my next build. The cobs are already on dimmable drivers and I would like to run the xp-l's and reds on dimmers too so I can try and find that perfect spectrum.

Can you overdrive the cree photo reds? I've seen flashlight mods that push xm-l2's over 5 amps. I wonder if you can run them up to 1400ma if you don't expect major longevity.

churchhaze said:

660nm is the peak of chlorophyll A, but the main reason for including 660nm/670nm leds should be to maximize Pfr as a percent of total phytochromes.

No amount of 630nm light will get %Pfr as high as 660nm light can, sort of like no amount of yellow will make a human see blue.

%Pfr is like plant color vision. The higher it is, the higher "quality" or "color" it sees.

Click to expand...

and why is it so important to have a high Pfr ratio in flowering ?
instinctively I would tend to do the opposite with 730nm, since the stretch is over
I believe a 680nm led, while having a similar photosynthetic effeciency than a 660nm and not acting on phytochrome state, would make plenty of sense in flowering ...

by the way there's an old theory, called Photosynthetic Artificial Darkness, or Rauber enchancement, where he was mesuring the equivalent duration of different spectrum compared to a basic darkness ... he came up with a strange lighting schedule, that I wouldn't bother trying, still ...
if I understand his paper correctly, a 660nm could prevent flowering if used in high ratio ...

Devildenis69 said:

and why is it so important to have a high Pfr ratio in flowering ?
instinctively I would tend to do the opposite with 730nm, since the stretch is over
I believe a 680nm led, while having a similar photosynthetic effeciency than a 660nm and not acting on phytochrome state, would make plenty of sense in flowering ...

by the way there's an old theory, called Photosynthetic Artificial Darkness, or Rauber enchancement, where he was mesuring the equivalent duration of different spectrum compared to a basic darkness ... he came up with a strange lighting schedule, that I wouldn't bother trying, still ...
if I understand his paper correctly, a 660nm could prevent flowering if used in high ratio ...
View attachment 3531207

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I'm curious to as i just bought some 660 to play with but i have seen people use these lights and they seem to have a lot http://rollitup.org/t/testing-osrams-150w-horticultural-led-fixture-v1-monochromatic-dream-or-nightmare.867782/

Devildenis69 said:

and why is it so important to have a high Pfr ratio in flowering ?
instinctively I would tend to do the opposite with 730nm, since the stretch is over
I believe a 680nm led, while having a similar photosynthetic effeciency than a 660nm and not acting on phytochrome state, would make plenty of sense in flowering ...

by the way there's an old theory, called Photosynthetic Artificial Darkness, or Rauber enchancement, where he was mesuring the equivalent duration of different spectrum compared to a basic darkness ... he came up with a strange lighting schedule, that I wouldn't bother trying, still ...
if I understand his paper correctly, a 660nm could prevent flowering if used in high ratio ...
View attachment 3531207

Click to expand...

What I meant to say was that if you do want to increase Pfr, you should use more 660nm rather than using a "Warmer" white. I personally think 660nm makes more sense in veg, but I haven't even used 660nm leds so I can't draw any conclusions. The best evidence I have is whenever I see side by side tests of HPS vs blurple, the plants under blurple are much shorter.

I've been thinking of adding some 660nm leds to my veg lamps.

okay we're on the same page here,
I've played with 660nm in my flowering room during these last year, tried some weirdo time schedule ...
finally can't tell a difference in final bud aspest, g/w ... except for the morphological part, if you have stretch issue, they are the solution
just made a 5000k + 660nm veg lamp, can't tell much after a week of grow ... expecting big roots