LED Companies w/ LINKS

[Perro Negro]

According to our data on
C. sativa, temperature optima for PN was observed at 30 C.
In general, temperature higher than 30 C had an
adverse effect on PN (Fig. 1A). At 25 C, rate of
photosynthesis increased with increasing PPFD, but this
trend peaked with 1500 μmol m-2s-1 PPFD at 30 C, and
decreased at higher light intensities.

stolen from
Photosynthetic response of Cannabis sativa L. to variations in
photosynthetic photon flux densities, temperature and CO2 conditions

That is a great article. I wonder how different it would have been if they had used a Model LI-6400-02B; light emitting silicon diode;LI-COR instead of the Model LI-6400-02?

The spectrum used was bad at best but at least it is consistent. We all seem to agree that a better spectrum would allow a plant to handle more PAR so it would be great to have this gear and test it with different grow lights as the variable.

 

[Eraserhead]

Yeah, that is true, lots of exaggerated footprint claims going on, or inflated claims on how it compares to HPS...

I judge footprint on a couple things, not just the wattage of the panel. The most important thing is panel shape and size. The smaller your panel is, either it's the higher it needs to be to cover its intended footprint, or a lesser footprint. And the further away the lamp, the more efficiency you're losing. I try to stay within 4"-6" of the smaller panels perimeter, meaning if the panel is 11"x11", it would cover 20"x20"-23"x23", and for 110w, that is about right, giving 30-40w psf. The light doesn't have far to travel before hitting the plants, thus preserving its efficiency. That particular light still gets about 1020 Umol'/s at its center @ 12", so it still needs to be about 14"-16" to get optimal PAR.

Lights that will cover 4x4, what amounts of light that hits the edges of the 4x4, would be dependent of beam angle and intensity of the LEDs. Narrower the angle, the smaller the footprint, and lesser PAR at the edges. The wider the angle, at the edges, it will still be low, because anything beyond 90° disperses and spreads out too fast.

Here's the Heliopto page with all the data sheets http://www.heliopto.com/files/

They're updating their website right now, they have a lot of updated products, so some of the files are out of date.

We do use 3 different LEDs, but there are multiple color bins to achieve a wider range of red/deep red.

I tried with and without UV a long time ago, and it didn't do anything, and that was trying it with multiple different nm. Specifically, it did seem to add a little extra resin on some plants, but hurt overall finishing time and yield. Too much spiky blue, violet or UV will stunt plants. And with LEDs, it doesn't take too many to have too big of a spike.

As for IR, that is 800nm +, my lights aren't toaster ovens. Maybe you were referring to "farred"? I did use 735nm up until about a month ago when I updated my spectrum this latest time, the new white LEDs have plenty of 700-750nm, it is very low amounts, but it does what it is supposed to do.

It doesn't stop at 660nm, one of the color bins I use is 660-670nm, and that is just its peak, it is a little wider, seems it drops off at about 675-680nm by looking a the chart. http://www.heliopto.com/files/Helixeon _Biochemistry_3W 2012_06 DS-21-10-05.pdf

My white LED starts at 420nm, and ends at beyond 750nm, it just has way bigger peaks in other color areas.

Height recommendations are on a light by light basis, they all require different heights. For example, my smallest light is 110w, and I recommend 14"-16", because that is where 600-800 Umol'/s is.

The biggest light I have is 590w at the plug, and it is 1883 Umol'/s at 12" below, it needs to be at least 24" away when operating at 100%, to not only have a proper footprint, but not have too much light concentrated below the light. The panel size is 25.5" x 25.5", so it doesn't have a problem covering 4x4.

Agreed that lots of LED can veg with fairly low PAR. My problem is most companies state specific footprints that we feel aren't honest in terms of delivering at the full footprint. This may be a slight error but I think it is intentional misleading marketing. Most people in this forum cannot touch and test all of the lights out there so we need a legitimate and quantifiable way to compare them. PAR is a good start but what do we do with those numbers. I agree plants can take the PAR and start bleaching at the numbers you said. But if we cannot all get to some common ground on what is acceptable and acceptable minimum, then how can consumers make an informed decision.

For example lets say a company claims a footprint of 4 x 4 and then someone independently measures the par at the edges of that footprint to be XXX PAR. At what low number can we all call BS?

To answer you Epistar question, I will send you advice up the ladder but I know we use primarily Epistar with a few to supplement from elsewhere since there is no one who makes everything we need at one company. We started over three years ago with 7 different nm LEDs and are up to 17 at this point to get the peaks/shoulders where we want them in our spectrum along with a few humps in the right places. We cover from UV to IR with only a few broad LEDs and the rest being specific wavelengths. That is about all I can give out as the rest would be proprietary. I am glad you like your heliopto LEDs but they would not give us what we feel is the optimal spectrum at this point. I personally spent a good portion of 6 months talking to different LED manufacturers before the Universal Series was launched. Finding quality powerful LEDs in the proper spectrum was by far the hardest thing we had to do. Most of the real development in LEDs is in the visible and human eye friendly ranges which are only a small part of our spectrum which makes finding what we want very difficult.

I did look at Heliopto and I cannot get their spec sheets to open/download. Are you able to get them open? Their links for the product sheets are either broken or in some cases html anchor links. From their product codes I cannot tell much about them.



So at Area51 it looks like you are using three different LEDs to produce your lights (6000k, 630nm, & 660nm) which is well reflected in the graph from your program. You seem to not offer UV and IR and you stop at 660. What do you think about UV/IR, also what about far red like 680? I have read some great research regarding 680 specifically for optimizing plant growth as well as UV and IR for cannabis.

Also, at what height do you recommend keeping your lights to obtain optimal results?

 

[stardustsailor]

I tried with and without UV a long time ago, and it didn't do anything, and that was trying it with multiple different nm. Specifically, it did seem to add a little extra resin on some plants, but hurt overall finishing time and yield. Too much spiky blue, violet or UV will stunt plants. And with LEDs, it doesn't take too many to have too big of a spike.

Well,you're right about that ...
At my current grow I'm using :

Two panels : 8 x CW , 12 x WW & 4 x Red 620-640 nm
Two panels :10 x CW ,2 x WW ,10 x red 620-640 nm & 2 x violet 390-410 nm
One panel of 6 x CW , 6 x NW ,8 x WW & 4 x red 620-640 nm
And three panels of 6 x CW ,2 x NW ,12 x WW & 4 x red 620-640 nm.....


All together 190 Watts at plug ,(drivers included ) ...
So ...
I use in total 192 leds at @350 mA :
60 x CW
12 x NW
72 x WW
44 x Red 620-640 nm
4 x Violet 390-410 nm ...

My two females (one "Indica dom " ,the other Sativa dom ,unknown strains ) for sure ,
have not the quantity of flowers I would like...
But they are full of resin glands !!! Even on some fan leaves .....
At both plants ....
Plants look light stressed from high energy light ... (Sativa dom :just a bit ,Indica dom :severely damaged )

Of course ...
I'm an idiot ...
60 x CW ? !!!!!
Even those four violets ( output :280-300mW approx. each ) ,probably contribute seriously in decreasing yield ,while increasing " quality "..
(Odour levels are way high...Lots of terpenes made ? If yes ,that is because of the high energy blue & violet light ... ) ..


For better yields I'm thinking into changing (next grow )
the total led numbers to :

20 x CW
20 x NW
96 x WW
52 x Red 620-640 nm
4 x Violet 390-410 nm ...

Lowering the BL light and spreading it more..
( CW= 455-465 blue ,NW = 440-455 Blue , with approx same phosphor blend ...
But I've to consider the small blue peak of WWs at 455-465..
96 pcs of WW add up and probably will provide enough BL at those wls...(455-465 nm )
Should lower more the number of CW and increase the numbers of NW ? ..
But then 440 BL from NW is more bioactive than the 455-465 nm one ,from CW and WW .
..$h!t ...That's tricky .... )
...And ...
Adding more ambers ,reds and FR ... ( WW & reds )
...
I'll keep the violets same ...Four of them per Sq.m ....
If still the yields are small ,then it might be that 4 of them ,per square meter ,are way much ...

 

[Beefbisquit]

Yeah, that is true, lots of exaggerated footprint claims going on, or inflated claims on how it compares to HPS...

I judge footprint on a couple things, not just the wattage of the panel. The most important thing is panel shape and size. The smaller your panel is, either it's the higher it needs to be to cover its intended footprint, or a lesser footprint. And the further away the lamp, the more efficiency you're losing. I try to stay within 4"-6" of the smaller panels perimeter, meaning if the panel is 11"x11", it would cover 20"x20"-23"x23", and for 110w, that is about right, giving 30-40w psf. The light doesn't have far to travel before hitting the plants, thus preserving its efficiency. That particular light still gets about 1020 Umol'/s at its center @ 12", so it still needs to be about 14"-16" to get optimal PAR.

Lights that will cover 4x4, what amounts of light that hits the edges of the 4x4, would be dependent of beam angle and intensity of the LEDs. Narrower the angle, the smaller the footprint, and lesser PAR at the edges. The wider the angle, at the edges, it will still be low, because anything beyond 90° disperses and spreads out too fast.

Here's the Heliopto page with all the data sheets http://www.heliopto.com/files/

They're updating their website right now, they have a lot of updated products, so some of the files are out of date.

We do use 3 different LEDs, but there are multiple color bins to achieve a wider range of red/deep red.

I tried with and without UV a long time ago, and it didn't do anything, and that was trying it with multiple different nm. Specifically, it did seem to add a little extra resin on some plants, but hurt overall finishing time and yield. Too much spiky blue, violet or UV will stunt plants. And with LEDs, it doesn't take too many to have too big of a spike.

As for IR, that is 800nm +, my lights aren't toaster ovens. Maybe you were referring to "farred"? I did use 735nm up until about a month ago when I updated my spectrum this latest time, the new white LEDs have plenty of 700-750nm, it is very low amounts, but it does what it is supposed to do.

It doesn't stop at 660nm, one of the color bins I use is 660-670nm, and that is just its peak, it is a little wider, seems it drops off at about 675-680nm by looking a the chart. http://www.heliopto.com/files/Helixeon%20_Biochemistry_3W%202012_06%20%20DS-21-10-05.pdf

My white LED starts at 420nm, and ends at beyond 750nm, it just has way bigger peaks in other color areas.

Height recommendations are on a light by light basis, they all require different heights. For example, my smallest light is 110w, and I recommend 14"-16", because that is where 600-800 Umol'/s is.

The biggest light I have is 590w at the plug, and it is 1883 Umol'/s at 12" below, it needs to be at least 24" away when operating at 100%, to not only have a proper footprint, but not have too much light concentrated below the light. The panel size is 25.5" x 25.5", so it doesn't have a problem covering 4x4.

God damn, I love the transparency of your company. It's so refreshing!

 

[Perro Negro]

Lights that will cover 4x4, what amounts of light that hits the edges of the 4x4, would be dependent of beam angle and intensity of the LEDs. Narrower the angle, the smaller the footprint, and lesser PAR at the edges. The wider the angle, at the edges, it will still be low, because anything beyond 90° disperses and spreads out too fast.

Why do you say "too fast"?

Maybe you were referring to "farred"?

I was asking about all three which is why I said UV/IR and far-red. Just curious since you don't refer to them at all on your site.

For better yields I'm thinking into changing (next grow )
the total led numbers to :


20 x CW
20 x NW
96 x WW
52 x Red 620-640 nm
4 x Violet 390-410 nm ...

Stardustsailor, that would be perfect and better violet % since it would be spot on with what we use. You would be right to back it off to this level. That is a sweet mix but I would recommend adding some far-red (around 720 nm) to significantly increase growth and yields. Some targeted 680 nm will also surprise you.

 

[stardustsailor]

That is a sweet mix but I would recommend adding some far-red (around 720 nm) to significantly increase growth and yields.

Can you explain a bit more ?

Some targeted 680 nm will also surprise you.

I'm not in fond of targeted leds ...Specially red ones ...
But I will try it with phosphors ...
Intematix has a nitride one with peak emission at 670 nm ,I think ...
I 'll put some in the " blend " to try it out ...

 

[Bumping Spheda]

Some in the blend? Do they sell single LED's with individual lenses? I thought you needed a "mixing chamber."

 

[stardustsailor]

Some in the blend? Do they sell single LED's with individual lenses? I thought you needed a "mixing chamber."

We 're experimenting into producing our own "remote phosphor " polymer screens ...
With various methods and various materials for substrates ...
Mixing chamber is the reflective and diffusive mirror or cup of either led or a remote phosphor luminaire..
Of course mixing chamber construction and characteristics are very crucial ....
You see ...
When a remote phosphor screen is lit by leds from one side ...It emits light from both sides ...("inner " & "outer " ,towards led & opposite side ..)
So this light from rem. phosphor screen , going back to leds / dies ,is needed to be reflected ( and diffused ) "outwards " again ......
That is the main role of a mixing chamber ....

 

[Bumping Spheda]

When a remote phosphor screen is lit by leds from one side ...It emits light from both sides ...("inner " & "outer " ,towards led & opposite side ..)
So this light from rem. phosphor screen , going back to leds / dies ,is needed to be reflected ( and diffused ) "outwards " again ......

Dang, that sounds rough. That's a pretty big blow to the efficiency increase we were hoping for, right?

Best of luck with your endeavors. Keep us posted, it all sounds really interesting.

 

[stardustsailor]

Look...
It's tricky ....
Not difficult to be made, just tricky ....

And has a lot of calculations (I do not like maths ! ) ...

...

Well ..
In the "phosphor & leds school " ( !!! ) of led growing ,there are some drawbacks ....

Main principle of that " school " is the use of various uv , violet & blue dies (led chips ) to excitate a phosphor layer ...

Say ordinary high power Phosphor white leds ....(not the RGB multichip ones )

-One drawback is the power losses that occur from phosphor layer and the "encapsulating " materials (soft silicones,usually ..) ,from absorption .

-Another drawback is the light that is emitted by the "phosphor" ,part of it returns to the led die ...
Die works both ways ..Making light from electricity ..Or making electricity from light ...
When doing both at same time ,efficiency(..of both actions ... ) drops ..

-Heat ...Longer Wavelength light from phosphor (more photons with less energy ,from the ones used for excitation ) ,going back to die ,rises Tj ...

-Heat ..from Die ..Destroys phosphor layer ,slowly....And efficiency drops during operation ..
And color shifts happen ...(towards blue ) through usage time (service life ).... Many bad things .....


Now...
Remote phosphors ....

The phosphor layer is far away (Ok ..Not that far away...Not kilometers or miles ...Few mm or cm ,only ) ,from the led die ....

-Heat does not alter the phosphor characteristics so drastically ...Prolonged life and stability of phosphor ....

-Light from phosphor that hits the chip ,turning it into a photovoltaic device is diminished greatly...
Most light from the "die side " of phosphor layer is reflected back( by ' mixing chamber ') to the illuminating side .....
Die efficiency increases ...

-Less heat generated at die ...Again ...Die efficiency increases ...

-The light ,that comes through the remote phosphor glass or polymer ,thin screen (1-2 mm thickness ) ,
is glare-free (no visible led sources underneath ) and of great -almost absolute -homogeneity ...(fully diffused )
....Like sunlight ,after passing through atmosphere,before falling on leaves (..Well...Kinda ...)

Tricky part A is mixing some phosphors ....
http://www.intematix.com/products/phosphors/led-phosphors

Consider phosphors as Green ,yellow ,orange and red leds ....

With remote phosphor method ,one can have
an array of 7x7 one watt chips (350mA )
One chip at 390-410
One at 430-440
One at 440-445
..445-450
..450-455
..455-460
&
..460-470 ..
Seven different dies of violet & blue light ...
Arranged in 7 rows or lines ...
( 50 Watt approx )

Place a heatsink on the array's back ...

Place a reflector (and diffusor at same time )

Place a phosphor doped plastic screen on top ...

Flip the switch ...

..
Now..." phosphor doped "....

Plenty of ways to do it ...
I.e .
Mix phosphor blend ( fine powders mixed together ) with " liquid glass " part A or
a fine grade extra transparent epoxy part A (or B ..) ....

Mix really well ...For long time ...
Place it maybe in Ultrasonic cleaner ....
Very good mixing is needed ...

Spray it over on a Plexiglass screen ....Or glass screen ...Or polycarbonate screen ...
(thin or thick layer of spray , depending on phosphor particle sizes ...And % of volume ,from each different phosphor in the "blend " / " mix " ...And of course depending on how much blue/violet is wanted to pass trough screen .....)

Clean the paint gun with acetone or something similar...

Now spray the screen again with part B (of "liquid glass " / liquid transparent epoxy ....(thinnest ,possible )

Let the bonding / curing to happen ...
Here you are ..
Your own remote phosphor screen ...

(Really simplified .... And just one of few different ways to make ... ) ..

Now the screen is your green ,yellow,amber,red and far red ....." leds " ...

Many maths here ..
Particle size of phosphor ,density ,volume(dimensions ) of screen ,
screen (substrate ) ang bonding (i.e. epoxy )material optical and chemical specs ,ect,ect....

But doable enough ,nevertheless....

What you get from this method firstly is "full " light ..From 390 up to 750 ...
Some light from dies (390-470 nm ) passes through screen (Another tricky part ...To adjust ..)
Most of light is at the range ,that the phosphor blend is made to emit...

Phosphor last for way longer and does not color shift ...

Led die Efficiency increases ...

Light is glare free and fully diffused...Almost absolute homogeneity...
....
And some more good ones....


I think that I like mostly that way ....
I'm bettin' on it ....



Say the remote phosphor " ASL 24 MK RP "panel ,has
4 x violet 390-410 nm ....
4 leds per panel aren't many at this case ..A lot of UV /viloet is blocked (absorbed or reflected back ),from PMMA -Polycarbonate-glass screen .... )
6 x 440-445 nm
4 x 445-450 nm
6 x 455-460 nm
4 x 465-475 nm

Starting from 390 nm up to 475 nm approx with a "pump-bump" at 440-460 nm ...

Overall % of power that passes through screen as light 390-475 nm is about 10-15% of total
flux....Maybe even ,a bit less (8-9% ) ....

The remaining 85-90 % of light power comes from remote phosphor excitation ...
( flouorescence ).....

Say we used one green ( i.e peak at 510 nm ),one yellow (580 nm ),one orange (600 nm )and four red (620-640-660-670 )phosphors at a certain analogy in between them ( volume-wise ) ...

Then applied the blend on a polycarbonate (transparent),say 0.8 mm thick, screen ...

Constructed (that is ,in fact,the most difficult part ) an efficient "mixing chamber "....
Highly reflective (>96% ) but also highly diffusive (>95% ) materials needed...
Can not just be mirror polished ally ....
It can be "hammered " pattern ally reflective sheet, though ...
Not the best material out there,but easy enough to obtain...
(....The absolute Best, would have been a plastic housing ,plated with those weird materials I/matix suggests ... )

...

.....Thinking of removing the plastic lenses of led units ..
Anyway mixing chamber enviroment is going to be totally isolated...
No need for protective lenses at leds ...
Can be just fine with their bare silicone domes exposed....
...
Testing is needed...
Maybe difference in efficiency is not going to be great ....
Or,maybe is...

...
Anyway...
A whole Brave New ...way for growing ,this one , regarding leds ....
I trust is going to kick ......ok...
...ya'all know what ...

 

[Farscaper]

What changes were made frpm the 2012 to the 2013 model? Also, The tent i use currently is lacking in headroom... would it be a better to use 2 of the A51-90's or 3 of the A51-60's? the tent is 2' x 4' and 5 feet tall.

Yeah, that is true, lots of exaggerated footprint claims going on, or inflated claims on how it compares to HPS...

I judge footprint on a couple things, not just the wattage of the panel. The most important thing is panel shape and size. The smaller your panel is, either it's the higher it needs to be to cover its intended footprint, or a lesser footprint. And the further away the lamp, the more efficiency you're losing. I try to stay within 4"-6" of the smaller panels perimeter, meaning if the panel is 11"x11", it would cover 20"x20"-23"x23", and for 110w, that is about right, giving 30-40w psf. The light doesn't have far to travel before hitting the plants, thus preserving its efficiency. That particular light still gets about 1020 Umol'/s at its center @ 12", so it still needs to be about 14"-16" to get optimal PAR.

Lights that will cover 4x4, what amounts of light that hits the edges of the 4x4, would be dependent of beam angle and intensity of the LEDs. Narrower the angle, the smaller the footprint, and lesser PAR at the edges. The wider the angle, at the edges, it will still be low, because anything beyond 90° disperses and spreads out too fast.

Here's the Heliopto page with all the data sheets http://www.heliopto.com/files/

They're updating their website right now, they have a lot of updated products, so some of the files are out of date.

We do use 3 different LEDs, but there are multiple color bins to achieve a wider range of red/deep red.

I tried with and without UV a long time ago, and it didn't do anything, and that was trying it with multiple different nm. Specifically, it did seem to add a little extra resin on some plants, but hurt overall finishing time and yield. Too much spiky blue, violet or UV will stunt plants. And with LEDs, it doesn't take too many to have too big of a spike.

As for IR, that is 800nm +, my lights aren't toaster ovens. Maybe you were referring to "farred"? I did use 735nm up until about a month ago when I updated my spectrum this latest time, the new white LEDs have plenty of 700-750nm, it is very low amounts, but it does what it is supposed to do.

It doesn't stop at 660nm, one of the color bins I use is 660-670nm, and that is just its peak, it is a little wider, seems it drops off at about 675-680nm by looking a the chart. http://www.heliopto.com/files/Helixeon _Biochemistry_3W 2012_06 DS-21-10-05.pdf

My white LED starts at 420nm, and ends at beyond 750nm, it just has way bigger peaks in other color areas.

Height recommendations are on a light by light basis, they all require different heights. For example, my smallest light is 110w, and I recommend 14"-16", because that is where 600-800 Umol'/s is.

The biggest light I have is 590w at the plug, and it is 1883 Umol'/s at 12" below, it needs to be at least 24" away when operating at 100%, to not only have a proper footprint, but not have too much light concentrated below the light. The panel size is 25.5" x 25.5", so it doesn't have a problem covering 4x4.

 

[Perro Negro]

Can you explain a bit more ?

I'm not in fond of targeted leds ...Specially red ones ...
But I will try it with phosphors ...
Intematix has a nitride one with peak emission at 670 nm ,I think ...
I 'll put some in the " blend " to try it out ...

I agree that targeted spectrums are hard to deal with individually or in small numbers but when we use 17 different LEDs (mostly targeted and a few broad) in large panels we are able to get a beautiful curve. The goal for us is to get as close to the the action spectrum as possible while incorporating cannabis specific knowledge. We feel this will ultimately allow us to create the best light possible. We do not worry ourselves with cost when designing the spectrum. We feel cutting costs negates the reason for making a light. After all this is a labor of love for all of us isn't it?

Some research has shown that 680 (675 to be exact but I have yet to find a 675 chip) plays a large role in the relative action of growth. Check out:
THE ACTION SPECTRUM, ABSORPTANCE AND QUANTUM YIELD OF PHOTOSYNTHESIS IN CROP PLANTS
K. J. McCREE

Good holiday reading, enjoy.

 

[FranJan]

Phew, you guys and your big brains . Think I pulled something reading all that .

Anyone seen these? Looks like side lighting for 1%ers, (+$100.00 for 10 watts).
Lumex SunBrite

Nice modular design, pretty tight 660. They should get in the 730nm business. Make them with built in timers.

 

[Campo Cultivator]

YEAH iVE BEEN LOOKING INTO THOSE it might do nicely between rows on a hydro set up as a supplement

 

[PetFlora]

Damn, I thought this was an LED Links thread. LOL

Not that I'm complaining. I opened it today to see whether astirgrows was listed, and BAM mega tech info

SDS, as per my idea presented earlier in the week over on your thread, would a bubble/dome screen be better than a flat one? I have a ~ 1/3 dome plastic cover on my kitchen light fixture, and have seen similar even on square and rectangular hallway lights

 

[FranJan]

YEAH iVE BEEN LOOKING INTO THOSE it might do nicely between rows on a hydro set up as a supplement

I do like the diodes, especially the reds which cover 655 to 665 and avoid the problems that most 660nms do by having too much spectrum in 670nm, which according to some delays flowering, and would probably explain one of the reasons SDS isn't the biggest fan of 660nm since cheaper diodes probably have to much 670nm. Lumex needs to price these things for people, not for commercial growers only! Or at least get some of these horti grade lights into someone's panels. Illumitex too!

 

[stardustsailor]

explain one of the reasons SDS isn't the biggest fan of 660nm since cheaper diodes probably have to much 670nm....


Yeap ! ...One of the reasons....



Now if 660 are combined with some 620-630 and/or some 640 ...
Then I've different opinion about 660 nm reds ...

I'm just not fond of red leds ,for plenty of reasons ...
But .....
The only way to get rid of them once and for all ,seems to be red nitride phosphors...(remote or not ..)

Otherwise ,they just have to be there ...
The wider the range from 600 to 660-670 nm,they will cover ,the better ..

Still ,what I consider as " primal basis" of the "mix-blend-config " ,is the Warm white led ...
The warmest ,the better ....(<3000 K )

 

[PetFlora]

explain one of the reasons SDS isn't the biggest fan of 660nm since cheaper diodes probably have to much 670nm....


Yeap ! ...One of the reasons....

Now if 660 are combined with some 620-360 and/or some 640 ...

I believe you accidentally transposed the range. Don't you mean 620 -630

 

[stardustsailor]

Nope ..
I mean 600- 670 ....

Plants take advantage almost with the same efficiency all wls from that range ...**
It would 've been pretty weird for plants to " focus" just in a narrow wl band ,in order to use it's photons to produce energy ...
Almost none from photo-receptors / pigments is "narrow peaked " ...
In all bands ( R-G-B ) of visible PAR ...

****
600 nm ===>670 nm:
-more photons
-higher absorption
-Quantum efficiency decrease

670 nm ===>600 nm:
-less photons
-lower absorption
-Quantum efficiency increase


So ..the wider the range of reds covered the better ...
At low overall fluxes (<300umol/sec ) ,red should be dominant at ~60%.Followed by green (yellow) and blue (30-35 % both.)
FR can be at 5-10% (great loss there ,though ) in order to control ( counteract ) with red ...

As overall fluxes increase (300-1500 umol ) ,red should drop to 45-50% ,green should increase at 30% ,blue at 10-15% ,rest should/could be FR & UV ...


Still experimenting ,still learning ....


For now :

The fuller the red band (meaning all wls at equal power ) ,the better the productivity ...
Narrow,high peaks ,should be avoided at red wls ...At any red wl ...
That is for red light quality -wise ....

The lower the overall flux ,the more red .( Even if reds are high ,still do not saturate PS ,due to low power ... )
Higher overall fluxes ,less red .(High light Power .more "slow 'n' easy " Ps is needed by lowering the reds .. Otherwise ...Burn,baby burn..)
That is for red light-quantity wise ...

 

[PetFlora]

^ Well said!

However, I am still confused by your statement...

'Now if 660 are combined with some 620-360 and/or some 640 .. '

Don't you mean 620 - 630 ...