Can someone explain 80 CRI vs 90 CRI- LED

NoFucks2Give

NoFucks2Give

Well-Known Member
Greengenes707 said:
That wheel has already been invented
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Thanks for posting the photo of @wietefras fixture. He did a very good job. Those brass fitting are a bit pricey.

I've been running thermal experiments for months now, and found that thinner copper plates to mount the CoBs is better (less thermal resistance), clamping them to the pipe works better than solder, and the copper plate should be a minimum of 4" long along the pipe. I would do a 48" long 0.062" thick bar clamping it to the pipe on each side of the CoB and mount a CoB every 4". When my new milling machine arrives, I will make a custom plate to mount the CoB on the bar and the bar to the pipe with the same bracket.

With the bar clamped to the pipe with C-Clamps, in the pictured test setup, and running 11° C water through the pipe, the thermal pad temperate was 23° C and ambient room temp was 27° C.
With water at 27° C the thermal pad temp was 42° C.

The reason I am working on this is because I want to use Deep Red LEDs and they are extremely sensitive to heat. I estimate most fixtures with red LEDs lose about 50% of their radiant flux to heat.
 
wietefras

wietefras

Well-Known Member
@NoFucks2Give Intensity isn't the same everywhere in that triangle. There is also light coming from the led/COB outside of the beam angle. Beam angle only means "all angles over 50% of max light intensity"

NoFucks2Give said:
So you are saying a 3000K 70 CRI has higher PAR value than a 2700K 90CRI?
If so, that is incorrect.
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Citizen themselves posted PPF values for a lot of versions of their 1825 and 3618 COBs.

From that sheet:
3000K 70CRI 243umol/s
2700K 90CRI 229umol/s
 
wietefras

wietefras

Well-Known Member
NoFucks2Give said:
Thanks for posting the photo of @wietefras fixture. He did a very good job. Those brass fitting are a bit pricey.
Click to expand...
That's why I also wanted to try an S-shaped bent fixture from one single pipe (or use soldered fittings).

I wouldn't go with cheap plastic fittings though. If it starts leaking you'll quickly regret saving a few bucks
 
Rahz

Rahz

Well-Known Member
Greengenes707 said:
You have it backwards. Orange(590-620) is most effective(Relative 100%) at photosynthesis according to McCree. The whole range has 99-100 RQE. As where RQE falls slightly in the mid red region(630-645) and more so into deeper red(645-700)...but is where the photomorphogenic is said to make up for the slight decrease in carbon fixation. That photomorphogenic is only important to us if it's in dried flower weight and is quantifiable. But that is not what I saw in your experiment.
Your experiment results followed no pattern. They were random at best. There is no explanation other than a test that parameter got out of control in addition to a small sample to begin with(which even you acknowledge). Speaking of sample sizes...brings up the other experiment going on, the dawgs. Also too small to make any judgments other than, "they grew great pot". All great grows...but the conclusions being drawn from them are not accurate. I did the spectral side by sides(3v4, 3v3.5, 4v3.5) and the yields were negligible and not devoted enough to call a difference. Structure was notably different, but total yield was the same. Grows with larger plants and numbers. All documented in GG's garden thread that is now shut down.

@dro-man80 Has a nice experiment run going on. Good numbers and canopy size.
https://www.rollitup.org/t/one-more-run-with-the-cxbs-3000k-80-90-cri-qbs-are-next-in-line.938932/



That wheel has already been invented and turning for a while by @wietefras ...

You'll do fine with it.
View attachment 3944138

Quote from builder below VVVVV
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You're right of course. I tend to think of it in terms of +600 and -600. That does explain why YPF doesn't give a huge bonus to high CRI... though 90 CRI does benefit more from Mcree's data than the others.

Despite the grow parameters being off neither of the high CRI samples were shaded. I've been careful to not read too much into my experiment, or to assume Mcree is relevant in flowering and always point that out. But it's logical that ultimately some pattern should develop that favours a particular SPD.

One benefit of high CRI that seems to be showing up consistently is reduced flowering times. Did you observe that in your tests?
 
NoFucks2Give

NoFucks2Give

Well-Known Member
wietefras said:
3000K 70CRI 243umol/s
2700K 90CRI 229umol/s
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Thanks for the data, I do believe the graphs of the spectral distribution are each scaled differently and that gives a skewed view for comparing one CCT to another.
I have a 3000K on order to run my own test.


wietefras said:
S-shaped bent fixture
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I agree with the bent pipe. I watched some pipe bending videos on YouTube so I know what bender to use.


wietefras said:
wouldn't go with cheap plastic fittings
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The pressure is not that high, I did not solder my pipes and they hardly leaked, I used silicon sealant on the few of the fittings that did leak.
The PVC fittings work as reliably as the iron, copper, or brass. I used to do plumbing back in 1973. I could not believe a galvanized 3/4" Tee now cost $3.50. But then I also miss the nickel candy bars in 1960.
 
wietefras

wietefras

Well-Known Member
NoFucks2Give said:
I do believe the graphs of the spectral distribution are each scaled differently and that gives a skewed view for comparing one CCT to another.
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Technically they are scaled the same way. 100% on those relative SPD charts is where the maximum flux is for that model and all values in between are calcultaed as a percentage off that maximum.

You can sometimes also find spectral distribution charts with flux numbers instead of the relative numbers.

On the other hand, relative distribution charts can be also used to calculate lumen to PPF conversion rates. Which makes comparison a lot easier. Assuming the charts are correct.
 
NoFucks2Give

NoFucks2Give

Well-Known Member
nfhiggs said:
but green is not useless. That is a common myth
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You are correct, green is not useless. The thing is there needs to be more research on the colors between blue and red.

I attached a copy of the "Green paper" referred to in the Reddit link.

Very misleading title:

Green Light Drives Leaf Photosynthesis More Efficiently than Red Light in Strong White Light:
Revisiting the Enigmatic Question of Why Leaves are Green

It is a paper written based on a few cherry picked studies.
It has very little to do with photosynthesis, it's about absorptance.
What it fails to do is state any relevance to growing plants.
And no pictures. I like pictures.
It raises a hypothesis on how absorptance may be relevant to photosynthesis.

On the other hand

This recently published paper gives a very detailed look at Green and Yellow.
Light Quality Dependent Changes in Morphology, Antioxidant Capacity, and Volatile Production in Sweet Basil
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5007804/

BRG did better than BR
BRY did the best, better than the Sun. GH is GreenHouse

Regarding the volatile compounds below, which are a combination of data from two studies.

Only Blue did the worst. The Sun was second worst. Red was slightly better than the Sun.

The point to this post is the volatile compounds of BR compared to BRG.
Notice, in the image at the bottom of this post, the number compounds affected BR and BRG are about the same, but completely different compounds.

Bottom Line: Green is unpredictable from one plant spices to another.

MY OPINION: The results for BRY were a big surprise. I think there is some wavelength(s) between Red and Blue that need to be added to BR. I don't think it's green, but now Yellow is a possible candidate. Until the researchers figure that out, white is a necessity. Until then I'm working on a Red White and Blue fixture.

This one picture says so much more than the "Green Paper"
colorRecipeBasil.jpg

colorRecipeBasilVolatiles.jpg
 

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NoFucks2Give

NoFucks2Give

Well-Known Member
I superimposed 80 CRI over 90 CRI @ 3000K and 2700K and tried to remove the other CRIs best I could.
For what it's worth, I tried.


1212-80-90cri.jpg




If anyone else wants to try and do a better job, the two images are here and this is the SVG source:


<?xml version="1.0" encoding="UTF-8" standalone="no"?><svg xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:svg="http://www.w3.org/2000/svg" xmlns="http://www.w3.org/2000/svg">
<image transform="scale(.965,.925)" xlink:href="C:\1web\glr\photosynthesis\1212-90cri.jpg" x="0" y="0" height="655px" width="1003px" opacity="1"/>
<image xlink:href="C:\1web\glr\photosynthesis\1212-80CRI.png" x="0" y="65" height="507px" width="939px" opacity=".4"/>
</svg>

 

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Fauxton

Fauxton

Active Member
Just because I haven't seen it mentioned in this thread: the more red produced by a phosphor, the hotter the LED phosphor gets, the lower the efficiency. (Google Stokes Shift.)

I'm not against high CRI at all, just wanting to explain (in part) why high CRI is less efficient.
 
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Photon Flinger

Well-Known Member
Found out something that might be of use from my current 3000k 80vs90 CRI Vero 29c run.

2 plants going from veg under each took a week to adjust and the 80 CRI wasn't as healthy as the 90 CRI. Both were set to around 1800umoles at the canopy and temps steady at 25-28c lights on, going to 20c lights off with a 35-45% rh. 90 CRI now has the jump on the 80 CRI like others have shown.

It could be that the higher CRI is closer to natural light and requires less work for the plant to adjust. That would also explain the faster finish times since the plant doesn't have to recover as much.
 
NoFucks2Give

NoFucks2Give

Well-Known Member
Fauxton said:
I'm not against high CRI at all, just wanting to explain (in part) why high CRI is less efficient.
Click to expand...
You make a good and interesting point. What is the alternative? Thinking out loud here. Inefficient 500-550nm vs. 530+ red.

No contest. 650+nm or nothing. Anything else is why bother. The difference between the two is night and day.

Keeping in mind I use water cooling with 100% copper from the thermal pad to to the copper water pipe with near zero thermal resistance.

Also keeping in mind I'm an electrical engineer that knows how to design PCBs, and has a pick and place robot to populate the PCBs.

If I did not know how to design PCBs, CoBs would be the only option left.

If I were doing CoBs, either Luxeon Red Meat or Vero 1750-97.

When I ask someone why they pick a 3000K or 3500K they say for veg and flowering. Veg / Flowering is bullshit. If I'm a plant I want lots of Deep Red and a little bit of Deep Blue and I am very happy. Give me that green shit I'm going to suffocate. When I want a buzz, give me more of that Deep Blue with the extra energy. It 's like doin' a line of coke or if you're stingy, a Red Bull. Or let's compromise on an Adderall. Please don't give me that Veg blue, that shit's like crack.
 
NoFucks2Give

NoFucks2Give

Well-Known Member
Photon Flinger said:
higher CRI is closer to natural light
Click to expand...
Yes and no. Higher CRI means more red. Plants don''t give a shit about natural light, sunlight, or anything other than Deep Red and Deep Blue. Anything in between is suffocating. If you want to stress the poor little fucker, don't give her water 'til her leaves are drooping. She's a masochist and that shit makes her so fuckin' wet.
 
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NoFucks2Give

NoFucks2Give

Well-Known Member
Photon Flinger said:
1800umoles
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This is cool as shit. That CoB snob cyber bully cocksucker I mentioned, he was ranting about me using µMole instead of µmol/m²/s.

I'm like WTF else would it mean? The cocksucker just wanted to bust my balls. I smh and smile. I mean really? You think that petty bullshit is going to bother me after the shit I've been through?
 
P

Photon Flinger

Well-Known Member
NoFucks2Give said:
This is cool as shit. That CoB snob cyber bully cocksucker I mentioned, he was ranting about me using µMole instead of µmol/m²/s.

I'm like WTF else would it mean? The cocksucker just wanted to bust my balls. I smh and smile. I mean really? You think that petty bullshit is going to bother me after the shit I've been through?
Click to expand...

Who? That vendor guy with the youtube channel that acts like he knows something about light? Pacific something or other?

At least chinese manufacturers are nice when they try to blow smoke up your arse; that guy is just flat out nasty. Any first year bio student can run circles around him.

And yeah I just lazily type umoles. Or umols. Too lazy to use ansi char set to make it look pretty. Smart people can usually figure it out. PPFD not PPF, I know the difference as well and know that PPFD is all that matters.

As for higher CRI being closer to natural light, I think that is what CRI is by definition attempting to represent. The fact it has more red in it is a good point and might be the reason or an additional contributor.

Simple photosynthesis with PSI and PSII says that the photons are conditioned for 680 and 700nm anyhow so the more we give of those, the less work the plant has to do.
 
NoFucks2Give

NoFucks2Give

Well-Known Member
Photon Flinger said:
, I think that is what CRI is by definition
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That is correct. Most white LEDs are deficient in Red. I like people that know stuff. So many on this site do not.

Texas Instruments has a LED driver chip with an efficient high current driver for white and a low power driver for red. The chip is marketed to increase CRI. And I am always looking for new products withe high red output. So far only the Vero Decor 1750K 97CRI and the Luxeon Fresh Focus Red Meat are the only "white" LEDs I have found that I would even attempt using for growing.
 
Moflow

Moflow

Well-Known Member
Who? That vendor guy with the youtube channel that acts like he knows something about light? Pacific something or other?

Perhaps you can be more spacific.......?
 
P

Photon Flinger

Well-Known Member
NoFucks2Give said:
That is correct. Most white LEDs are deficient in Red. I like people that know stuff. So many on this site do not.

Texas Instruments has a LED driver chip with an efficient high current driver for white and a low power driver for red. The chip is marketed to increase CRI. And I am always looking for new products withe high red output. So far only the Vero Decor 1750K 97CRI and the Luxeon Fresh Focus Red Meat are the only "white" LEDs I have found that I would even attempt using for growing.
Click to expand...

Agreed. Cutting through the jokers, especially the vendors, who don't know any better is par for the course on the Internet these days.

I am going to try the 1750k Decors in a run or two once I finish off my 3000k 80/90 CRI run. Been all over the place with different SPDs and find that these 3000k are great for the plants and easy on the eyes.
 
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