Looking for Opinions on Bridgelux EB3 90cri Strip Options

[ganjah]

I'm looking at building a new flower light for my 4x4 tent and I was hoping to get some input on my options.

Caveats:

I don't want to mix spectrum - I want to use a single strip color temp across the whole light fixture. If I want to add spectrum later, I'll do it in small amounts.

I lean towards the 90cri EB3 strips because they have a bit more far red (700nm-750nm) compared to the 80cri.

Graphs:

Original EB3 90cri graph for reference.

Edited EB3 90cri graph to show output advantages of 4000k vs. 3500k vs. 2700k.

Questions:

• 4000k or 2700k? These are the two I can buy right now in 90cri. Based on my poorly edited graph above, which 90cri spectrum would you prefer for flowering and why? I'm leaning towards 4000k because it has so much more near UV, blue, green, and red. It has almost as much deep red (600nm - 650nm) and more 660nm - 750nm.

• How many of each to cover a 4x4, and on what Meanwell HLG driver? The 4000k 90cri I can get are 2ft and the 2700k 90cri are 4ft.

[TEKNIK]

If you are using it for flowering then the 2700K cri90 is best

More blue in the spectrum tends to decrease yield, this does change for different strains but most of the time more red is better.

Although the blue keeps plants more compact and decreases yield it isn't all that bad in CRI90 and you can run it full cycle.

[TEKNIK]

Color temprature and CRI needs to be used as a guide for plant spectrums, it isnt the best way to judge a spectrum for plant growth but it gives us a good idea of how a spectrum will act.

You can completely change a spectrum without changing the color and CRI by using closer to UVA color or closer to far red colors.

[TEKNIK]

Just to give you an idea of what I'm rambling about.

I'm using the Highlights as an example
Look at the color temprature and also the CRI. All of these spectrums are completely different and will have very different effects on plant growth. But CRI and color temprature remain about the same

What you need to be looking at is the ratios of all the colors which not many horticultural companies provide

[Li_Mu_Bai]

4000k or 2700k? These are the two I can buy right now in 90cri.

Can you tell me where these are available. I've been interested in these Gen 3 90 CRI and have found no one that sells them outside of a special quantity order.

The graph on these shows a significant increase in spectrum but at a significant cost in efficiency. Is that not a concern for you?

[ganjah]

Thanks for the quick replies from both of @TEKNIK and @Li_Mu_Bai . I'm poor so I'm looking for the best bang for my buck.

Here's my cost/benefit calculus in order of importance to me

1. The most photons produced
2. In generally the most effective spectrum
3. For the lowest cost
4. Using the fewest watts at the wall
5. With the most uniform canopy spread
6. And the lowest build complexity
7. From the smallest bill of materials.

That's why I am looking at the eb3 90cri strips mounted to an angle aluminum frame. They seem to have quite a bit more far red output than the 80cri strips. I've found them at futureelectronics.com for US delivery.

What you say makes sense, @TEKNIK. Do you mind going into detail about why you recommend the 2700k? Is it because all that extra output in the UV/blue/green/yellow from the 4000k is bad for flower growth and development? I'm guessing here cuz I don't know, but I'll defer to your experience and wisdom. I ask because it conflicts with some recent anecdotal info I'm reading about near-UV being able to push higher cannabinoid counts.

When I look at the graphs of the 90cri eb3 strips, I see the areas under the curve. If that's an accurate depiction of the ratios of each wavelength to each other, I see almost no difference in red output overall or by relative intensity, but quite a big difference in the 400nm-600nm range.

If they don't provide ratios of some ranges to each other, is there a better way for me to judge the spectrums than looking at the area of the curve in these graphs to compare ratios of each wavelength to each other?

[TEKNIK]

I have tested the CRI90 2700K gen3
They dont have UV, none of the bridgelux gen3 have UV
They do have a very nice phosphor with plenty of red and far red
They are also pretty efficient for the price.
Heavy red spectrums are better for yields, the bridgelux 2700K cri90 is a very heavy red spectrum with a good blue to red ratio also.
More tests are need for an absolute conclusive result regarding near UV producing more cannabinoids but so far its looking pretty good and from what I have seen the plants seem to like a bit of near UVA, they dont need alot of near UVA to make a difference either.
All strains react differently to different spectrums so take what I say as advice to what works best in general.

Efficiency changes quite quickly with drive current
The more strips you have the more efficient the light will be at the board level.
Getting your driver loaded correctly also helps with efficiency and thats something most people dont discuss.

[Li_Mu_Bai]

I don't have much knowledge on the subject, but I've been studying my ass off for the past several days. I've been reading some good university level studies, some I'm barely comprehending. there are many variables at play in these studies, and at the end of the day the jury is still out, but there are some interesting findings.

This study was particularly interesting, as it was specific to cannabis: https://www.karger.com/Article/Fulltext/489030

It compared old school 1000w hps and two different LEDs. One of the leds (NS1) had a unusual light specrum, a lot of blue and a lot in mid range with some red and a little far red. The other led (AP673L)had a decent amount of blue (about the amount in a 3500k) and a lot of red and far red, relatively speaking. The HPS is just strong in the 550-630nm range, and little of anything else, virtually no blue.

The HPS had high plant stretch and growth, and highest yeild of plant material. But the interesting finding is that NS1 had the most THC, CBD, and THCV (which is particularly interesting to me). The other LED (AP673L) was a very close second.

Much more research is needed. But a cursory take-away for me is that a fuller spectrum has implications beyond just plant growth and dry material yield. I've been hearing for a long time from LED users (on the forums) that although yeild is about the same, or maybe even a little less, the quality, in terms of Terpenes, and density and trichome coverage is better. This would have to be attributed to a fully spectrum, which includes a lot more in the lower range.

Personally I'm thinking about switching to the 4000k CRI 90. Or having a mix.

[ganjah]

I've been growing under LEDs for five+ years. They grow great plants. Looking to upgrade now, tho.

@Li_Mu_Bai I've read the same about blue/near-UV, but I've also read Bruce Bugbee's latest research that indicate 5% in the near-UV area is the most you want to go for best flowering, and that UV beyond that is pretty inconsequential in his robust lab testing. I have no dog in the fight, I just want the best bang for my buck.

@TEKNIK thanks for the good details. Do you have a test report for the 2700k EB3 90cri you evaluated, so I can compare and see the wavelength distribution? You've just about sold me on them.

I'm leaning towards 20 of the 4ft 2700k eb3 strips in a 4x4, split between two fixtures of 10 strips each wire in parallel on a HLG-320H-42a because I want to dim them down as necessary ($65/ea at mouser right now). Does that seem like an efficient use of the strips??

Maybe a -36a would be better? There's no -36ab or -42ab in stock anywhere. Or is that too much ppf and 240h-36a or 240h-42a would be the best? I don't mind running the strips low - I have to buy 20 of them either way.

[TEKNIK]

I will share the test reports in the next day or 2

3-5% of near UVA is all thats needed as far as I can tell to increase THC content
Tests are being done as soon as they can be but it takes a long time and more than one test needs to be done for conclusive results.

I personally don't trust Bruce Bugbee and just see him as a salesman for his PAR meters which arnt very good.
He pretends to have found something new and special but all in the videos I have seen he isnt stating anything new and just talking about common knowledge that has been around for over 10 years.
The reason I think he is doing this is because his original PAR meter didn't read outside of 400-700nm and now he wants to sell his new PAR meter that has a much broader range. Its actually too broad and can give very confusing readings if you dont have a spectrometer reading to match the PAR reading.
But if you have a spectrometer you dont need the PAR meter.
I dont mean to shit on anything he is doing its just how I interpret his messy educational videos.

20 of the 4ft strips would be a pretty good build, I hope you can find the driver you need. It will hit about 2.85 micromouls per joule at board level with the 2700K cri90, as you will be running a 4ft at about 500mA. You wont need heatsinks either although its best to run some flat aluminium angle to keep things rigid so you dont break them, angle is best. Your light would be very efficient and better in my opinion than a fluence for efficiency and growth.