I generally do not have anything to do with CoBs. LEDs are too heat sensitive to cram a bunch of them into a small area.
There is one I saw and found its Spectral Power Distribution Characteristics to be exceedingly of interest. That is the Luxeon Fresh Focus Red Meat.
When looking at White LEDs the first thing I look at is the spectral distribution. What I specifically look for is the wavelength of the peak to be in the Deep Red (650nm) region. And for the blue peak not to be too high.
In this case I chose Red Meat over Marbled Meat because of Marbled's Green peak at 530 nm.
The problem I saw in the post of this thread is the use of LUMENS. Lumens has NO place in a discussion regarding Grow Lighting.
I purchased two the these CoBs, and measured the PPFD (image number 2). This image was created from a data dump from a StellarNet BLUE-Wave spectrometer with an app I created to convert the data to an SVG image.
This LED has substantial Deep Red and well into the Far Red (710 nm) region.
Just for you guys that like to use Lumens I dumped the exact same data in Lumens. Notice how it does not even remotely resemble the actual PPFD characteristics of this LED. Lumens is about eyballs, not plants.
If I were to look at this CoB in terms of Lumens, it would have no deep or far red.
Lumen measurements takes the watt measurement and multiplies it by the CIE Photopic Luminous Efficacy factor. Totally irrelevant to grow lighting.
Where I saw trouble in this thread was in trying to pick a CoB based on the Lumens per Watt efficacy.
Lumens per Watt is a ballpark number that can be used to estimate the Efficacy of a series of White LEDs.
All the LEDs in a series such as the Vero 29 are made with the same Deep Blue LED. The efficacy of every LED in the series is the same. The output flux difference from one CCT or CRI to another is the phosphor wavelength converter efficiency.
If you base decisions on Lumen/Watt efficiency you will likely end up with an LED with less photosynthetic efficiency.
Most times in a series of White LEDs, the 2700 or 3000K with a CRI 90 is the LED with the best PPF.
Unfortunately the Vero 29 datasheet did not include the spectral distribution for their CRI 90. That eliminates it from my list of viable CoBs.
Even if the Vero 29 had an ideal spectral distribution I still would not use it based on its thermal characteristics. The number one characteristic when evaluating a LED should be the Thermal Resistance from junction to case. The datasheet does not specify the thermal resistance but it does show a 45° C delta between junction and case. This means no matter how substantial your thermal management, the junction will be 45° warmer than the case.
Also the datasheet specifies TYPICAL, there is nothing typical about an LED. You must look at the characteristics at the current and temperature it is going to be used at.
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