CXA 3000°K 80 vs 93 CRI .An Estimation.

Greengenes707 said:

The lower output was always clear. But with the RQE factored in...the spectral efficiency gains seem to be near nothing.

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SupraSPL said:

Hopefully we can get more AB chips.

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SupraSPL said:

Awesome graphs thank you SDS! Honestly, the works from you and Mr Flux are changing the entire cannabis world, but the Cannabis world does not know it yet

So the high CRI has a steady slight advantage in the deep red range and the 80 CRI just pumps out so many more photons I am sold on that SPD. For those that don't know. this analysis is between the brand new top bins Cree added the CXA datasheet. We had access to some of the 80 CRI AB chips, but not yet the 93 CRI Y2 chips. Hopefully we can get more Z4 or AB chips.

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SupraSPL said:

So here are some of the contenders for the best standard-CRI COB grow lights potentially available:
CXA3070 2700K
CXA3070 3000K
CXA3590 2700K
CXA3590 3000K
Vero 29 3000K
Vero 29 4000K

I have been rating and recommending COBs based on the minimum flux numbers supplied by the manufacturer data. Mr Flux has pointed out that since the Crees are binned by efficiency and the Veros are not, that this approach gives an advantage to the Crees on paper, and I agree. This also helps keep the price down on the Veros. So are there poor performing Veros and awesome Veros all mixed in or do most meet the "typical" rating? Also, how far above the minimum does the typical Cree perform? Unfortunately we need a spectroradiometer to find out. Until then, I will have to rely on the minimum numbers for comparisons.

To make matters more complicated, the 3000K Vero curve is more like a 2700K Cree. A 4000K Vero is more like a 3000K Cree. Any chance we can uncomplicate some of that with your spreadsheets SDS?

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SupraSPL said:

Another big question regarding COBs, how much light should we be pumping into the typical canopy? Is the CXA3590 or Vero 29 too concentrated? Is the CXA3070 too concentrated at 1.4A or 1.9A? Even at .9A and 30W/sq ft I am noticing white tips on many of my ladies and I have never seen that before. It does not seem to compromise bud quality, but is it a signal that we are in the optimum light range? It is well known that increasing PPFD will increase yield, but the law of diminishing returns does apply.

Since we now have so much control of how many photons we want to put into the canopy, what size is the right size nugs? Greengenes pointed out that his favorite nugs tend to be a few down from the top. I agree completely. Sometimes top nugs have a bit of dreading or fresh pistils. Sometimes top nugs are so big that the inside is very shaded out and light green. God forbid, sometimes very large top nugs are more likely to have a touch of mold inside. So what I am suggesting is that there may be additional reasons to try and spread the light as much as possible and avoid the brute force approach of maximum photons from above. For some growers maybe that means use shelving and have two layers of canopy? For others it may mean use more side lighting, etc.

On the other hand I am an organic soil grower. Maybe the chem guys can put a lot more photons to work?

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The total amount of energy received at ground level from the sun at the zenith depends on the distance to the sun and thus on the time of year. It is about 3.3% higher than average in January and 3.3% lower in July (see below). If the extraterrestrial solar radiation is 1367 watts per square meter (the value when the earth-sun distance is 1 astronomical unit) then the direct sunlight at the earth's surface when the sun is at zenith is about 1050 W/m2, but the total amount (direct and indirect from the atmosphere) hitting the ground is around 1120 W/m2.[3] In terms of energy, sunlight at the earth's surface is around 52 or 55 percent infrared (above 700 nm), 43 or 42 percent visible (400 to 700 nm), and 5 or 3 percent ultraviolet (below 400 nm).[4] [5] At the top of the atmosphere sunlight is about 30% more intense, having about 8% ultraviolet (UV),[6] with most of the extra UV consisting of biologically-damaging shortwave ultraviolet.[7]

Direct sunlight has a luminous efficacy of about 93 lumens per watt of radiant flux, higher than most artificial lighting, including fluorescent. Multiplying the figure of 1050 watts per square metre by 93 lumens per watt indicates that bright sunlight provides an illuminance of approximately 98 000 lux (lumens per square meter) on a perpendicular surface at sea level. The illumination of a horizontal surface will be considerably less than this if the sun is not very high in the sky. Averaged over a day, the highest amount of sunlight on a horizontal surface occurs in January at the South Pole (see Insolation.)

Sunlight is a key factor in photosynthesis, the process used by plants and other autotrophic organisms to convert light energy, normally from the sun, into chemical energy that can be used to fuel the organisms' activities.

https://en.wikipedia.org/wiki/Sunlight

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