540w of TastyLED, 4x4 tent, 8 plants = 1 pound yield

Rahz said:

As I said, I don't take measurements to determine the PPF. 3500K CD at 2.1 amps provides 75 watts and 50% efficiency (2.3 umol/j) 75 x 2.3 = 172.5 PPF. I was just kidding about it being my motto. I had just realized the price and PPF were the same and thought it was amusing, but yes if one emitter provides 172.5 PPF then 4 will provide 690 PPF. I'm not sure why you think the total PPF would be irrelevant as it represents the total photon output of the lamp.

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Is that how the chart on the site works too?
I did not see anywhere a hight to determine the PPF or PPFD in said areas? Was this determined through calculating the emitters output? I'm trying to figure out the output at different heights. Trying to understand.

The height does not determine the PPF. The PPF is the amount of photons the lamp produces.

The PPFD will decline with height when more light is being radiated onto the walls rather than the plants. The lowering of PPFD will be based on the percentage of light contacting the walls and the reflectivity of the walls.

The optimal height of an emitter will generally be 50% of the width they are intended to be used over with 90 degree optics but I find raising them a bit more can provide a more even spread. The width an emitter should shine on is determined by the output and desired intensity. The 2100 series is going to be comfortable running 12-14" above the canopy

Rahz said:

The height does not determine the PPF. The PPF is the amount of photons the lamp produces.

The PPFD will decline with height when more light is being radiated onto the walls rather than the plants. The lowering of PPFD will be based on the percentage of light contacting the walls and the reflectivity of the walls.

The optimal height of an emitter will generally be 50% of the width they are intended to be used over with 90 degree optics but I find raising them a bit more can provide a more even spread. The width an emitter should shine on is determined by the output and desired intensity. The 2100 series is going to be comfortable running 12-14" above the canopy

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So basically you're telling me I cannot get a par meter reading? Earlier on I didn't mean that total. PPF was irrelevant. I meant adding up & calculating these #'s doesn't actually give the real-life performance status of any said fixture. Maybe it does when there's no lens or reflector pertaining to a COB chip itself. But your not selling chips here, your selling light fixtures. I've been considering 1-a few of your lights for side-lighting to replace my T-5's, this is why I'm inquiring. I am planning on using Amare's above but their lights need certain distances for the spectrum to mix properly & the monos have 90• lenses so removing the glass on the COB lenses is not really helping in a side-light, close quarter grow style.
After reading your web-page I began to realize that these lights are not necessarily designed for max-performance but for the most efficient. Like the sweet-spot between yield & electrical efficiency. Am I correct?
So, are you able to provide me w/ any #'s from an actual par-meter?

The reflectors absorb about 2% of the total light output. The drivers output 100-108% of the stated current so I feel the PPFD values are fair estimates. That information is useful/relevant along with the PPF, lumen count and par wattage. All of that should be useful for planning. Some lamp makers don't provide any of that.

That being said I will eventually be playing around with par readings under various single emitters and will share my findings here on the forum.

Hybridway said:

After reading your web-page I began to realize that these lights are not necessarily designed for max-performance but for the most efficient. Like the sweet-spot between yield & electrical efficiency. Am I correct?

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The performance level as a measure of yield per square foot is a function of PPFD, par watts per foot, lumens per foot.
The price per par watt in the 2100 series is very competitive while still having better efficiency than most lamps.

Rahz said:

The reflectors absorb about 2% of the total light output. The drivers output 100-108% of the stated current so I feel the PPFD values are fair estimates. That information is useful/relevant along with the PPF, lumen count and par wattage. All of that should be useful for planning. Some lamp makers don't provide any of that.

That being said I will eventually be playing around with par readings under various single emitters and will share my findings here on the forum.



The performance level as a measure of yield per square foot is a function of PPFD, par watts per foot, lumens per foot.
The price per par watt in the 2100 series is very competitive while still having better efficiency than most lamps.

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I see what you mean. It just makes it hard for consumers to compare fixtures when making a purchase & to plan their room layout based on what they'd like to achieve at a certain height. And hight determines sq' covered. So to me that would be important. Thank you for answering my questions. Take care.

No problem, thanks for the input. I will put some consideration into doing par maps of some sort. Since I will be phasing out the lower current lamps I've changed the main page to suggested footprints, which another posted had suggested was needed.