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Lighting

TorturedSoul

Member of the Month: May 2009, Oct 2010, Sept 2017
Hi. Depends what you want to do and how large is your growing room. If you gave space then ofcourse you can do 2x300w more plants and 300W Led can do the same as 600 HPS in nowadays.

Do you work at LTL?
 

fishmeyer

New Member
I am setting up a vegetative grow room and always used flourescents for vegetating but heard its better to go with leds with a full spectrum-something with all the colors needed for tight node growth or best to go with a more blueish led??? So confusing nowadays with all the different spectrums
 

fishmeyer

New Member
So go with all blue spectrum?? Was thinking of adding a 2700 light for a little bit of red growth- I know a plant uses mainly red and blue but I also heard that using red causes more internodal growth - is that true??
 

LedTestLab

New Member
Some long long time ago when nobody even wasn't thinking about leds some old grow man told me that if you can do mh and hps together its the best way for plant. Im not biological man, Im just working in LTL. And do some tests for cobs. Mixed 3500K ( red sun) with 6500K ( blue day light)
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TorturedSoul

Member of the Month: May 2009, Oct 2010, Sept 2017
So 1) diagram is from 3 COBS together 2 x 3500K and 1 x 6500K
2) diagram is from 2 COBS with 3500K
3) diagram is with 70w cob with 6500K

That's nice, but lumen and luminous flux don't really have any correlation to a light's prowess at growing plants. How about the PPFD (Photosynthetic Photon Flux Density), expressed in µmol per m² per second, preferably over a given area - measured at various points, in a grid pattern - at a given height? That would be useful.
 

LedTestLab

New Member
PPFD we can calculate if we know all led parameters ( lux, lumens, wattage) and of course the distance from light to plant. To calculate PPFD we need to take every wavelengths from 400nm to 700 nm...

There you got some calculations from 3 different wavelenghts:


I can determine the wavelength for each spectrum. For example: 550 nm - intensity 37268 (lumen), Beam width: 120 degrees, Height: 65 cm, Length: 1.22m (4ft) x 1.22 (4ft)
Hours per day (photoperiod): 18 h
Area Illuminated by light at a given distance: 1.3273 m ^ 2

Total Light output:
Radiant Flux: 55.171 W

PPF 152.19 μmol / s
PAR Watts: 33.102 W
Lumens: 37268

Intensity at distance:

Radiant Flux Density: 41.565 W / m ^ 2
PPFD: 114.66 μmoles / sec * m ^ 2
About Irradiance: 24.939 W / m ^ 2
Lux: 28078
Daily Light Integral (DLI): 7.4301 mol / day




450 nm - intensity 37268 (lumen), Beam width: 120 degrees, Height: 65 cm, Length: 1.22m (4ft) x 1.22 (4ft)
Hours per day (photoperiod): 18 h
Area Illuminated by light at a given distance: 1.3273 m ^ 2

Total Light output:
Radiant Flux: 843.05 W

PPF 1649.1 μmol / s
PAR Watts: 438.38 W
Lumens: 37268

Intensity at distance:

Radiant Flux Density: 635.15 W / m ^ 2
PPFD: 1242.4 μmoles / sec * m ^ 2
PAR Irradiance: 330.28 W / m ^ 2
Lux: 28078
Daily Light Integral (DLI): 80.508 mol / day




650nm - intensity 37268 (lumen), Beam width: 120 degrees, Height: 65 cm, Length: 1.22m (4ft) x 1.22 (4ft)
Hours per day (photoperiod): 18 h
Area Illuminated by light at a given distance: 1.3273 m ^ 2

Total Light output:
Radiant Flux: 457.33 W

PPF 2335.8 μmol / s
PAR Watts: 429.89 W
Lumens: 37268

Intensity at distance:

Radiant Flux Density: 344.55 W / m ^ 2
PPFD: 1759.8 μmoles / sec * m ^ 2
PAR Irradiance: 323.88 W / m ^ 2
Lux: 28078
Daily Light Integral (DLI): 114.04 mol / day
 

fishmeyer

New Member
So what do you think of these new cob lights??? I see they use less power fot he amount of light you get- What kind of spectrum do they all come in?? Whats the best one in your opinion???
 

LedTestLab

New Member
Those parameters is from 2x Citizen Clu058 - 3500K and 1 x Led Cree 6500K ...But next time will do for all 3 of Citizen, because Citizen have full info of their products, no secrets from them, everything is in datasheet. For example Termal resistance, Cree dont show information about that.
And Citizen also give liftime tests...not like China leds 50,000h just in words, but they make tests and everything is in their site or they give info if you make some order.

Spectrum is from 2700K - 6500K... I think when you make , for example 300W grow light there is 2 options in my opinion. Make it from 6 COB's if you have more grow space 2,4 m^2. If you have grow space 1,2m^2 ( 4ft x4ft) the ofcourse make it from 3 or 4 cobs.

For 6 cobs you can run cobs at 50W power. With 3 or 4 Cobs you can run them all with 100 w power.

I have example for 3 COB's growlight. 2xCitizen 3500K at 100W power each and 1 Cree 6500K with 70W power (I use Cree because I was still waiting for new Citizen COB's).

With panel like this u can get 40965 lumens. And as I understand that you need not lumens but uMols/s/m^2 or mol/day.
But umols/s/m^2 and mols/day depends from lumens ))))

For this panel at 315W power with 40965lm you get PPFD : 375.13 uMols/s/m^2 and Daily Light Integral (DLI) : 24.308 mol/day
Light must be 65cm from plants
 

BTzGrow

Well-Known Member
I just became informed a bit regarding DLI and Light Saturation. Are there any specific threads here on 420 with regards to the calculation and uses of such. Seems like the whole DLI changes the conversation with regards to gm/W to some extent. Lot of people out there using overkill in wattage and paying the power company for heat that represents waste.
 

TorturedSoul

Member of the Month: May 2009, Oct 2010, Sept 2017
It's not on the forum, but one of our members who seems to have more knowledge than half the LED grow light sellers gave me a link to an article on Purdue University's Extension website that discusses DLI (et cetera). It's a .PDF file, so you can download it and study it at leisure offline (if you like).
https://www.extension.purdue.edu/extmedia/HO/HO-238-W.pdf
 
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