LED Tech, Veteran LED growers Forum

PSUAGRO.

Well-Known Member
^^^^^correct me if i'm wrong but spuzz told us that epistar doesn't make a 3w diode...or it can't be driven over 500ma making it a 2w diode...
either your not using epistar or Spuzz is a liar.........
 

Phaeton

Active Member
Penetration:
An LED is providing 1000 umol to the top of a plant from 6", double it to 12" and you have 500 umol. Putting this over a 24" plant ignores the lower buds.
Take the same plant getting the same 1000 umol on the top, except from 15" away. Double it to 30" and you have 500 umol. Putting this over a 24" plant will totally kick ass all the way to the bottom.

That is how penetration works. But since it costs so much for power to get 1000 umol from 15" most get a whole lot less power, put it really close and get a good bud on top and popcorn below.

UVB at top bud.jpgUVB at lower bud.jpg This is a 50" plant at 50 days, note the size of the lower bud, more than four feet from the light. The sidelights did not make the bud big, UVB stunts growth. The LED's provide 800 umol at 18", the max the plants can handle in the system I use. That is still 400 umol at three feet, more than the max of some budrooms I have visited.

It depends on the goal of the gardener, the extra 15% of yield per square foot of grow area make it worth it to me. Growers that do not have to heat up the growroom during -45 degree ambient temperatures may have more growing space available and this will matter less.
 

PSUAGRO.

Well-Known Member
Sorry Phaeton maybe I should clarify......by amplifying the light your losing coverage and total output from the led....yes your amplifying the spectra directly under the lamp, but at a cost(cant have your cake and eat it too buddy).
I may have slept through most of my Physics classes in school...but I do remember that when light goes through ANY medium (glass/acrylic/plastic(secondary lense))it immediately loses like 10-15% of its output.......any physics majors in here/to clarify or tell me i'm wrong???...
 

Eraserhead

Well-Known Member
Lenses have disadvantages and advantages. Mostly disadvantages when used in Chinese LED panels.

This is why:

You have the LED chip > optical lens > tempered glass cover.

Each layer of glass (or plastic) the light has to go through, it loses light. 10% at the optical lens, and 10% more at the tempered glass cover. You get 81% of your light.

If the LEDs are already 90 degree, there is no need to add additional 90 degree lenses. Most LEDs from China start at 90 degrees or 120 degrees. Lately mostly 90.

If you add all 60 degree lenses, then you have too much intensity and much less of a lighting area, and you will get leaf bleaching, even with smaller than 200 watt LEDs at 24" above the plants can cause bleaching.

If you mix some 60s and some 90s properly, or other degrees between, then you'll get some advantages of using lenses.

The main reasoning behind secondary lenses is so the grower doesn't have to rely on reflecting light back to the plants as much. It's a really good idea if the lenses used were the proper degree, and even better if the tempered glass cover can be removed.
 
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