re: GrowLEDHydro 300W LED vs. 400W HID Demonstration
SUN- to say the plants look fantastic is an understatement. The LED side is showing the potential that this technology has in store for horticultural applications. The unit you have there on test is obviously doing something right. I do have a few comments from the quote below- you did say "Or we coud discuss them here".
This is copied from GLH's website as regards the spectrum:
So, how does the Spectra LED light spectrum grow light work?
In a nutshell it is a series of 9 different colored 3 watt LEDs (Light Emitting Diodes) that emit 12 wavelengths of light in all visible colors of the light spectrum.....
....Or, we could also discuss them here
I understand customers wanting to know the exact spectrum of the light they are purchasing, and I also can appreciate the vendor not wanting to reveal the exact formula to their success, especially in an industry where knockoffs abound.
I can respect both of those desires.
OK- I will get the venting over with early. Like '1234a5678b', I too would be interested
in seeing the spectral output of the light- I don't think we are advancing the conversation of what works and what doesn't within the community if we don't know what we are talking about, ESPECIALLY WITH LED TECHNOLOGY- but I totally respect your decision or the MFR's not to disclose. I understand the state of product development- there are a few that actually
'develop' and whole bunch of parasite fucks that copy. In America it is ALL about cheap-cheap-cheap and not about innovation, quality, or brand loyalty- the justification to invest the development money and then later try and recoup it is difficult when your product is practically knocked off at a cut rate price before you are even able to get it out the door. So I understand, I do- it is just that this is what you are really paying for and even the HID guys will give you a spectral emission chart, and it's not like your going to able to patent a portion of the EM spectrum anymore than you can patent water or pussy ( I tried- damn those patent people, no sense of humor!).
OK- I am going to rag a little, but just a bit, becuase statements like these are going to be confusing and misleading to the customer-
In a nutshell it is a series of 9 different colored 3 watt LEDs (Light Emitting Diodes) that emit 12 wavelengths of light in all visible colors of the light spectrum.
It is a physical impossibility to get 12 different peak wavelengths from 9 different 'colored' LED dies- each die will have a characteristic peak wavelength, which is what we are concerned with. OK- there may be more in the paragraph that I take issue with but I have had my say on that one and will leave it at that.
Here is the deal that I really want to talk about and I can see that there are a lot of other people that want to educate themselves about this LED stuff. I am afraid we are heading down the same techno babble rat hole that find ourselves in with HID technology and the 'lumen'- however with LED I can see the new confusing term is the Watt. With HID and CFL they throw around the terms
'lumen' and
'color temperature' like thay have any bearing at all on the quality of light being generated with regards to the photosynthetic process, when in fact, they don't. I could design a light source 30 different ways from Sunday and adjust the 'lumens' or 'color temperature' around to whatever you want it to be- it does not necesarily mean the light will be any better or worse source of photosynthetically active light. For all practical purposes, PAR is about a useless term as well.
OK, so anyway, now we are on the new LED technology, and the buzz terms are
"3W LED's" or
"1W LED's"- trust me, believe me- we are heading down a terminology rat hole which is not going to tell us a damn thing about the quality of the light
(wavelength/ amplitude), how well the light performs, or the actual radiant output power of the light (what you are actually paying for- photons). First off- the term "1W LED" is loosely used in the LED industry to describe an LED which is approximately 1mm^2. This is the size of the dies at the current state of mass production which offer peak efficiency in output and the best yield off the wafers. Yes- you can make the dies bigger, but efficiency/ yield suffers. You can make them smaller and gazillions of these are obviously available, but again, efficiency suffers.
Why is it referred to as a "1W LED"- because all the test data is generated with 350mA drive current- that times the Vf of the device yeilds approx. 1W. Thermal management issues become extremely tricky when current density through the die is increased above this level- none-the-less, enter the so called "3W LED"- this is your same good old friend Mr. 1W LED driven with 1 amp of current instead of 350mA.
IT IS THE SAME 1MM^2 DEVICE. Again- thermal issues must be addressed when doing this to an LED- I am skeptical about large chunks of aluminum and banks of fans- but whatever, that is just me. Also- true, high quality 1W LED dies from respectable MFR's, i.e. Cree or Bridgelux, are not available to cover the entire visible spectrum- that is just a fact.
Now the situation with LED's gets even more effed up and confusing because not all 1mm^2, 1W dies are the same- not by a long shot- not even within the parts of the same manufactruer. The difference between red and blue LED dies is in process and materials, and the best of the red dies have <maybe> 1/3 the radiant output power as the best of the blue. Add to this that LED dies are incredibly inconsistant coming off the wafers in fabrication- they have to be binned according to radiant output power (among other things)-
with LED there is simply no way to know what you are buying unless the fixture manufacturer gives you a spectral emission chart. I think every LED vendor should include this as a matter of course.
OK- so there you have it- there is my gripe- thanks for your patience. I have a portable spectroradiometer around here somewhere- I don't think the panelized LED's would work well in the integration sphere- it would fit in my largets integration sphere, but the dtector head is not set up for that large a light source. If I can dig it up, and if it still works, maybe we can get some shots off these LED units and see what we are really looking at, if anyone is interested. Except right now I am stuck in jack-boot BFE Texas, yeehaw.
