Hello, The main disadvantage of the leds is their low penetration. Whereas HID bulbs are praised for their penetration. Then a question poses in my noggin, what the hell does penetration depend on? Only one clear answer I see so far- a whole bunch of photons from a single point (line) in space. So I propose this, using a led with the highest light output from the smallest area. So far i found led COBs from the likes of cree, samsung, etc. A cob is mere 9 square centimeters but sucks out a lot of wattage, up to ~100W So how about using a bunch of these "modules" like 10 COBS on separate heatsinks with fans and power supplies for each and put them not only above the plants, but also around the room so as to have light poins even below canopy level for e.g. in the corners of the room, depending how big the room is, maybe even have a column with cobs in the middle blasting sideways as well. So, do you think that using COBs would help with penetration vs regular panels? ***Now i know that im ignoring a main aspect of using only the needed wavelengths, but find me a respectable panel with quality leds and usage of ~100W at the plug which is not a damn ufo 30+ cm across.
LEDs dont have penetration problems only shit LEDs have penetration problems. here are a list of the lights i have used that have no penetration. Mars 2 fake 5 watt, Kind L600, prosource led 90 watt ufo, california lightworks solar flare 200 and chloroba c2. these lights i have used and they all suck. anyone who has compared these to HID has not really compared HID to LED yet. you are right the problem with the cob is the spectrum. most of them are closer to the 600nm wavelength like HPS. the problem with that is you are getting your plant to grow mainly using Chlorophyll B. when you get you plant firing on Chlorophyll A everything is better. spend the money buy a real LED light and enjoy.
Penetration has a lot more to do with how many "point sources" of light you have vs the actual chip/diode/light you are using... Penetration is a word a lot of growers like to throw out there, but don't understand what it actually means. If you have 1 light above a leaf, then the shadow is reflected directly downward... now if you had that same leaf, but spread the light out to be 3 sources of light, offest from each other, directly above the leaf, you will get better penetration *(the shadow size will be reduced) ...even if the total wattage of the 1bulb is equal to the total wattage of the 3 bulbs....the more "point sources" you have, or origins of light...the better the penetration... so with this being said, distance between point sources comes into importance. For instance...if you took a 600w HID vs 2 400w HID lights.... a 600w puts out around 90,000 lumens, and a 400w puts out around 40,000 lumens... So one would think that a 600w HID would give better penetration vs 2x 400w HID lights....not true...even though the luminous intensity is higher with the 600w light, as well as it has better luminous efficiency....the penetration of the 400w HID's would be better because you have light ommited from 2 point sources vs one...limited the "shadowing" of the leaves...therefore the shadow sized would be decreased due to having 2 point sources vs 1 overhead... FYI...COB lighting is not good for horticulture.... COB was designed to make LED lighting cheaper to manufacturer, and to squeeze chips into a small area. But as far as plant lighting, you are better off going with individual diodes in a matric array, not COBS. Also, with most multi color cobs....the individual chips are Epiled or Epistar which on the chart of luminous efficiency are far from the best. Most COB designed LED panels have very poor thermal management which also leads to failing components, faster degading of the chips efficiencies, and less of a lifetime.
I am using 2 x 200 watt Chip LED's there are about 5 different color diodes on the chip. I have just started using Chip LED's they are tuned into the desired veg/flower colors. You seriously need sunglasses to look at it when t is on and with the UV/UVB light spectrum mixed in there, you better. I wanted to do a DIY Chip, but all the high watt chips available are one single color. The few that are available, in a mixed spectrum, are so highly priced it is better to buy a assembled kit. And from the reviews I have read, Asia is the place to go(this is for high watt COB's). My plants just explode under these lights, but you seriously need to keep them at the recommended distance of 2-3 feet. Or they will show signs of sun burn Now knowing full well this is uncharted territory/tech, I just had one of lights stop working, 2 days ago. Lucky there is a 3 year warranty was easy to use. Customer service was so good that I order two more 200 watt COB led's. I also realize one or even 2 will stop working by the new year, but if my $$ will go towards a better end product I will try it out. But from the results so far I think it is worth a honest effort. I have them in a support lights for my 250w HPS. Those lights mixed together are encouraging and I think meant to be. l
I want to buy a plasma LED so bad though, I can taste it. Only reason Iam using COB atm is I'm to cheep to shell out $1500 for a 300 watt light. Anyone has any experiences with them? The must have good penetration, even for 300 watts.