a couple years ago kcmoxtractor had a thread on COB LED's I think he went more extensive into COB's since.
So I haven't been to this side of the forum for yrs. With some help from microbe77 I've been learning some things about COB led's, COB's simply stands for Chip On Board here's a typical looking COB LED.
Little basics that you may already know but bare with me.
Lumens are to light what
Pounds are to bananas
Gallons are to milk
Lumens let you buy the amount of light you want. So when buying your lights be it HID bulbs, LED's, COB LED think lumens, not watts. I soppose you can look at it as lumens per watt.
The brightness, or lumen levels, of the lights in your grow may vary widely more by the type of lighting your using rather than contigent on your wattage.
we are concerned with wattage only because of cost and electricity consumption. We use watts as a measuring stick of electicity consumption but other than that we're dealing essentially miliamps (mA) not watts, you'll see. Running these COB at lower mA's can greatly increase efficiency, enough you can add extra COB LED's in your grow to greater increase yeilds, hope I can explain this better as we go along but I'm new to this and just barely have a grasp on it.
I've found while trying to learn about COB's and led's is you'll hear a lot about 'efficiency' which is basically the ratio of protons (light) produced by the amount of miliamps your light is drawing, obviously the more protons per amp or miliamps the better. Does that all make sense so far?
So I know many of you are gearing up your resources about PAR watts, well you've heard of Kelvin's (the lighting industrys measurement of light color) so yes it's been known that 3500k is remarkably close to PAR (what the plant sees) and 4000k also but guys are tending more to the 3500"s because it's better for flowering, its like HPS but more blue. Here are a couple graphs the first one is a typical PAR example and the second is an example of CREE's CXB3070 COB 3500K
Edited by Hash_Man, 04 May 2016 - 09:33 PM.