Hey everyone, been a while :) I know KCMO has a killer COB thread he's been working on, and I didn't want to clutter up his thread. That thread is a treasure trove of good information, and some grower skill.
I am gearing up to get a 4x4 going and I am still extremely disappointed in off the shelf LED offerings. This frustration is leading me down the DIY path.
This thread will be about that journey.
So, to be honest - my interest in COB is not very high. They do well, plenty of people are using them with great results- but the efficiency is not that great, and they act like a single point light source. Passive heat sinks need to be huge, and even active heat sinks tend to be pretty bulky.
My intuition tells me the high power single diode approach has still not been mastered - and they become cumbersome projects for the DIY crowd. You have complete control of the photon spread, and the photon density can be equally high as a COB with equal or better efficiency.
Also, there is a new hybrid approach in the game. The proprietary name is "Quantum Boards". https://horticulture.../quantum-boards
These are basically a compromise from the ease of DIY of a COB, but photo distribution similar to a more traditional "blurple" panel approach.
Unfortunately these are out of stock right now, and apparently when they come back in stock the LEDs will be from a higher BIN... lower forward voltage with a higher output.... combining to provide a 10% efficiency boost (4% from lower voltage, 6% from better output). I am sure these will also sell out quickly and be out of stock again.
Unless I can get a hold of some of these QBs, the plan will be to design a more traditional panel. Even if I do get some QBs I would want to add additional 660, 730, and maybe even 840 diodes - because flowering plants love these.
Any who, just wanted to say hi to everyone and get something started. I bought some cheapo panels for veg lighting while I get rolling.