Cree and Epiled are different companies. Epiled is considered a good, middle grade diode made in Taiwan and China. Cree, Luxeon, Osram are considered high end in color diodes, and Cree, Bridgelux, Citizen, Nichia and Samsung in white diodes. Most if not all have factories in China, but none of the top grade manufacturers produce solely in China (at this point). They maintain manufacturing facilities in their home countries of Taiwan, South Korea, Japan and US for economic leverage and quality control reasons, perfecting processes at home and then implementing them in their China ops.
There are a lot of “boards” out there these days. I agree with @HalfBee, the circuit engineering behind the board is critical. As is the engineering of the PCB. Anyone can solder chips to PCB blank. But without good engineering and quality production, grower misery will follow as diodes and whole strings burn out, thermal runaway set in, and $100 boards that should last 50,000 hours are turned to toxic waste in a few months.
@21stg.com hasn’t listed his board specs. I assume at 320 diodes of LM561C it tops out at 150w. The rest of the specs he mentions are taken from Samsung’s data on there chips, and don’t reflect actual performance on the PCB. Running a 150w board at 50 watts will definitely boost efficiency, but at the cost of 3x more boards. Good for the board salesman, board buyers not so much. Running at 1/3 rated power also avoids heat and current balancing issues in poorly designed boards that would otherwise toast them at full power.
SolStrips are rated at 48w, and built to run at 48w all day long - delivering up to 200 lumens/watt over a 50,000 hour lifetime. For $20. At 96 LM561C chips per, three would about equal one of these COB-beaters, but with the added flexibility of spreading out the light field to fit your space and deliver an even “blanket” of light across the canopy, with any mix of spectrum you prefer to create. The rest of the specs are available on the DIY with LED strips thread.
Coming in two weeks: 2700K and 3500K spectrum strips.
-b420