I am embarrassed that I just found something out, even with me being into DIY LEDS for many years.
So, when I started some years ago I got this fixture with 4x CXB3590. (My growing area is only 1.20x0.60, depending). I got the MW HLG-240h-C1750A since I figured a little more headroom of up to 1750mA for each COB would be good)
Two years in I decided to expand my fixture (for better spread in my greenhouse), so I made a second strip, got 2 more CXB3590 and moved one COB from the 1st strip to the second strip. Now I have 2 strips with 3 COBs each, with the two strips connected parallel, all with the one driver.
Since the two strips are now parallel, this means that the driver provides now half the current for each strip.
So instead of providing 875-1750mA for each of 4 COBS (using the pot), I am now providing 437-875mA for each of 6 COBs.
But I just found this is less than optimal and I could get more out of my light with a different driver. Instead of the 1750mA driver, I could have the 1050mA driver, and run the 6 in series (216V). And then I could run each COB at 525-1050mA. (I figure about 1050mA is optimal for each COB, I like them running low, at about 40W max for each)
I could get the same result (run each at max. 1050, rather than 875) with the 2100mA driver and keep my current configuration and leave the two strips parallel like now. (Which would be "better", and why? Would it matter?)
