sad news folks --- i got in touch with a friend who will lend me a 650W or 1000W HPS (has them in the multiples) i'll just buy a new bulb. due to these cost savings, i will have to postpone this prospective COB build -- who knows, maybe there'll be better tech in 3 months :/ i do have a viparspectra...

oh yea and lumen output 1xCXB @ 2A is >10,000 lumens for easy comparison 2x CLU @2x1A is >10,000 lumens too so the lights (assuming similar spectrum) are essentially as efficient as each other (they convert same amount of high-energy electrons into photons) that being said, you'd need to buy roughly...

definitely the CXB3590s from the clu048-1212 specs: https://ce.citizen.co.jp/lighting_led/dl_data/datasheet/en/COB_5/CLU048-1212C4_P3700_0516.pdf, it operates at 35V so lets assume its the same operating voltage as CXB but they can only be driven at a max of 2700 ma ( the thing could fry if driven >...

also looking at https://www.cree.com/led-components/med ... XB3590.pdf
according to the relative luminous-flux diagram,

if active heatsink, and can run about 20 degrees cooler -- can get 5-15% more output

if the actives run cooler, they offer a lot more advantages than just cost...

the powersupply is 36V constant voltage, 200W
the lights themselves are being run at ~66 W a piece

one would veg 3"x3" fine ( < 1mx1m )
two of these would flower a 4"x4" which is > than 1mx1m

100W of cob is good to flower up to 2'x2' space from what i gather.

So all these diy builds are going for the Optic 1 XL spotlight designs, with the large 180mm (or 150mm on the 54W builds). These heatsinks are expensive af -- >$50 for the 180mm if you want to passively cool a 100W COB. Has anyone used the active coolers? Plain ol' CPU + fans? I'm thinking of using ...