Bosgrower
Well-Known Member
No problemYou want to show us your design? I got COBs on the brain and I'd love to see what you have and do a price/eff analysis to get better at this.
My design is for a 4x4 flower tent.
I have 3 42" bars with 4 COBs each using passive 140mm anodized pin heat sinks.
The COBs are all CXB 3590 CD CRI 80s. I have 90 degree reflectors for the 3500K and 120 degree lenses for the 4000K. There are 8 3500K and 4 4000K for blue balance in a diamond pattern. I have 2 MW HLG-320H-C1400B drivers powering 6 COBS each with potentiometer dimming. I mounted the drivers outside the early veg area (I'm using the 4000K in a temporary bar by themselves at the moment) and I'm still deciding on a final configuration.
Part of that is due to a decision to make the 4x4 a veg tent and put up a 5x5 for flower ... so I'll probably reconfigure things and add more COBs.
The present fixture (with all 12 COBs at max power) draws about 610w at the wall and puts out just over 100K lumens at 56% efficiency (342w generate photons, 268w generate heat).
I could change the drivers to 3 MW HLG-320H-C2100B and bump these 12 to 960w at the wall for 145K lumens, but efficiency would drop to 49% so my preference is to add another 4 COB bar and another 1400ma driver and maintain efficiency. The 16 COB fixture would pull 830w at the wall, for 143K lumens so there'd be less cost and less heat (456w vs 341w) going forward.
For purposes of comparison, a 1000w HPS pulls 1000w at the wall and generates 145K lumens
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