Bosgrower
Well-Known Member
First, heartfelt thanks to all the contributors that have so diligently compiled the wealth of information here on elsewhere, with special shoutouts to SupraSPL and Growmau5 for their extraordinary efforts to provide detailed DIY information.
It's been 50 years since I've had to deal with Ohm's law, Planck constants, or µ as a prefix on anything ... but after wading through it all I feel marginally competent to build a COB system for a 4x4 reflective grow tent. So thank you.
That said, I'd appreciate your thoughts on my plans.
I'm planning a 12 COB fixture ... 8 CXB3590 CD 3500K 36v and 4 CXA 3590 CD, DB 4000K 36v configured as 3 4 COB arrays
I'll power them with 2 MW HLG 320H-C1400B (6 COBs each ... the driver supplies 230v) and either a Solar Storm dimmer or 2 10K potentiometers (Yes,I'm old but I can still solder)
I've ordered 12 of the KB 90 reflectors since they're cheap and 4 of the 120 degree lenses with appropriate mounting hardware so I can experiment with even light distribution.
I'm getting the pre-drilled KB 133mm passive heat sinks because at $10.60 each, even with the shipping they're cheaper than any other passives I could find.
If anyone has a better suggestion I'd love to hear it ... Chinese New Year is coming up and KingBrite is shutting down from Jan 15th to Feb8th so I need to get this placed ASAP.
Although I'm not sure the DIY calculator is spot on, here are some numbers for the array at .7ma, 1.05ma, and 1.4ma
CXB3590CD36V3500K 12 COBS @1.4A ON 2.08 PROFILE HEATSINK
16 SQ.FT. CANOPY 95% EFFICIENT DRIVER @10 CENTS PER KWH
Total power watts at the wall: 616.84
Cobs power watts: 586
Total voltage forward: 419
Total lumens: 106968
Total PAR watts assuming 10% loss: 297
Total PPF: 1381.05
PPFD based on canopy area: 929.09
PAR watts per sq.ft.: 18.56
Cob efficiency: 56.34%
Power watts per sq.ft.: 36.63
Voltage forward per cob: 34.89
Lumens per watt: 182.54
Total heat watts: 256
umol/s/W / CRI: 4.65 / Estimated
CXB3590CD36V3500K 12 COBS @1.05A ON 1.813 PROFILE HEATSINK
16 SQ.FT. CANOPY 95% EFFICIENT DRIVER @10 CENTS PER KWH
Total power watts at the wall: 449.47
Cobs power watts: 427
Total voltage forward: 406
Total lumens: 83265
Total PAR watts assuming 10% loss: 236
Total PPF: 1097.4
PPFD based on canopy area: 738.27
PAR watts per sq.ft.: 14.75
Cob efficiency: 61.5%
Power watts per sq.ft.: 26.69
Voltage forward per cob: 33.85
Lumens per watt: 195.0
Total heat watts: 164
umol/s/W / CRI: 4.65 / Estimated
CXB3590CD36V3500K 12 COBS @0.7A ON 2.08 PROFILE HEATSINK
16 SQ.FT. CANOPY 95% EFFICIENT DRIVER @10 CENTS PER KWH
Total power watts at the wall: 289.47
Cobs power watts: 275
Total voltage forward: 393
Total lumens: 57032
Total PAR watts assuming 10% loss: 158
Total PPF: 734.7
PPFD based on canopy area: 494.26
PAR watts per sq.ft.: 9.88
Cob efficiency: 64.01%
Power watts per sq.ft.: 17.19
Voltage forward per cob: 32.72
Lumens per watt: 207.39
Total heat watts: 99
umol/s/W / CRI: 4.65 / Estimated
It's been 50 years since I've had to deal with Ohm's law, Planck constants, or µ as a prefix on anything ... but after wading through it all I feel marginally competent to build a COB system for a 4x4 reflective grow tent. So thank you.
That said, I'd appreciate your thoughts on my plans.
I'm planning a 12 COB fixture ... 8 CXB3590 CD 3500K 36v and 4 CXA 3590 CD, DB 4000K 36v configured as 3 4 COB arrays
I'll power them with 2 MW HLG 320H-C1400B (6 COBs each ... the driver supplies 230v) and either a Solar Storm dimmer or 2 10K potentiometers (Yes,I'm old but I can still solder)
I've ordered 12 of the KB 90 reflectors since they're cheap and 4 of the 120 degree lenses with appropriate mounting hardware so I can experiment with even light distribution.
I'm getting the pre-drilled KB 133mm passive heat sinks because at $10.60 each, even with the shipping they're cheaper than any other passives I could find.
If anyone has a better suggestion I'd love to hear it ... Chinese New Year is coming up and KingBrite is shutting down from Jan 15th to Feb8th so I need to get this placed ASAP.
Although I'm not sure the DIY calculator is spot on, here are some numbers for the array at .7ma, 1.05ma, and 1.4ma
CXB3590CD36V3500K 12 COBS @1.4A ON 2.08 PROFILE HEATSINK
16 SQ.FT. CANOPY 95% EFFICIENT DRIVER @10 CENTS PER KWH
Total power watts at the wall: 616.84
Cobs power watts: 586
Total voltage forward: 419
Total lumens: 106968
Total PAR watts assuming 10% loss: 297
Total PPF: 1381.05
PPFD based on canopy area: 929.09
PAR watts per sq.ft.: 18.56
Cob efficiency: 56.34%
Power watts per sq.ft.: 36.63
Voltage forward per cob: 34.89
Lumens per watt: 182.54
Total heat watts: 256
umol/s/W / CRI: 4.65 / Estimated
CXB3590CD36V3500K 12 COBS @1.05A ON 1.813 PROFILE HEATSINK
16 SQ.FT. CANOPY 95% EFFICIENT DRIVER @10 CENTS PER KWH
Total power watts at the wall: 449.47
Cobs power watts: 427
Total voltage forward: 406
Total lumens: 83265
Total PAR watts assuming 10% loss: 236
Total PPF: 1097.4
PPFD based on canopy area: 738.27
PAR watts per sq.ft.: 14.75
Cob efficiency: 61.5%
Power watts per sq.ft.: 26.69
Voltage forward per cob: 33.85
Lumens per watt: 195.0
Total heat watts: 164
umol/s/W / CRI: 4.65 / Estimated
CXB3590CD36V3500K 12 COBS @0.7A ON 2.08 PROFILE HEATSINK
16 SQ.FT. CANOPY 95% EFFICIENT DRIVER @10 CENTS PER KWH
Total power watts at the wall: 289.47
Cobs power watts: 275
Total voltage forward: 393
Total lumens: 57032
Total PAR watts assuming 10% loss: 158
Total PPF: 734.7
PPFD based on canopy area: 494.26
PAR watts per sq.ft.: 9.88
Cob efficiency: 64.01%
Power watts per sq.ft.: 17.19
Voltage forward per cob: 32.72
Lumens per watt: 207.39
Total heat watts: 99
umol/s/W / CRI: 4.65 / Estimated
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