Maybe I had a mis print, Im using a 1400mA driver currently and running them at 6-9in with no reflections.Those are good heatsinks but Im not that great at calculating the cooling requirements. Im using this.
CXB3590DB36V4000K 16 COBS @1.4A ON PASSIVEHEATSINK
16 SQ.FT. CANOPY 92% EFFICIENT DRIVER @15 CENTS PER KWH
Total power watts at the wall: 850.0
Cobs power watts: 782
Total voltage forward: 558
Total lumens: 154163
Total PAR watts assuming 10% loss: 430
Total PPF: 1947.9
PPFD based on canopy area: 1310.44
PAR watts per sq.ft.: 26.88
Cob efficiency: 61.03%
Power watts per sq.ft.: 48.88
Voltage forward per cob: 34.89
Lumens per watt: 197.14
Heatsink riser thickness / number of fins / fin's length: 0.3in/6/0.95in
Heatsink area per inch: 100.94 cm^2
Total heat watts: 305
umol/s/W / CRI: 4.53 / 70CRI
Heatsink length passive cooling @120cm^2/heatwatt: 363 inches
Heatsink length active cooling @40cm^2/heatwatt: 121 inches
COB cost dollar per PAR watt: $1.87
Electric cost
@12/12 in 30 days: $46.4
Electric cost @18/6 in 30 days: $69.35
Cost per cob: $50.17
Heatsink cost per inch cut: PASSIVE
Total cobs cost: $803
I wouldnt mind this though and running them higher. but the efficiency isnt where I would like it.
CXB3590DB36V4000K 16 COBS @1.75A ON 1.813 PROFILE HEATSINK
16 SQ.FT. CANOPY 92% EFFICIENT DRIVER @15 CENTS PER KWH
Total power watts at the wall: 1080.43
Cobs power watts: 994
Total voltage forward: 568
Total lumens: 176137
Total PAR watts assuming 10% loss: 491
Total PPF: 2224.23
PPFD based on canopy area: 1496.34
PAR watts per sq.ft.: 30.69
Cob efficiency: 54.86%
Power watts per sq.ft.: 62.13
Voltage forward per cob: 35.49
Lumens per watt: 177.2
Heatsink riser thickness / number of fins / fin's length: 0.3in/6/0.95in
Heatsink area per inch: 100.94 cm^2
Total heat watts: 449
umol/s/W / CRI: 4.53 / 70CRI
Heatsink length passive cooling @120cm^2/heatwatt: 534 inches
Heatsink length active cooling @40cm^2/heatwatt: 178 inches
COB cost dollar per PAR watt: $1.63
Electric cost
@12/12 in 30 days: $58.84
Electric cost @18/6 in 30 days: $88.01
Cost per cob: $50.17
Heatsink cost per inch cut: $0.66
Total cobs cost: $803
Total heatsink passive cooling cost: $352
Total heatsink active cooling cost: $117