I should've mentioned I'm running ~110w to each cob (1818's) at 2.1a. I needed to add active cooling! Its hard to find a warm spot with the fans now. Plant has exploded and got thirsty since I hung this light 5 days ago 15" from the tallest cola, calculator stats below.
1818 3000K90Min 2 COBS @2100 mA ON 5.88 PROFILE HEATSINK
2.75 SQ.FT. CANOPY 94% EFFICIENT DRIVER @15 CENTS PER KWH
Total power watts at the wall: 236.50
Cobs power watts: 222.31
Total voltage forward: 105.86
Total lumens: 23943.91
Total PAR watts assuming 10% loss: 65.70
Total PPF: 354.78
PPFD based on canopy area: 1388.66
PAR watts per sq.ft.: 23.89
Cob efficiency: 32.84%
Power watts per sq.ft.: 80.84
Voltage forward per cob: 52.93
Lumens per watt: 107.71
Heatsink riser thickness / number of fins / fin's length: 0.27in/14/1.0in
Heatsink area per inch: 260.01 cm^2
Total heat watts: 148.95
umol/s/W: 1.60 LER: 328.00 QER: 4.86
Heatsink length passive cooling @120cm^2/heatwatt: 69 inches
Heatsink length active cooling @40cm^2/heatwatt: 23 inches
COB cost dollar per PAR watt: $0.70
Electric cost
@12/12 in 30 days: $12.77
Electric cost @18/6 in 30 days: $19.16
Cost per cob: $23.0
Heatsink cost per inch cut: $1.74
Total cobs cost: $46.0
Total heatsink passive cooling cost: $120.06
Total heatsink active cooling cost: $40.02
IThought I would share my cob grow./ first grow ever for that matter. Day 30 into flower with 6 citizen clu 1825 over a 4.5 x 4 foot scrog canopy run at 160w each. Cobs are roughly 20-22 inches above the canopy.
