this is why i said these citi are better in the high wattage applications,not down around 50w
from above post^^^^..... Cob efficiency: 37.09%
Power watts per sq.ft.: 49.62
Voltage forward per cob: 49.62
Lumens per watt: 124.24
am i missing something? those are terrible at 50w
would be better off with 3 x 315w cmh about the same price and you could just upgrade every year as tech gets better right ?
Ya, I thought the 1818's were supposed to operate better at higher loads too, but it doesnt seem to be the case? I guess thats why mine are sitting in a drawer instead of being lit up. They need to run at 400mah to reach 40% efficiency
1818 3500K90Min 50 COBS @2500 mA ON 1.813 PROFILE HEATSINK
50 SQ.FT. CANOPY 94% EFFICIENT DRIVER @15 CENTS PER KWH
Total power watts at the wall: 7177.25
Cobs power watts: 6746.61
Total voltage forward: 2698.64
Total lumens: 711622.37
Total PAR watts assuming 10% loss: 1911.82
Total PPF: 10217.62
PPFD based on canopy area: 2199.63
PAR watts per sq.ft.: 38.24
Cob efficiency: 31.49%
Power watts per sq.ft.: 134.93
Voltage forward per cob: 53.97
Lumens per watt: 105.48
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: 4655.16
umol/s/W: 1.51 LER: 335.00 QER: 4.81
Heatsink length passive cooling @120cm^2/heatwatt: 5534 inches
Heatsink length active cooling @40cm^2/heatwatt: 1845 inches
COB cost dollar per PAR watt: $0.60
Electric cost
@12/12 in 30 days: $387.57
Electric cost @18/6 in 30 days: $581.36
Cost per cob: $23.0
Heatsink cost per inch cut: $0.66
Total cobs cost: $1150.0
Total heatsink passive cooling cost: $3652.44
Total heatsink active cooling cost: $1217.70
1818 3500K90Min 2 COBS @400 mA ON 1.813 PROFILE HEATSINK
2 SQ.FT. CANOPY 94% EFFICIENT DRIVER @15 CENTS PER KWH
Total power watts at the wall: 40.46
Cobs power watts: 38.03
Total voltage forward: 95.08
Total lumens: 5115.89
Total PAR watts assuming 10% loss: 13.74
Total PPF: 73.45
PPFD based on canopy area: 395.33
PAR watts per sq.ft.: 6.87
Cob efficiency: 40.15%
Power watts per sq.ft.: 19.02
Voltage forward per cob: 47.54
Lumens per watt: 134.51
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: 22.82
umol/s/W: 1.93 LER: 335.00 QER: 4.81
Heatsink length passive cooling @120cm^2/heatwatt: 27 inches
Heatsink length active cooling @40cm^2/heatwatt: 9 inches
COB cost dollar per PAR watt: $3.35
Electric cost
@12/12 in 30 days: $2.18
Electric cost @18/6 in 30 days: $3.28
Cost per cob: $23.0
Heatsink cost per inch cut: $0.66
Total cobs cost: $46.0
Total heatsink passive cooling cost: $17.82
Total heatsink active cooling cost: $5.94