So I am in the process of getting all the info I can about cobs, drivers and heatsinks to design and build a cob system in my 2x4x5 tent
I have been looking around trying to find info about calculating or finding test info regarding the ppf of different cobs from cree and bridgelux to try and get the most bang for my buck.
If anyone could help..... I've been watching a lot of the YouTube stuff Growmau5 has posted but all the new info is a bit overwhelming....
There is a thread on here called DIY COB Calculator, you can download 2 small apps (for pc) from the guys signature at the end of any of his posts. One is for cree, vero and some others (although last generation not new ones) The other is for citizen chips.
You can input your desired cob count and amperes and space and it will tell you the PPFD as well as efficiency.
It looks like this (using one of Key4s Examples)
1212 3500K80Min 8 COBS @1400 mA ON 1.813 PROFILE HEATSINK
8 SQ.FT. CANOPY 95% EFFICIENT DRIVER @11 CENTS PER KWH
Total power watts at the wall: 428.17
Cobs power watts: 406.76
Total voltage forward: 290.55
Total lumens: 61364.59
Total PAR watts assuming 10% loss: 164.86
Total PPF: 881.09
PPFD based on canopy area: 1185.49
PAR watts per sq.ft.: 20.61
Cob efficiency: 45.03%
Power watts per sq.ft.: 50.85
Voltage forward per cob: 36.32
Lumens per watt: 150.86
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: 223.72
umol/s/W: 2.17 LER: 335.00 QER: 4.81
Heatsink length passive cooling @120cm^2/heatwatt: 266 inches
Heatsink length active cooling @40cm^2/heatwatt: 89 inches
COB cost dollar per PAR watt: $0.58
Electric cost
@12/12 in 30 days: $16.96
Electric cost @18/6 in 30 days: $25.43
Cost per cob: $12.0
Heatsink cost per inch cut: $0.66
Total cobs cost: $96.0
Total heatsink passive cooling cost: $175.56
Total heatsink active cooling cost: $58.74
For what its worth you can run them softer than that.
