Mullumbimby
Well-Known Member
Thanks guys.
Temperature problem with CXB Cobs
sixixix
Well-Known Member
My setup is kind of overkill for my limited space. When I measured the surface temp on my buds, they were around 100-105f. My ambient temps were never higher than 85f, even when measured just over the canopy, under a cob. I had to lift my lamps and dim them down a bit to get the surface temps down to 80-85f.
CXB3590CD36V3500K 8 COBS @1.4A
0.5 SQ.M. CANOPY 91% EFFICIENT DRIVER
Total power watts at the wall: 429.67
Cobs power watts: 391
Total voltage forward: 279
Total lumens: 71373
Total PAR watts assuming 10% loss: 198
Total PPF: 920.7
PPFD based on canopy area: 1841.4
PAR watts per sq.m.: 396.0
Cob efficiency: 56.34%
Power watts per sq.m.: 782.0
Voltage forward per cob: 34.89
Lumens per watt: 182.54
What's better, dimming and running them closer to the canopy, or raising them while running at full power?
CXB3590CD36V3500K 8 COBS @1.4A
0.5 SQ.M. CANOPY 91% EFFICIENT DRIVER
Total power watts at the wall: 429.67
Cobs power watts: 391
Total voltage forward: 279
Total lumens: 71373
Total PAR watts assuming 10% loss: 198
Total PPF: 920.7
PPFD based on canopy area: 1841.4
PAR watts per sq.m.: 396.0
Cob efficiency: 56.34%
Power watts per sq.m.: 782.0
Voltage forward per cob: 34.89
Lumens per watt: 182.54
What's better, dimming and running them closer to the canopy, or raising them while running at full power?
MrTwist1
Well-Known Member
It depends if you like giving your money away to the utility company lol. In fairness you might get slightly better uniformity by running the light higher at more power, but possibly not.
VegasWinner
Well-Known Member
are you exhausting hot air outside the room the tent is in? If not you are recyceling hot air getting hotter. you are at 50w/sf so you might consider moving your lights up more and exhaust the hot air and replace with passive intake of fresh outside air. . you might consider dimming both drivers to 50% which will put you at 25W/sf for vegging which is fine. work out heat exhaust issue before bloom and you will be fine. I would move the lights up 18" at least. peace
sixixix
Well-Known Member
Seems like i forgot about this thread 
The CXB's are for flowering only. The whole floor of the flowering cab is a passive intake. My setup needs to be super stealthy, which limits what solutions I can use for ventilation. My cab is venting into a 180 sqft room. This room is ventilated with a bathroom ventilator and a passive air intake. Now that the summer is over I'm running at full power again, and the surface temps on the tallest buds doesn't get any higher than 82f. Next year I'll upgrade the ventilation in the room itself, and just dim down it I still need to.
I noticed that the trichomes on the tallest buds degraded when the surface temps were too high. The air temp was pretty spot on for a LED grow, so it might be a good idea to check the surface temps if you are growing with cobs in a small space like mine.
The CXB's are for flowering only. The whole floor of the flowering cab is a passive intake. My setup needs to be super stealthy, which limits what solutions I can use for ventilation. My cab is venting into a 180 sqft room. This room is ventilated with a bathroom ventilator and a passive air intake. Now that the summer is over I'm running at full power again, and the surface temps on the tallest buds doesn't get any higher than 82f. Next year I'll upgrade the ventilation in the room itself, and just dim down it I still need to.
I noticed that the trichomes on the tallest buds degraded when the surface temps were too high. The air temp was pretty spot on for a LED grow, so it might be a good idea to check the surface temps if you are growing with cobs in a small space like mine.
nevergoodenuf
Well-Known Member
It looks like you might need a small clip fan in there to get air moving through the leaves better. Nice little setup.
sixixix
Well-Known Member
Thanks! I put one in a couple of weeks ago
Diskokobaja
Well-Known Member
Can somebody help me..I got same problem as this dudes..
I have 2 diy leds..
1st is 3070 3000k 80 cri 4 cobs on meanwell 185 fans are artic cool 64
2nd 1212 clu048 90 cri 3500k 4 cobs on meanwell 185or 186 ? I'm not sure.. fans are artic cool 11
extractor prima klima 125 400cfm outtake hose is put on open window so hot air isnt in the room...
my tent temps are 5-7c higher than enviromentt temps...I bought even mobile ac unit (obvious shitty) but it doesn't help a lot.. Temps in tent are ranging from 30(86f)-33c (92f).. Driver are warm not hot 8about 30c (I put chinese thermometer probe on it)..
When is on max power ,my extractor scuk in the walls of the tent, so air circulation is good...
I have 2 diy leds..
1st is 3070 3000k 80 cri 4 cobs on meanwell 185 fans are artic cool 64
2nd 1212 clu048 90 cri 3500k 4 cobs on meanwell 185or 186 ? I'm not sure.. fans are artic cool 11
extractor prima klima 125 400cfm outtake hose is put on open window so hot air isnt in the room...
my tent temps are 5-7c higher than enviromentt temps...I bought even mobile ac unit (obvious shitty) but it doesn't help a lot.. Temps in tent are ranging from 30(86f)-33c (92f).. Driver are warm not hot 8about 30c (I put chinese thermometer probe on it)..
When is on max power ,my extractor scuk in the walls of the tent, so air circulation is good...