Cpl questions

iv been searching but can't find my answer,
What is the ppfd of 9 cxb 3590 at 50w in a 4x4 space and do reflectors change this at the same distance?

Also to dim my drivers do I need to use the internal pots, can I not attach a dimmer to the mains side and use that to dim them all?

Thanks guys

No one able to help me with this, iv added reflectors and dimmed the lights to 120w per 3 bar so will be 360w draw from the wall, lights around 18-20 inches above the canopy

CXB3590CD36V3500K 9 COBS @1.05A ON 12 PROFILE HEATSINK
16 SQ.FT. CANOPY 94% EFFICIENT DRIVER @1 CENTS PER KWH
Total power watts at the wall: 340.43
Cobs power watts: 320
Total voltage forward: 305
Total lumens: 62400
Total PAR watts assuming 10% loss: 177
Total PPF: 823.05
PPFD based on canopy area: 553.7
PAR watts per sq.ft.: 11.06
Cob efficiency: 61.5%
Power watts per sq.ft.: 20.0
Voltage forward per cob: 33.85
Lumens per watt: 195.0
Heatsink riser thickness / number of fins / fin's length: 0.3in/31/1.0in
Heatsink area per inch: 558.7 cm^2
Total heat watts: 123
umol/s/W / CRI: 4.65 / Estimated
Heatsink length passive cooling @120cm^2/heatwatt: 26 inches
Heatsink length active cooling @40cm^2/heatwatt: 9 inches
COB cost dollar per PAR watt: $2.42
Electric cost @12/12 in 30 days: $1.73
Electric cost @18/6 in 30 days: $2.34
Cost per cob: $47.62
Heatsink cost per inch cut: $5.0
Total cobs cost: $429
Total heatsink passive cooling cost: $130
Total heatsink active cooling cost: $45

You don't gain or lose PPFD using reflectors, you just control where the light goes.

I would not attach a dimmer to the AC side.

Wow thank you very much
Iv dimmed with the internal pots to 120w per bar of 3, draw from the wall 362w.
On pin fin heatsinks 6 72v on hlg 120 700a and 3 36v on a 120 1400a.
Dimming them just this bit has shed a load of the heat.
So at this power what would be a good starting point for distance from canopy at this power level? Plants are only 2-3 ft do doesn't need major penetration. Sorry for the questions but glad to have gone from the hps hopefully this keeps me away.

Thanks again for that wish I could like posts but too new I guess

Just noticed the ppfd is low, is that due to the 4x4 space? I grow in a 1 metre tray in the tent and with negative pressure the space becomes around that.
The ppf is that over a metre2 I take it??
So in a 1x1m space it's 800 odd ppfd am I correct?
Should I just leave them on full draw or would it be way to much. Each bar pulls between 170-180w from the wall lol

Thanks

All that depends on how long you want to grow them out. I would start out at 18" and see how it goes from there.

How do you mean how long I want to grow them out? :/. I grow autos and mostly mephisto genetics, so between 1-4 feet tall on what I grow, I saw some spiky leaves on full with reflectors so see how I go dimmed slightly

astonehead said:

How do you mean how long I want to grow them out? :/. I grow autos and mostly mephisto genetics, so between 1-4 feet tall on what I grow, I saw some spiky leaves on full with reflectors so see how I go dimmed slightly

Click to expand...

Oh ok, I didn't know you were growing autos. I was referring to how long you were planning on vegging them out.

Oh, yea autos for now atleast