Introducing CobKits.com - specializing in DIY and Citizen COBs

kaivorth

Active Member
Go with the citizen cobs. For the price you'll get much more bang for your buck
Initial price yes, efficiency no. Running at the low currents they need to be competitive with Cree, I don't want to sacrafice light penetration. 56% at 1400ma isn't bad at all.
 

CobKits

Well-Known Member
id take a higher number of fixtures for 'penetration' personally. even one additional 1212 would make up for the few percentage points in efficiency, for a chip that costs 1/3 as much

4000K:
1212 at 12", 1400 mA=451 PPFD
3590 at 12", 1400 mA=463 PPFD

3000K:
1212 at 12", 1400 mA=369 PPFD
3590 at 12", 1400 mA=391 PPFD
 

kaivorth

Active Member
id take a higher number of fixtures for 'penetration' personally. even one additional 1212 would make up for the few percentage points in efficiency, for a chip that costs 1/3 as much

4000K:
1212 at 12", 1400 mA=451 PPFD
3590 at 12", 1400 mA=463 PPFD

3000K:
1212 at 12", 1400 mA=369 PPFD
3590 at 12", 1400 mA=391 PPFD
Yes but that 1/3 as much will come back in electricity savings in just a couple grows I would imagine.

How do you calculate PPFD cause I'm doing something wrong apparently.
 

Abiqua

Well-Known Member
Yes but that 1/3 as much will come back in electricity savings in just a couple grows I would imagine.

How do you calculate PPFD cause I'm doing something wrong apparently.

ppf / m^2...
8 sq ft is roughly .79 of the meter.
 

CobKits

Well-Known Member
ppf = watts x QER i beleive
Yes but that 1/3 as much will come back in electricity savings in just a couple grows I would imagine.
possibly... if no other factors are limiting. youre talking a few percent in efficiency vs paying 3 times more for chips
 

kaivorth

Active Member
ppf = watts x QER i beleive




possibly... if no other factors are limiting. youre talking a few percent in efficiency vs paying 3 times more for chips
No different than buying a more expensive binned chip isn't it?

Price
4 Citizen 1212's $44
4 CXB3590's $120
Difference of $76

Efficiency
Citizen 45%
Cree 56%
Difference let's say 10%

If my bill from the LED setup is about $30, I'll save a measly $3 a month. A grow is roughly 4 months long?

I'll save $12 for every grow. I would need 6 grows before these break even.


Looks like you're right. Sorry, I just needed to see this in numbers. I'm back on board the Citizen train it looks like.

Where is the cheapest place for pre drilled & tapped Citizen CLU048 pin fin heatsinks?

Looking to run 6-8 of the 1212's at 1400ma now.
 

Abiqua

Well-Known Member
How do you calculate ppf?
umol/s ....I believe the spectrum has to be digitized to get this number? It isn't in any datasheet I am aware of...past umol/s for Various chips are posted somewheres....who will chime in...

@alesh...can you explain calculating PPF a little Further?

also
QER will give you PAR watts emitted but joules per umol is how to calculate umol/s.

Calculating PPF :)
PPF /nm = (10-3) * [λ Φ(λ)] / (Nahc),

where:

Na = Avogadro's constant, 6.022 x1023

h = Planck's constant (6.626 x 10-34 joule-seconds)

c = speed of light, 2.998 x 108 m/s

λ = wavelength in meters.

http://docs.agi32.com/AGi32/Content/adding_calculation_points/PPFD_Concepts.htm
 
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Abiqua

Well-Known Member
No different than buying a more expensive binned chip isn't it?

Price
4 Citizen 1212's $44
4 CXB3590's $120
Difference of $76

Efficiency
Citizen 45%
Cree 56%
Difference let's say 10%

If my bill from the LED setup is about $30, I'll save a measly $3 a month. A grow is roughly 4 months long?

I'll save $12 for every grow. I would need 6 grows before these break even.


Looks like you're right. Sorry, I just needed to see this in numbers. I'm back on board the Citizen train it looks like.

Where is the cheapest place for pre drilled & tapped Citizen CLU048 pin fin heatsinks?

Looking to run 6-8 of the 1212's at 1400ma now.
Which Cree Kelvin temp? 3, 35, 4?
 

kaivorth

Active Member
umol/s ....I believe the spectrum has to be digitized to get this number? It isn't in any datasheet I am aware of...past umol/s for Various chips are posted somewheres....who will chime in...

@alesh...can you explain calculating PPF a little Further?

also
QER will give you PAR watts emitted but joules per umol is how to calculate umol/s.

Calculating PPF :)
PPF /nm = (10-3) * [λ Φ(λ)] / (Nahc),

where:

Na = Avogadro's constant, 6.022 x1023

h = Planck's constant (6.626 x 10-34 joule-seconds)

c = speed of light, 2.998 x 108 m/s

λ = wavelength in meters.

http://docs.agi32.com/AGi32/Content/adding_calculation_points/PPFD_Concepts.htm
This shit just went way over my head LOL.

I'll give it another look in the morning. I appreciate how I'm depth you're going
 

Abiqua

Well-Known Member
So the joules per umol on the 3500k 80 cri is 4.65.

I have 3500K 3070's Cree CXB BB bins.....so lets use that example to calculate an example PPF....

1x 3500 @ 1050 mA = 36.45 Dissipated Watts the Qer is 324 so efficieny is 54.21% @ 175.66 L/watt [175.66/324 = 54.21]


PAR watts = 19.75
[36.45 Wdiss * 54.21%]
PPF = 91.8
[19.75 PAR w * 4.65 joules/umol for a 3500K Cree]




I believe this is the best all purpose temp?
whole nother "can o' worms" question. But a fine choice. I tend to think along the lines of strain dependency, but everyone has a different grow and response.

I run a perp setup with 4k, 35k and 3k to finish in the final weeks. I like the results across a wide variety. I want to try a year of 3500k and 2700k together, before I make anymore claims.
 

kaivorth

Active Member
So the joules per umol on the 3500k 80 cri is 4.65.

I have 3500K 3070's Cree CXB BB bins.....so lets use that example to calculate an example PPF....

1x 3500 @ 1050 mA = 36.45 Dissipated Watts the Qer is 324 so efficieny is 54.21% @ 175.66 L/watt [175.66/324 = 54.21]


PAR watts = 19.75
[36.45 Wdiss * 54.21%]
PPF = 91.8 [19.75 PAR w * 4.65 joules/umol for a 3500K Cree]





whole nother "can o' worms" question. But a fine choice. I tend to think along the lines of strain dependency, but everyone has a different grow and response.

I run a perp setup with 4k, 35k and 3k to finish in the final weeks. I like the results across a wide variety. I want to try a year of 3500k and 2700k together, before I make anymore claims.
Indica if it makes a difference. So much good info I'm getting today :)

Bedtime for me today. Hopefully this weekend I can put everything together and get a final price for the build and order. Bedtime now
 

HolyGhost23

Well-Known Member
cobkits.com. how much could would be for you to get me a 185-54. don't care on model so long as it does 54 volts and around 185 watts..

if you already answered this sorry.. this thread gets more posts than a live nude cam of amanda bines
 
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