Citizen grow

abaloneandbuds

abaloneandbuds

Active Member
Hey dudes, thought I'd share what I'm doing as I promised...

in the middle of a build, ladies show up in two days. pics show where I am now.

est 650 ppfd, planning cyclical CO2, AC @ 80F, and Grand daddy Purp for the first round.






Running 70 CLU-048-1212 80 CRI 3500K, total wattage ~3500W. tent is nominally 5'x10'. lights are set at 4x8.

All input welcome.
 
abaloneandbuds

abaloneandbuds

Active Member
Well, I'm mistaken, as was pointed out in another thread, and I forgot the µmol/j multiplier. I have to rethink my grow space into something about twice the size.

For anyone reading this and sizing their grow:
Watts*QER/m2=PPFD. QER being in the units of µmol/j. leaving out this multiplier makes a big difference.
 
abaloneandbuds

abaloneandbuds

Active Member
Let's test that theory.
3600w×2.67/3m2= 3200 ppfd. This is also 112 w/m2, which is about double the max recommended. Half of that density, 1600 ppfd, is high but functional. I can't see 4.8 being accurate without a missing multiplier of 0.5 or so.
 
DonBrennon

DonBrennon

Well-Known Member
Wow, that's a lot of light for that tent, it'll also produce a shit load of heat, I reckon you could double your footprint
 
Rocket Soul

Rocket Soul

Well-Known Member
This thread would be a good place to start figuring out the math: https://www.rollitup.org/t/math-behind.868988/

QER is not something that is relative to a specific chip, its relative to its spectrum: 3500k 80cri, and wil vary slightly between manufacturers but generally not between diffrent chips of the same brand.

2.67 sounds wrong on the top of my head, normally the led cobs have a qer between 4 and 5. 2.67 could be ppf/watt for a specific light configuration, including efficiency etc. Sounds high as most top fixtures top out at 2.4ish.

For calculating coverage count 15-20 par watts (total watts * efficiency) per square foot. Rough estimate you have enough to cover twice as much as intented. Happy growing and merry xmas
 
abaloneandbuds

abaloneandbuds

Active Member
3600 × 4.81/ 6.5m2 = 2660 ppfd. Damn.

If I go to 10×10, that's basically 9m2, and I get 1925 ppfd.

Going to the size of the entire room in working with... 13.25m2 I get to a more reasonable 1300 ppfd.

Guess I have some building to do
 
abaloneandbuds

abaloneandbuds

Active Member
Rocket Soul said:
Sounds high as most top fixtures top out at 2.4ish.

For calculating coverage count 15-20 par watts (total watts * efficiency) per square foot. Rough estimate you have enough to cover twice as much as intented. Happy growing and merry xmas
Click to expand...
OK so there is an efficiency that is tagged in there. I'll look at that link, thanks.

Edit: huge thanks for the link. My calculus is rusty at best, but I got the gist of spectral power distribution and how to get micromoles per joule out.

So, it's 4.81 micromoles per joule, but that's in terms of the joules that are emitted as photons. After we take into account electrical efficiency, we're knocked down into the 2.4 range previously discussed.

Nonetheless, my tent is too small, but my room is not.

Anyone have a link to electrical efficiency data on the citizens? (Paging cobkits lol)

Until then, assuming roughly 50%, that knocks my 13m2 room to my original goal of ~650 ppfd. I will have to do something to spread my cobs out though.
 
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DrBlaze

DrBlaze

Well-Known Member
So you bought 48v drivers? Those are 36v cobs. Those drivers have adjustable voltage, but only go down to about 43v, so they'll burn out those cobs as soon as they're powered up.
 
abaloneandbuds

abaloneandbuds

Active Member
DrBlaze said:
So you bought 48v drivers? Those are 36v cobs. Those drivers have adjustable voltage, but only go down to about 43v, so they'll burn out those cobs as soon as they're powered up.
Click to expand...
By running multiple cobs in parallel I should avoid that because the drivers will be switching to limit current.

If that's wrong, I can put the small leds in series to get the voltage I need.

I have run the cobs about an hour now though

Edit: spec sheet shows constant current operation from 24-48v.
 
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DrBlaze

DrBlaze

Well-Known Member
I don't think you grasp how these things work.

Constant Current drivers are hooked up in series with the cobs.

Constant Voltage drivers are hooked up in parallel with the cobs.

The driver you show in the picture is a Constant Voltage driver. How hard your cobs are driven when it is undimmed is calculated by how many cobs you have hooked to it in parallel. Every cob you add to the run reduces the wattage to each and increases the efficiency of all of them.

Here is the spec sheet of the HLG-185H-48A:

Clipboard01.jpg


As you can see, there is a small voltage adjustment (43v-53v), but that is just to limit voltage to a certain maximum, so that if a cob or more drops, you won't get a surge in voltage to the other cobs.

The dimming with these drivers is done by reducing the amperage.

I can only assume that you have been mistakenly looking at the spec sheet for a Constant Current driver..

If you had posted this thread in the proper area (Led and other lighting) this would have been caught by others sooner.

@CobKits ^^^^^^
 
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abaloneandbuds

abaloneandbuds

Active Member
DrBlaze said:
I don't think you grasp how these things work.

Constant Current drivers are hooked up in series with the cobs.

Constant Voltage drivers are hooked up in parallel with the cobs.

The driver you show in the picture is a Constant Voltage driver. How hard your cobs are driven when it is undimmed is calculated by how many cobs you have hooked to it in parallel. Every cob you add to the run reduces the wattage to each and increases the efficiency of all of them.

Here is the spec sheet of the HLG-185H-48A:

View attachment 3860939


As you can see, there is a small voltage adjustment (43v-53v), but that is just to limit voltage to a certain maximum, so that if a cob or more drops, you won't get a surge in voltage to the other cobs.

The dimming with these drivers is done by reducing the amperage.

I can only assume that you have been mistakenly looking at the spec sheet for a Constant Current driver..
Click to expand...
I have a different spec sheet with the same label on the top
 

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