BTU AC per 1000w cob?

Okay, all this relates to generation 6 of the Citi 1212C4 in 3000k/CRI80, but gen.5 is not far behind, maybe 2-3%.
It is best to name the exact order code next time from the beginning!
IMO, also with gen.5 you will match the 1500μMol/s/m² with your setup and I would not worry to much about the heat. The room itself is 49m²!!!, also if you only use 7m² for canopy. And if you use CO² your typical temps should be in the low 30°C anyways. Maybe you need only the dimmer or make a short summer break in the worst case if it's really to hot.

Randomblame said:

Okay, all this relates to generation 6 of the Citi 1212C4 in 3000k/CRI80, but gen.5 is not far behind, maybe 2-3%.
It is best to name the exact order code next time from the beginning!
IMO, also with gen.5 you will match the 1500μMol/s/m² with your setup and I would not worry to much about the heat. The room itself is 49m²!!!, also if you only use 7m² for canopy. And if you use CO² your typical temps should be in the low 30°C anyways. Maybe you need only the dimmer or make a short summer break in the worst case if it's really to hot.

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So you think I should run them at 6000w?

The room is 7m x 7m however it is a sloped roof like a loft room possibly only the 2m x 5m is over 230cm in hieght the rest is sloped so might not be as beneficial for heat dissipation

George2324 said:

45w per sq ft is without co2 tho right?

45w per square foot would be what ppfd?

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no i run low 30s without CO2

45w/SF at 50% efficiency would be around 1100 ppfd

George2324 said:

So you think I should run them at 6000w?

The room is 7m x 7m however it is a sloped roof like a loft room possibly only the 2m x 5m is over 230cm in hieght the rest is sloped so might not be as beneficial for heat dissipation

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Yes, under the roof can be problematic, but if you use dimmable drivers... Why not!?
1500μMol/s/m² and 1500ppm CO² is not even easy to handle but if you use a hydro system you should be able to supplement enough nutriens to keep them healthy. Only make sure you have always enough CalMag+ by hand at such intensity...

So if I can get a gram per watt with 1000w hps

What's the gram per watt like with led?

If I stick to 60w per sq ft at 50% efficiency then and hopefully that's will = 1500 ppfd

That would be only 4800w in total.

Could I expect to achieve 4800g from that space? I am a long term grower I'm not asking a what can I get question I'm asking what's is the rule of thumb like 1 g per watt hps... is it the same or 1.5g per watt of led?

Randomblame said:

Yes, under the roof can be problematic, but if you use dimmable drivers... Why not!?
1500μMol/s/m² and 1500ppm CO² is not even easy to handle but if you use a hydro system you should be able to supplement enough nutriens to keep them healthy. Only make sure you have always enough CalMag+ by hand at such intensity...

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Yeah I use hydro nutrients won't be an issue.

I have dimmer available hopefully I'll dial it in and get a par meter

Well, if you go to maximum yield per area, you will reap more with more light! But if you want max. g/w and the maximum yield is not so important, then you have to approach the thing differently!
1500μmol/s and 1500ppm will probably bring you to 1.25g/w...
If you want to reach 1.5g/w or more, you should only use 700-800μmol/s/m².
Consider the two screenshots below and you will see that the profits get smaller with increasing intensity.

Ah right I got you. I'll stick to the higher ppfd for more yield. I practically get paid to use my electricity here so electric bill isn't a problem.

Massive field of solar panels on my land I get paid for electricity I generate even if I use it.

1.2 gram per watt...
6000w over 7.2sqm
Would be 7200g in 7.2 sqm

That's 1 kilo per sq m... higher than every seed banks maximum yield I've ever seen... I'd love to see that

George2324 said:

Ah right I got you. I'll stick to the higher ppfd for more yield. I practically get paid to use my electricity here so electric bill isn't a problem.

Massive field of solar panels on my land I get paid for electricity I generate even if I use it.

1.2 gram per watt...
6000w over 7.2sqm
Would be 7200g in 7.2 sqm

That's 1 kilo per sq m... higher than every seed banks maximum yield I've ever seen... I'd love to see that

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Wishful thinking, that's maybe possible with a dialed in room +co2 enrichment & years of experience..............honestly I would lower the wattage, those stand up ac units you plan on using don't cut it on a efficiency standpoint and you might have issues in flower and lose the crop; big risk.

your money, your call, good luck

PSUAGRO. said:

Wishful thinking, that's maybe possible with a dialed in room +co2 enrichment & years of experience..............honestly I would lower the wattage, those stand up ac units you plan on using don't cut it on a efficiency standpoint and you might have issues in flower and lose the crop; big risk.

your money, your call, good luck

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What issues in flower are you talking about?

I've done several grows before. Plenty of experience and I've hit 1 gpw with hps plenty of times.

I'm just changing over to cobs.

I can get the portable ACs to remove 24000 BTU for 2600W. Not as good as a mini split but no other option in this case unfortunately

I use about 3kW in about half the size you are planning to use.
8" Extractor does a good job maintaining the sweet spot.
I have split AC, wall panel heater and ceiling fan too, but the extractor does 99% of the work.

ANC said:

I use about 3kW in about half the size you are planning to use.
8" Extractor does a good job maintaining the sweet spot.
I have split AC, wall panel heater and ceiling fan too, but the extractor does 99% of the work.

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3kw of cobs in 3.6sq m?

Do you know what your ppfd is?

3.5m x 4m with 42 COBs at 80W each
Sorry, no I have no measuring gear, it is CMX22s so it is quite efficient.
I thought they were veros, but my buddy who assembled them corrected me.

George2324 said:

What issues in flower are you talking about?

I've done several grows before. Plenty of experience and I've hit 1 gpw with hps plenty of times.

I'm just changing over to cobs.

I can get the portable ACs to remove 24000 BTU for 2600W. Not as good as a mini split but no other option in this case unfortunately

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You are going into winter and 24000 btu works for 4600k of cobs I know for sure I've flowered with a wall unit AC before and had to adjust the AC so the room wouldn't get too cold. Lets see what the others have to say about this pic of proof

^^^^ THIS^^^
Make sure to lift your pots off the ground or it will just sink all the heat from the rootball.
We were set back quite a bit of time after rooting the clones due to low temps.

REALSTYLES said:

You are going into winter and 24000 btu works for 4600k of cobs I know for sure I've flowered with a wall unit AC before and had to adjust the AC so the room wouldn't get too cold. Lets see what the others have to say about this pic of proof

View attachment 4024737

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Your cobs look like they are over a meter above your plants? I am planning to have mine around 12-15 inches away max.

ANC said:

^^^^ THIS^^^
Make sure to lift your pots off the ground or it will just sink all the heat from the rootball.
We were set back quite a bit of time after rooting the clones due to low temps.

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Really? Why is low temps bad for rooted plants? I don't see any clones in that pic.

Our clones rooted in small batches over a period of 2 or more weeks. So we had lots of different sized plants.
Cold temps at night also didn't help vigor any. Shit took really long to pick up speed. We are 46 out from harvest now.

George2324 said:

Your cobs look like they are over a meter above your plants? I am planning to have mine around 12-15 inches away max.

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No it's 18" it's just the way I took the pic. Here's a pic no AC 1800w in a 4' x 8' tent 56% efficiency stupid high PPFD and no CO2

George2324 said:

Your cobs look like they are over a meter above your plants? I am planning to have mine around 12-15 inches away max.

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Forget this! 12-15inch is way to less distance at such intensity and you will end up with getting massive bleaching. Get a cheap lux-meter and try to spread the light as much as possible for an even canopy coverage. Above 65.000lx(ca. 1.000μMol/s) it is really easy to get bleaching, also if you feed your plants with additional CO². Äquatorial sativas can handle intense light much better as a dutch outdoor indika for temperate climazones. So it's also strain dependent.

I would recommend to start with 24-30" and let the plants grow untill you see first signes of stress. Than rise the lamp a bit and keep that distance for the whole grow!