LED help

ChiefRunningPhist said:

Ya, 30W/ft2 - 35W/ft2 for mid to high efficiency LED (2.35μmol/J - 2.7μmol/J), I'm not sure if you were asking for confirmation or not.


1m2 = 10.764ft2
1W = 1J/s


Lets say your LED pushes ~2.5μmol/J.

2.5μmol/J × (10.76ft2/m2) × [(30J/s)/ft2]
=
807μmol/s·m2



If your fixture is 2.1μmol/J, and your target PPFD is 850μmol/s·m2 then...

(850μmol/s·m2) = (2.1μmols/J) × (10.764ft2/m2) × [(θJ/s)/ft2]

(850μmol/s·m2) ÷ (22.604μmol·ft2/J·m2)
=
[(θJ/s)/ft2]

θJ/s = 37.6W

Walls ect will absorb some of the photons emitted, and if the spread or throw of your trajectory is greater than 1ft2, then youll have to add more wattage to achieve whatever per ft2 intensity you desire.


After further review of your light I'd estimate an efficiency of ~1.5μmol/J. The luminous efficacy of emission of a typical 5000k 80CRI SPD is somewhere around 310lm/W (max lumens per watt, or 100% efficiency). The datasheet linked shows a CRI of 67, so its luminous efficacy of emission is probably closer to 300lm/W (less diverse SPD, SPD is more clumped around base pump of ~450nm which is less observable to the human eye than a higher CRI SPD). The data sheet shows 98lm/W as the highest performing model in the 5000K category. A typical radiometric efficacy of the emission of a 5000K SPD is ~4.55μmol/J, perhaps a bit less considering lower CRI than the one I'm modeling after (a 80 CRI, max μmol/J or 100% efficiency).

View attachment 4471295

(98lm/W) ÷ (~300lm/W)
=
0.326 electrically efficient

0.326 × (~4.5μmol/J)
=
1.47μmol/J

So...


(416W) × (1.47μmol/J)
=
611.5μmol/s

You'd want to divide the surface area that the throw of your light creates by ~610μmol/s to calculate your canopy PPFD, at least concerning the street light. Lets say you hang it to the point that your throw is 4ft2.

(610μmol/s) ÷ (4ft2)
=
152.88μmol/s·ft2

10.764ft2 = 1m2 so...

(152.88μmol/s·ft2) × (10.76ft2/m2)
=
1644.98; 1,645μmol/s·m2; 1,645PPFD


That's quite a bit of blue light and not a very diverse SPD without supplementing with your clamp-on's. I'd recommend hanging the street light so that it provides a throw of ~12ft2 (548PPFD) and then add some 3000K 90CRI bulbs for the clamp-on's (enough for 300 - 350PPFD more, for a total of 850 - 900PPFD).
You can estimate your clamp ons in the same manner but use 340lm/W as the luminous efficacy of emission for a 3000k 90CRI bulb, and 4.8μmol/J as the radiometric efficacy of a 3000K 90CRI emmision. They won't be exact figures but will give you an idea of the wattage per bulb you'd want to buy/use, how many of them, and how high to hang in order to blend your ratio to your desired level.

Also you can buy a cheap light meter to estimate intensity or PPFD from. They are sensative to a limited spectra so they'll measure certain SPDs with more intensity than others and are not exact but they can give a, "this spot is brighter than this spot" type of indication. The measurements may resemble true intensity, or they may not, it just depends on the SPD of emission and the spectral response of the instrument. Price will likely scale with accuracy.

EDIT:
The calcs are averages, so you'll still have greater intensity directly under than at the edges, so if you're not reflecting the side emmisions back in you may want to further increase your hang height to account. If you're good with trig you can calculate an estimate based off the beam angle found on the data sheets, sometimes they're listed as radiance, or in units of output power per steradians per m2.

Click to expand...

fragileassassin said:

I tend to be the same way.
Best advice I wish i would have gotten. Unless someone can lay out data like chief just did, try to absorb a broad range of ways of doing things. Dont focus on one article or build and copy it directly, take aspects that would work for you and apply them in your grow and make it your own. In the end, it's a weed and if you take care of its basic needs you'll get an end result.
I've found that young plants love it really humid, but you need good air circulation as they start pushing out leaves. A few holes in the dome helps if you dont have any, but taking off for a few mins so they can get new air regularly works well for me.
Hydro can be difficult to get your feet wet with, it's often a save up and go big thing and a lot of ppl have difficulties.

Click to expand...

ChiefRunningPhist said:

Ya, 30W/ft2 - 35W/ft2 for mid to high efficiency LED (2.35μmol/J - 2.7μmol/J), I'm not sure if you were asking for confirmation or not.


1m2 = 10.764ft2
1W = 1J/s


Lets say your LED pushes ~2.5μmol/J.

2.5μmol/J × (10.76ft2/m2) × [(30J/s)/ft2]
=
807μmol/s·m2



If your fixture is 2.1μmol/J, and your target PPFD is 850μmol/s·m2 then...

(850μmol/s·m2) = (2.1μmols/J) × (10.764ft2/m2) × [(θJ/s)/ft2]

(850μmol/s·m2) ÷ (22.604μmol·ft2/J·m2)
=
[(θJ/s)/ft2]

θJ/s = 37.6W

Walls ect will absorb some of the photons emitted, and if the spread or throw of your trajectory is greater than 1ft2, then youll have to add more wattage to achieve whatever per ft2 intensity you desire.


After further review of your light I'd estimate an efficiency of ~1.5μmol/J. The luminous efficacy of emission of a typical 5000k 80CRI SPD is somewhere around 310lm/W (max lumens per watt, or 100% efficiency). The datasheet linked shows a CRI of 67, so its luminous efficacy of emission is probably closer to 300lm/W (less diverse SPD, SPD is more clumped around base pump of ~450nm which is less observable to the human eye than a higher CRI SPD). The data sheet shows 98lm/W as the highest performing model in the 5000K category. A typical radiometric efficacy of the emission of a 5000K SPD is ~4.55μmol/J, perhaps a bit less considering lower CRI than the one I'm modeling after (a 80 CRI, max μmol/J or 100% efficiency).

View attachment 4471295

(98lm/W) ÷ (~300lm/W)
=
0.326 electrically efficient

0.326 × (~4.5μmol/J)
=
1.47μmol/J

So...


(416W) × (1.47μmol/J)
=
611.5μmol/s

You'd want to divide the surface area that the throw of your light creates by ~610μmol/s to calculate your canopy PPFD, at least concerning the street light. Lets say you hang it to the point that your throw is 4ft2.

(610μmol/s) ÷ (4ft2)
=
152.88μmol/s·ft2

10.764ft2 = 1m2 so...

(152.88μmol/s·ft2) × (10.76ft2/m2)
=
1644.98; 1,645μmol/s·m2; 1,645PPFD


That's quite a bit of blue light and not a very diverse SPD without supplementing with your clamp-on's. I'd recommend hanging the street light so that it provides a throw of ~12ft2 (548PPFD) and then add some 3000K 90CRI bulbs for the clamp-on's (enough for 300 - 350PPFD more, for a total of 850 - 900PPFD).
You can estimate your clamp ons in the same manner but use 340lm/W as the luminous efficacy of emission for a 3000k 90CRI bulb, and 4.8μmol/J as the radiometric efficacy of a 3000K 90CRI emmision. They won't be exact figures but will give you an idea of the wattage per bulb you'd want to buy/use, how many of them, and how high to hang in order to blend your ratio to your desired level.

Also you can buy a cheap light meter to estimate intensity or PPFD from. They are sensative to a limited spectra so they'll measure certain SPDs with more intensity than others and are not exact but they can give a, "this spot is brighter than this spot" type of indication. The measurements may resemble true intensity, or they may not, it just depends on the SPD of emission and the spectral response of the instrument. Price will likely scale with accuracy.

EDIT:
The calcs are averages, so you'll still have greater intensity directly under than at the edges, so if you're not reflecting the side emmisions back in you may want to further increase your hang height to account. If you're good with trig you can calculate an estimate based off the beam angle found on the data sheets, sometimes they're listed as radiance, or in units of output power per steradians per m2.

Click to expand...

Rocket Soul said:

340 for luminous efficay rating on the 3000k 90cri?? Ive never calculated it myself but ive seen people quote 260-280.

Anyways lovely writeup, how goes your light?

Click to expand...

ChiefRunningPhist said:

@Texsun, @Rocket Soul, @Airwalker16

Yes you guys are correct. Apologies! Its quite a bit lower than 340lm/W! I was referencing a CRI80 and just estimated a small difference.. Smh. CRI90 3000K efficiency metrics of the LM301B emission look closer to ~300lm/W for luminous efficacy & for photonic efficacy, 4.94μmol/J

Attached are the .pdf's which can be zoomed in for a clearer pic ect, but here's a few screenshots for quick reference...

LM301B CRI80...
View attachment 4471934

LM301B CRI90...
View attachment 4471933

As far as the light, I think I've finally gotten over the hurdle of achieving good PFC in the PS. Hopefully have something soon. Will be working on it tonight (I've been getting sidetracked too much!).

Click to expand...

ChiefRunningPhist said:

@Texsun, @Rocket Soul, @Airwalker16

Yes you guys are correct. Apologies! Its quite a bit lower than 340lm/W! I was referencing a CRI80 and just estimated a small difference.. Smh. CRI90 3000K efficiency metrics of the LM301B emission look closer to ~300lm/W for luminous efficacy & for photonic efficacy, 4.94μmol/J

Attached are the .pdf's which can be zoomed in for a clearer pic ect, but here's a few screenshots for quick reference...

LM301B CRI80...
View attachment 4471934

LM301B CRI90...
View attachment 4471933

As far as the light, I think I've finally gotten over the hurdle of achieving good PFC in the PS. Hopefully have something soon. Will be working on it tonight (I've been getting sidetracked too much!).

Click to expand...

ChiefRunningPhist said:

5000K will work just fine. Buds will be smaller than majority red SPD. If you added some red your plants would like it. 3000K in the clamp lights and you're golden. Keep RH 45%+. After about 900PPFD you're just wasting electric. 416W + the clamp-on's is plenty for a couple plants in that space. Rule of thumb is ~30W/ft2 of mid to higher efficiency LED.

Click to expand...

ChiefRunningPhist said:

Ya, 30W/ft2 - 35W/ft2 for mid to high efficiency LED (2.35μmol/J - 2.7μmol/J), I'm not sure if you were asking for confirmation or not.


1m2 = 10.764ft2
1W = 1J/s


Lets say your LED pushes ~2.5μmol/J.

2.5μmol/J × (10.76ft2/m2) × [(30J/s)/ft2]
=
807μmol/s·m2



If your fixture is 2.1μmol/J, and your target PPFD is 850μmol/s·m2 then...

(850μmol/s·m2) = (2.1μmols/J) × (10.764ft2/m2) × [(θJ/s)/ft2]

(850μmol/s·m2) ÷ (22.604μmol·ft2/J·m2)
=
[(θJ/s)/ft2]

θJ/s = 37.6W

Walls ect will absorb some of the photons emitted, and if the spread or throw of your trajectory is greater than 1ft2, then youll have to add more wattage to achieve whatever per ft2 intensity you desire.


After further review of your light I'd estimate an efficiency of ~1.5μmol/J. The luminous efficacy of emission of a typical 5000k 80CRI SPD is somewhere around 310lm/W (max lumens per watt, or 100% efficiency). The datasheet linked shows a CRI of 67, so its luminous efficacy of emission is probably closer to 300lm/W (less diverse SPD, SPD is more clumped around base pump of ~450nm which is less observable to the human eye than a higher CRI SPD). The data sheet shows 98lm/W as the highest performing model in the 5000K category. A typical radiometric efficacy of the emission of a 5000K SPD is ~4.55μmol/J, perhaps a bit less considering lower CRI than the one I'm modeling after (a 80 CRI, max μmol/J or 100% efficiency).

View attachment 4471295

(98lm/W) ÷ (~300lm/W)
=
0.326 electrically efficient

0.326 × (~4.5μmol/J)
=
1.47μmol/J

So...


(416W) × (1.47μmol/J)
=
611.5μmol/s

You'd want to divide the surface area that the throw of your light creates by ~610μmol/s to calculate your canopy PPFD, at least concerning the street light. Lets say you hang it to the point that your throw is 4ft2.

(610μmol/s) ÷ (4ft2)
=
152.88μmol/s·ft2

10.764ft2 = 1m2 so...

(152.88μmol/s·ft2) × (10.76ft2/m2)
=
1644.98; 1,645μmol/s·m2; 1,645PPFD


That's quite a bit of blue light and not a very diverse SPD without supplementing with your clamp-on's. I'd recommend hanging the street light so that it provides a throw of ~12ft2 (548PPFD) and then add some 3000K 90CRI bulbs for the clamp-on's (enough for 300 - 350PPFD more, for a total of 850 - 900PPFD).
You can estimate your clamp ons in the same manner but use 340lm/W as the luminous efficacy of emission for a 3000k 90CRI bulb, and 4.8μmol/J as the radiometric efficacy of a 3000K 90CRI emmision. They won't be exact figures but will give you an idea of the wattage per bulb you'd want to buy/use, how many of them, and how high to hang in order to blend your ratio to your desired level.

Also you can buy a cheap light meter to estimate intensity or PPFD from. They are sensative to a limited spectra so they'll measure certain SPDs with more intensity than others and are not exact but they can give a, "this spot is brighter than this spot" type of indication. The measurements may resemble true intensity, or they may not, it just depends on the SPD of emission and the spectral response of the instrument. Price will likely scale with accuracy.

EDIT:
The calcs are averages, so you'll still have greater intensity directly under than at the edges, so if you're not reflecting the side emmisions back in you may want to further increase your hang height to account. If you're good with trig you can calculate an estimate based off the beam angle found on the data sheets, sometimes they're listed as radiance, or in units of output power per steradians per m2.

Click to expand...

Texsun said:

From what I’ve read, it’s all about the ph, tds, and ppm on water/nutes.

View attachment 4470909

Click to expand...

Texsun said:

Quick question.
Let’s say you add a reflective Mylar film (smooth or raised hexagonal domes, it matters, I know), but for simplicity reasons, not having a light meter, how do you value the adjustment factor if light height and footprint are ideal? Also, has anyone ever played around with different wall coverings to soak up any negative spectrums?

Click to expand...

Airwalker16 said:

White is the best reflective surface we've come up with. Unless in a tent, then the reflective material in them works just fine.

Click to expand...

Texsun said:

I experimented with an automotive windshield sun reflector. It was used, came out of my vehicle, to my knowledge it didn’t have anything toxic spilt on it. 24 hour experiment. Eighteen light, six dark. Lights on at six am, off at midnight. Visor was placed around plant, not touching, but in an order to reflect as much light as possible at the ninth hour of daylight. At the fourteenth hour, plant looks good, saturated with light. At the fifteenth hour, everything changed. Top growth was drooping, mature fan leaves turning almost a silver metallic color, top fan leaves clawing. Removed reflector, plant sat over night, and almost twenty four hours later, seems to be back to original state. Added twenty five ounces of straight tap water. Previously only r.o. bottle. All other parameters were held constant. Any ideas?

Click to expand...

Airwalker16 said:

Lol, that was your plant going to sleep man. Normally your lights are off so you don't notice or see it as much. But they're going to go to sleep whether it's dark in time or not.
[/QUOTE

I mus

Airwalker16 said:

Lol, that was your plant going to sleep man. Normally your lights are off so you don't notice or see it as much. But they're going to go to sleep whether it's dark in time or not.

Click to expand...

Yep, I completely fucked that comment up. I had been to hh, blame it on the booze.

Click to expand...

Texsun said:

i used “daylight” meaning my artificial light. Sorry for the confusion. So normally the lights would have been on. The plant didn’t do this until I reflected light back to it. Plant recovered after I stopped reflecting light.

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Texsun said:

What’s up guys? In my absence I’ve been a little busy. Acquired a new light from work, new freebie that a wind storm blew down. I have a new problem, any help will be reciprocated in electrical/automation help. Scratch my back, I’ll scratch yours. I need ventilation help. I can come up with a dozen ways that might work, or we could all sit around and watch a monkey fuck a football. I need to know what works. Will an in-line 4”-6” fan with carbon filter clean air/circulate the same air? View picks

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