Think ive been led astray

Michael Huntherz said:

2101 µmols at 422watts. Click the little arrow in the box around the quote to check it out, Bob.

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Wow, the sun at noon in summer is only 2000 PPFD. That's a lot of lumens too. Sounds like the ultimate grow light, if it's consistent over the whole area. Surely you cant be getting that over any great amount of area from only 422 watts though. Must just be under a certain spot, right? The XB-D high-bays get over 1700 18" below the light, but I know it drops way off as you move out from it. Or do you keep your lights close to the canopy? How far below the light are those readings from?

This article indicates that 1500 PPFD at 25-30 degrees C is the sweet spot for Cannabis cultivation. I wonder how many LEDs at what heght would be required to get that over a 4'x4' area. I'm sure it wouldn't be that intense to much depth but a SOG grow would work nicely, plants maybe 1 foot tall. I wonder how many watts that would require, maybe 1000-2000. The 400 watt high-bays would likely be good for a 2'x2' area, so 1800 watts including power supply draw.

ttystikk said:

Light decreases in intensity as the square of distance. That makes for round growing areas.

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I guess square spaces would be appropriate if you have a DIY lamp that spreads the LEDs out over the square area. With the commercial high-bays though, a round space makes the most sense to me since that's the shape of the beam. Otherwise you'd be trying to squeeze a round peg into a square hole.

BobCajun said:

Wow, the sun at noon in summer is only 2000 PPFD. That's a lot of lumens too. Sounds like the ultimate grow light, if it's consistent over the whole area. Surely you cant be getting that over any great amount of area from only 422 watts though. Must just be under a certain spot, right? The XB-D high-bays get over 1700 18" below the light, but I know it drops way off as you move out from it. Or do you keep your lights close to the canopy? How far below the light are those readings from?

This article indicates that 1500 PPFD at 25-30 degrees C is the sweet spot for Cannabis cultivation. I wonder how many LEDs at what heght would be required to get that over a 4'x4' area. I'm sure it wouldn't be that intense to much depth but a SOG grow would work nicely, plants maybe 1 foot tall. I wonder how many watts that would require, maybe 1000-2000. The 400 watt high-bays would likely be good for a 2'x2' area, so 1800 watts including power supply draw.

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372 Watts at 4 weeks, 4'x4' starting with 3-5" clones. The intensity is intense, yo. I don't have the numbers, sorry. @REALSTYLES does. This is not the panel I referred to in my last post, but the previous design. Dude has it going on, in my opinion. As I understand it you're looking at 16 CXB3590s per 4'x4' running at roughly half power. No A/C required, just a big computer fan on each heatsink.

That does look good. They're not even right down close to the canopies, but it's only veg stage. Still, I'm doubting that 372 watts is going to provide 1500 PPFD all over. I need to see meter readings. I guess you could get decent growth even with less than 1500. The graph shows that it actually starts giving diminishing returns after 1000. Looks like only about 10% more photosynthesis going from 1000 to 1500. In fact it looks like only about 25% increase from 500 to 1000. For practicallity I guess somewhere between 500 and1000 should be a realistic goal. You wouldn't really be getting a good return on power input over that. It's not easy to get even a consistent 500 over an entire 4x4 area though, from the footprints I've seen from most comercial lights.

For instance, this shows that a Spectrum King only lights a 2 foot square with an average of maybe 400 PPFD at 36". That's why I estimated about 1800 watts for a 4x4 area. Though maybe the same number of LEDs closer to the area and spread out evenly over it would do better. Actually, it looks like the SK would be best for probably an 18" circle. With the sides reflectorized with mylar it should be usable. So essentially one medium plant per light. Maybe a 2 foot circle with short SOG plants.

One of these 20 gallon trash cans would probably work. Just put some holes around the bottom part and also the top part. Heat would pull air up through it for ventilation. Mount the light in the middle of the lid so the fins are outside. You got a nice little grow unit. Maybe two of the cans stuck togeter, the top one upside down, for one larger plant. The light mounted in the bottom of the top one. Guess you'd have to cut an access hole in the side of the bottom one for watering. Put hinges and a handle on it. Or maybe just one upside down can placed over plants in pots on the floor. Anyway, it has potential. Just gotta find the best way of setting it up. Those cans are cheaper than grow tents and the white should reflect light nicely.

BobCajun said:

That does look good. They're not even right down close to the canopies, but it's only veg stage. Still, I'm doubting that 372 watts is going to provide 1500 PPFD all over. I need to see meter readings. I guess you could get decent growth even with less than 1500. The graph shows that it actually starts giving diminishing returns after 1000. Looks like only about 10% more photosynthesis going from 1000 to 15000. In fact it looks like only about 25% increase from 500 to 1000. For practicallity I guess somewhere between 500 and1000 should be a realistic goal. You wouldn't really be getting a good return on power input over that.

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Watch that guy's youtube videos, he'll be posting more as flower progresses, and some of the older light panel builds have impressive results. There are a number of people pulling >1g/W from their COB grows.

Michael Huntherz said:

Watch that guy's youtube videos, he'll be posting more as flower progresses, and some of the older light panel builds have impressive results. There are a number of people pulling >1g/W from their COB grows.

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Yeah I'll subscribe and view his other vids. Thanks for the tip.

There are many guys here that are long time users of LEDs and getting way more than 1 GPW with the newest generations of LED's. It wasn't that long ago that realstyles was arguing against high end LED's and now he's suddenly the poster child for their use,doesn't make any sense to me but whatever.

captainmorgan said:

There are many guys here that are long time users of LEDs and getting way more than 1 GPW with the newest generations of LED's. It wasn't that long ago that realstyles was arguing against high end LED's and now he's suddenly the poster child for their use,doesn't make any sense to me but whatever.

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Well hey, you gotta learn somehow, right? I usually fight a new idea at least once before I let it through the door, myself.

alesh said:

Well, you can. The trick is to use large COBs at really low current. You can get about 220lm/W from the top bin CXB3590 at 23W. And there's a few more 200lm/W options.

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Cool, so to get 5000 lumens efficiently you have to spend $88-$114 just for the COB (CD & BD bins Mouser) let alone the heat sink and the driver. Even if you went the cheaper route and got the lower bins from KingBrite, you still have a hefty investment to make for a high efficiency panel using CXB3590's.

Michael Huntherz said:

2101 µmols at 422watts. Click the little arrow in the box around the quote to check it out, Bob.

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That is an impressive panel but how much did that cost to make?? Just guessing by 8 CXB3590's along with heat sinks, drivers and optics, that there is close to $800 (at least) in parts in that light. How much would a light like that retail for if it was wrapped in a "commercial" fixture?
Also, I don't see that panel covering a 4x4.. evenly anyways..

On a side note, since there is a lot of talk about the XB-D chips not being that great, I did some more research in the "Binning and Labeling" Doc. on Cree's website . While there are certainly more efficient options, the higher bin XB-D's (group code Q4-R2) can put out up to 112 Lumens/Watt at a Tj of 85 degrees C @ 350 ma according to the Cree Product Characterization Tool. If you are able to lower the Tj to 50 degrees C you gain about 5-6% in output meaning 118 Lumens/Watt in THEORY. Not too bad. Now please remember that this is for one individual diode. In a spot light type fixture, these diodes would be packed in as tightly as temps would allow. Now the crossover light from each diode will greatly exponentiate the output of the "luminaire" as a whole, even if the individual diode performance doesn't blow minds. If a whole bunch of these were grouped together and the Tj was kept fairly low, I could see the output being pretty impressive for watts consumed. Especially with an efficient reflector.

cdgmoney250 said:

Cool, so to get 5000 lumens efficiently you have to spend $88-$114 just for the COB (CD & BD bins Mouser) let alone the heat sink and the driver. Even if you went the cheaper route and got the lower bins from KingBrite, you still have a hefty investment to make for a high efficiency panel using CXB3590's.


That is an impressive panel but how much did that cost to make?? Just guessing by 8 CXB3590's along with heat sinks, drivers and optics, that there is close to $800 (at least) in parts in that light. How much would a light like that retail for if it was wrapped in a "commercial" fixture?
Also, I don't see that panel covering a 4x4.. evenly anyways..

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You could design a panel that covered 4x4 by itself I suppose, but that one is intended to cover 2x4, more or less. Yes, you will spend $700-$800 per panel right now, so $1500+ for a commercial fixture, if someone were to start selling them. Sofa King What? No more A/C for the tent, easy maintenance, long life, incredible grams per watt yield and electrical efficiency are going to come at a cost. That cost is rapidly dropping and the quality of available COB arrays is rapidly rising. Some of these panels running under 400 Watts already crush a 600W HPS, from what I've seen, and I'll bet that a year from now the evidence will be overwhelming these COBs arrays are the way to go to grow, hi ho, hi ho, yo-yo oh no. I'm high as fuck.

Have you guys seen growmau5's YouTube channel? He got over 1.5 grams per watt of primo bud, 1.83 grams including the lowers. From a 285 watt rig he got 521 grams.

Michael Huntherz said:

You could design a panel that covered 4x4 by itself I suppose, but that one is intended to cover 2x4, more or less. Yes, you will spend $700-$800 per panel right now, so $1500+ for a commercial fixture, if someone were to start selling them. Sofa King What? No more A/C for the tent, easy maintenance, long life, incredible grams per watt yield and electrical efficiency are going to come at a cost. That cost is rapidly dropping and the quality of available COB arrays is rapidly rising. Some of these panels running under 400 Watts already crush a 600W HPS, from what I've seen, and I'll bet that a year from now the evidence will be overwhelming these COBs arrays are the way to go to grow, hi ho, hi ho, yo-yo oh no. I'm high as fuck.

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So $800 to cover a 2x4 square when you literally have to make the light yourself?? And that is just for parts. If someone started to sell these "64% efficient " fixtures to cover a 4x4 space it would cost approximately $1500-$1600 just in parts. So assuming you didn't do work for free, or sell products with 0% profit margin..... (Taking into account REALSTYLES light) if someone made a fixture like that to cover a 4x4 area, and that product had a 35% profit margin... It would cost about $2000 Retail before tax.
Sure it would blow most products you can buy commercially out of the water.. But at a substantial initial investment of money.

I have nothing against COB's WHATSOEVER. I think they are awesome and perform way better than HPS. That is why I use them.

But if someone wants to make a fixture that lights up a 4x4 adequately and is charging $1200, I would think it to be worth considering. Not everybody wants to DIY or spend $2k to light up a 4x4 tent.

I doubt you could sell many lights really, due to a glut of other companies and because once somebody buys one they don't need to buy a replacement for 10 years. It might make money but probably wouldn't be worth the trouble and risk to do it as a business. I don't think the Spectrum King guy is making much money or he wouldn't be going to trade shows and stuff. This seems like something you just do for yourself.

I am(/was) in the market for an LED and after watching many SK videos and considering buying them, I came across a @Growmau5 video that opened my eyes to the world of DIY LED. I figured I can either spend $1000ish on someone else to build my lights with unknown internals(and unbelievable claims like SK) or build a light and have full control over parts and spectrum, easy choice for me. Thanks SK!

cdgmoney250 said:

So $800 to cover a 2x4 square when you literally have to make the light yourself?? And that is just for parts. If someone started to sell these "64% efficient " fixtures to cover a 4x4 space it would cost approximately $1500-$1600 just in parts. So assuming you didn't do work for free, or sell products with 0% profit margin..... (Taking into account REALSTYLES light) if someone made a fixture like that to cover a 4x4 area, and that product had a 35% profit margin... It would cost about $2000 Retail before tax.
Sure it would blow most products you can buy commercially out of the water.. But at a substantial initial investment of money.

I have nothing against COB's WHATSOEVER. I think they are awesome and perform way better than HPS. That is why I use them.

But if someone wants to make a fixture that lights up a 4x4 adequately and is charging $1200, I would think it to be worth considering. Not everybody wants to DIY or spend $2k to light up a 4x4 tent.

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I hear you loud and clear, I agree once the pricing gets into that range then commercially produced units will be viable. $1200 is still a lot of cheddar to cover a 4x4, but you are eliminating a lot of complexity in terms of heat management, and pulling some fuckin' fire with 1/3 less wattage. That sounds pretty attractive at that price, I concur, my fine fellow.

cdgmoney250 said:

Cool, so to get 5000 lumens efficiently you have to spend $88-$114 just for the COB (CD & BD bins Mouser) let alone the heat sink and the driver. Even if you went the cheaper route and got the lower bins from KingBrite, you still have a hefty investment to make for a high efficiency panel using CXB3590's.


That is an impressive panel but how much did that cost to make?? Just guessing by 8 CXB3590's along with heat sinks, drivers and optics, that there is close to $800 (at least) in parts in that light. How much would a light like that retail for if it was wrapped in a "commercial" fixture?
Also, I don't see that panel covering a 4x4.. evenly anyways..

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Never said it's cheap. But you can have 3500K CDs for $48 from KB. About $60 on the driver and about $100 for HS and the rest. $550 for 200W 2.9µmol/J (the closest competition is somewhere around 2-2.1µmol/J). Performance somewhere between a 400W and a 600W HPS.

Parts for the commercial fixture would about as expensive as parts for DIY. But you have to count tools, machining costs, testing, certifications, employees (...) and profit. I can see a price in $1000-1200 range.

Right now the best commercial grow light would probably be the Cree Edge flloodlight/area light series. They're flat, about 4 inches thick, wide and square, about 2.5 feet each way. No fan required. A litte heavy at 45 lbs but not too bad. You can get them in 700 and 1000 ma currents and dimmable. They're currently a little pricey retail, about $1500-2000 depending on wattage, which you can get up to 1000. As a business, I would just get them in bulk and rebrand them as "Power King" grow lights, or something like that. Save yourself a lot of screwing around.

BobCajun said:

Right now the best commercial grow light would probably be the Cree Edge flloodlight/area light series. They're flat, about 4 inches thick, wide and square, about 2.5 feet each way. No fan required. A litte heavy at 45 lbs but not too bad. You can get them in 700 and 1000 ma currents and dimmable. They're currently a little pricey retail, about $1500-2000 depending on wattage, which you can get up to 1000. As a business, I would just get them in bulk and rebrand them as "Power King" grow lights, or something like that. Save yourself a lot of screwing around.

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Nice find, I'm intrigued by this, anyone want to donate $2k to my unscientific science experiment growing with one of those? I bet they work quite well. I only need $1500 for the one I want, but my time is worth something!

http://synergylighting.us/led-lighting/led-retrofit/led-high-low-bay/cree-hby-eho-70-dm-12-e-421w-421-watt-edge-series-high-output-high-bay-light-fixture.html

Michael Huntherz said:

Nice find, I'm intrigued by this, anyone want to donate $2k to my unscientific science experiment growing with one of those? I bet they work quite well.

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You don't have 2k laying around? What are you doing wrong with your grow? BTW, you can get them with different light spreads. You need to choose the appropriate ones.