What’s good OG? First time poster, I still have gen1 eb 280mm, want to repurpose them, I need to light a 3 sq/ft space, can these 22.1v strips be ran by a meanwell xlg150 L ab series driver?
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Welcome to OG Kaneh_Bosm I expect someone will give you some good advice shortly, how many 280mm strips have you got?
Or the xlg-150-h you just need to run a series parallel array of two in series and as many groups of those that your running in parallel.
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Dang ChronicMcBuds, I can’t believe I missed your response! Sorry, I’m normally more observant.
Thanks. I’m definitely going to read up on this thread.
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I have 24, is that too many? I want to use asany as the driver allows
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Thanks @Mr.Sparkle and @Shadey I was about to buy a viparmarsspider joint 
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Ok, you have 3 sqr ft. Standard ‘rule of thumb’ is 30W (wall watts) per sqr ft.
Therefore you need 90 watts to satisfy the above.
I assume the part number for the strips is something like BXEB-L0280Z-40E1000-C-A3? (don’t worry about the last half) so they are 7.7 watts each.
90W/7.7W = 12 strips
Now the problem is the forward voltage for those strips is 22.1V. & your driver (xlg150 L ab) range is 142 to 431 VDC. This is a constant power driver, not constant current. Working with that range… 142/22 = 7 strips in a string and you would need 2 strings for a total of 14 strips .
This is not a ‘friendly’ driver… it can easily kill you if you mess up.
I’d suggest you look for a different driver. I would recommend the HLG series and I suggest looking at a higher than minimum size (like 2x)
HLG-185-H-24AB would be my pick.
Cheers
G
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Well curiosity got the better of me…
Cheap aliexpress 65w led panel, this one set me back $40cnd though had seen some as low as $28 shipped, i just preferred this layout pattern and went for a bit faster shipping.
Anyways had it on for literally 15secs before i was dismantling and desoldering power leads for power measurements as that was the whole reason i bought it i have no plan for this light i just wanted to see power and light measurements and how it compared.
Surprisingly it has right around 92% driver efficiency, 68w from the wall and 68.3V @ 0.916A to the board on initial fire up and 67.8v @ 0.897a and 66-67w from the wall after was running for awhile, though cheap build now don’t quote me on specifics as im just guessing here and may be off its likely utilizing a Full Wave Rectifier Bridge for the ac-dc conversion though it isn’t utilizing filtering capacitors or is quite ineffective as when using a camera im getting that classic AC zebra striping in any photo or video and it phases in and out right at 1/125 and 1/60 shutter speeds which makes sense with my 60hz wall ac frequency.
Construction quite cheap as expected… also doubly long tracer power lines with the way its laid out which isn’t needed though i understand the reasoning likely they aren’t using a smd chip placer that can rotate 180 degrees for polarity reasons or otherwise would need 7 feeders with half feeding in reverse to accomplish what a 4 feed system would with a rotating head, or however they are being placed.
As for light measurements those will follow as i have to move things or set something up or otherwise may just wait till my third cabinet is plant barren to do some tests vs say the bridgelux eb2’s that are in there on a xlg-50
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Anyone use stadium leds. Seen some low ass prices for 500w-800w lights in 3000k and 5000k just kinda wondering how they’d do in a grow room.
Well said. A hallmark of cheap when you can see it in the tooling, but not necessarily bad quality. Admire your work, man, keep it up.
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Thanks @Gpaw I have (2) 185h 24a drivers. I’ll put one to use.
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@EugeneDebs420 I think the big determining factor is their efficacy/efficiency and how easily they’re powered. Get some spec sheets on the 3000k and we can dig in to answer your question.
5000k is not worth the money unless you want to grow cabbage patch dwarf plants in veg. A redder spectrum with most modern LEDs is a lot better for speed of veg and vigor, and has no downsides with modern white LEDs because they contain so much blue light anyway, that the red does not encourage stretch.
Cheap isn’t usually better with LEDs. Don’t be penny wise and pound foolish. 
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I wouldn’t say that and would guess you haven’t flowered under 5000k or only done it once or twice as it can grow quite well, saying that it’s just a redder spectrum like 3000k is better at that energy wavelength to chloroplast conversion wise.
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I’ve flowered under both straight MH (in my own grows in the 90s and early 2000s) and 5000k blue LEDs (at a friend’s house) in the past. It can grow fine, but it’s not as good as a redder spectrum. It turns out that the latest research is showing the maximum amount of blue photons necessary for optimal photosynthesis and plant morphology in cannabis is somewhere between 3% and 10% of the total output. Anything above that becomes both electrically and monetarily inefficient for cannabis production. Yes, it will grow weed, but we need to stop steering people towards blue spectrum and actively warning them away from it when other options are available at the same price.
Speaking of the latest research, this KIS Organics Podcast with Bruce Bugbee has gone largely unnoticed by the cannabis community, but in it Bruce literally details all the latest research about cannabis lighting. The takeaways from this interview below are (in my personal order of importance):
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UV isn’t showing very good results for increasing terps or other cannabinoids after lots of lab testing compared to just blue photons. Blue photons might actually have bigger impacts, but neither are very important when you’re talking about optimizing total cannabinoid production compared to just more light. Which leads to the 2nd biggest takeaway, which is:
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Quantity of light is much more important than spectral quality to production of cannabis. Basically, when thinking about buying a light fixture, light output is by far the most important factor in your plants’ photosynthesis and production. Which leads to the 3rd big takeaway:
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When comparing light fixtures, the total ppf per dollar is probably the most important factor to consider. Spectrum is almost not even a consideration for Bruce, as long as it’s modern full spectrum white LEDs. And optimal spread is also super important because:
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Diffuse light is far better for penetration than direct light intensity. The greater your average ppfd across the canopy, the better your penetration. Eliminating shadows is the true measure of greatest penetration, despite all the manufacturers’ magic pixie dust claims.
Anyway, here’s the video:
And here are my notes of both what Bruce says here and what I’ve gleaned elsewhere from reading the latest research, by the rough timestamps in the video:
1:30 Bruce introduces what he does at Utah State University. Funded by NASA to research the effects of spectrum on higher plants - economic and agricultural crops (photobiology)
4:00 Bruce talks about his founding of Apogee Instruments in Logan, CO. They make instruments to measure light. Their tools help growers.
5:45 Bruce says Lux meters measure light pretty well, much better than your eyes which perceive light intensity very poorly, but lux meters weight the spectrum wrong, so they’re not accurate at telling you the intensity of each spectral color band. Noonday sun is about 200x more intense than typically well-lit office light (2000um/m2 vs. 10um/m2) and plants grow at almost 200x faster in under the noonday sun compared to office light. Takeaway: plant growth is almost linear with increasing light levels up to 2000um/m2. This is why we need light meters. Light intensity is the most important factor in plant growth.
9:00 Discussion of how Apogee sensors measure light - quantum sensors do intensity right with proper spectral weighting, but don’t tell you spectrum. For that, you need a spectral radiometer.
11:00 You need to measure light intensity because our eyes just can’t see it, even differences as small as 1 foot in any direction can look the same to our eyes, but might be radically different in actuality.
13:00 Quantity & Quality of light discussion. Bruce says that quantity is BY FAR the most important thing; quality is much less important. The daily light integral (DLI - # of photons per 24hr period) is the best predictor of growth - this is intensity usually measured in photosynthetic photon flux density (PPFD - amount of light in photons, per unit area, per time). Think of it like measuring rain per day. We try to not call it “light” in research because that term’s loaded with individual perceptions of quality. We call it photon flux for short.
16:00 The quality of light is the ratio of colors to each other, and it requires a spectral radiometer to measure accurately. Lower cost ones can’t discriminate colors from each other (cyan from blue, etc.) and this is important because can manipulate plant shape with the ratio of colors to each other.
18:00 Spectrum isn’t very important. Our eyes are good at telling colors apart much better than a plant. Plants don’t care very much about quality. Quantity determines plant growth. Quality impacts plant shape, but only to a small degree.
19:30 Spectrum Discussion - UV (below 400) is not bad. Some is good, both for humans and plants. UV exposure results in vitamin d in humans, and we thought it have a greater impact on flavor and smell in plants than it actually does. In the lab, manipulating UV wavelengths has had much less impact on terps and flavanoids than they expected, in both food crops and cannabis.
Blue is a big part of sunlight. It helps plants stay short and has a bigger effect on flavor compounds than UV.
Green photons are used by plants, very few bounce off plants, and they GREATLY help growers evaluate plant performance and diagnose plant health issues (pests, disease, deficiencies). Bruce says he’s a big proponent of putting MORE green into LED spectrum to help the humans, because it’s also really good for the plants (contrary to popular wisdom that because they’re green, green light doesn’t help them, which he notes is ALL WRONG).
Red photons are extremely efficiently used by plants (plants love them) and also easily & efficiently produced by LEDs, but red LEDs are expensive to produce by themselves, which is why we see blue LEDs with phosphor coatings to produce red spectrum. They are also very important for plant shape.
Far red are also extremely important, and have big effects on plants, increasing stem elongation (stretch), but they also provide a free lunch for photosynthesis - 2x photosynthesis for every 1 far red photon (only in the range of 700-750nm, tho) as long as there is enough blue to counteract the stretch side effects. It turns out only about 10% blue photon output from your light is needed to do this!
25:00 Green lights ARE NOT SAFE TO USE DURING DARK PERIODS OF FLOWERING CYCLES! Plants see green photons almost as well as blue and red, so no, it’s a myth that green lights are “Safe Lights” and plants won’t see them. If you have to go in at night, just use as dim of light as you possibly can. Be very careful about using any color of light at night. Again, light intensity is far more important than spectrum.
27:00 Bruce is researching cannabinoid synthesis FULL TIME in his lab, and specifically the impact of spectrum on cannabinoid content and ratios. They have NOT found nearly as much variation resulting from UV and blue photons as they expected to see. It’s not zero effect; it’s just a lot less than they expected.
28:00 Hash tips myth - they’re not caused by overall light intensity. There’s no evidence for hash tips being caused by either too high of an intensity of light NOR too much of a change from low light to high light. All the evidence in many many lab tests show that hash tips are caused by the ratio of red photons hitting buds in comparison to other colors, not the total intensity of all photons. Mfg’s put a lot of red in their LEDs, which is great for the plants and for the efficiency of the fixtures, but when the fraction of red photons exceeds about 70% of the total photons the plant seeds, in the lab they get hash tips (white bleaching of the parts of the plant receiving this much light). It’s just an absence of chlorophyll. It only happens when the fraction of red is super high, not when all photon intensity is super high. Bruce likens it to a buffet - plants love red photons, but they don’t elicit the plants making sunscreen to protect themselves from high intensity like blue photons do. So, the plant says, heck yes, we love red photons and we don’t have to protect ourselves against these!!! Thus the plants don’t produce natural sunscreen and the cholorophylls get broken down. This is non-intuitive.
32:00 Rapid changes of light intensity are not as detrimental to plants as we think. If you want to optimize production, Bruce says give them high light, don’t waste time and resources by ramping light. Don’t baby them. Why? Plants adjust to a change from super low light intensities to super high light intensities very quickly (usually in 1 day or less, always in a couple days at most). They’ve done tests where they take plants in 300ppfd and put them in 1200ppfd and the plants show an increased rate of growth of 4x almost always in 1 day or less with no detrimental effects. Plant chloroplasts will adjust their orientation from horizontal to vertical within minutes and certainly less than an hour when going from low light to high light, allowing photon penetration farther into a leaf tissue in high light situations. Thus, ramping lights up and down is useless over the lifespan of a light. However, there is a difference between leaf thickness. Sun leaves are much thicker, and plants will adapt so quickly that even if they don’t have many sun leaves, within 1 or 2 days of high light intensity they will start producing thicker leaves (long term).
36:00 DLI in flower is really important. Plants growth is regulated by DLI - the total amount of light they get in their light cycle. You want to increase light intensity in flower to make sure that DLI is at least the same, if not even slightly more, in flower.
38:00 Optimal DLI for cannabis production is usually considered as an economic optimum, and if talking ROI on the overall production facility, peak production from your floorspace under lighting (the area of your canopy) is maybe more important than just measuring efficiency by total watts consumed. You may be able to spend more on electricity and higher light levels to get more production.
Talking about metrics, grams/watt isn’t very good measure because optimal g/w production peaks at 5-600 umol, which is pretty low production but usually highly efficient and cheap to produce.
If you want to optimize your production facility from an economic perspective, you would measure in grams/watt/meter squared. When you put that area component into the calc you get a much better measure of production. Cannabis is a high light crop, and when you use g/w/m2 you get a peak productivity of somewhere between 1000-1200umol. Pushing it to 1600umol the yield continues to go up, but there’s a decreasing ROI the more above 1200umol you get. And there’s less margin for error, plus diminishing returns above that. Everything in the rootzone and external environment has to be optimal. Analogy: In high light you’re driving a racecar at 600mph. The tires, the brakes, the gas, the air intake all have to be optimal or you’re going to crash and burn. It takes a lot of engineering dollars and a huge pit crew to drive a racecar, but it only takes a little money and one of you to drive a Porsche 150mph. Still expensive and maybe dangerous, but a lot less dangerous and expensive overall.
41:30 CO2 enrichment is HUGE and it costs almost nothing. 1000ppm is optimal, 1200ppm is marginally better, above that is wasteful. More light = more watering and more nutrients. Make sure the plants don’t run out of water.
43:30 HPS vs. full spectrum LED in both veg and flower, or vice versa. 10 years ago everyone used MH for veg and HPS for flowering. Why? Because MH has lots of blue and kept plants short, but they’re not efficient electrically and cost more money to get high light levels. HPS is a near perfect spectrum Bruce says (4% blue, lots of green, lots of red), but LED are better because of efficiency, not because of spectrum. LEDs have a lot of blue - and you don’t want much, about 3-10% is the right amount of blue. 15, 20, 25% blue is not optimal for photosynthesis and may keep the plants too short.
47:30 660-680nm do not enhance anthocyanins (red pigments) which is photo protective pigments that protect against excess and UV light. These pigments actually block photosynthesis - red-leaf varieties grow slower than green leaf because the red pigments are blocking some of the light. It’s a price to pay for some pretty colors.
49:00 Evaluating commercial grow lights - what questions should we ask about lights?
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Budget - What’s the cost per watt of fixture?
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Efficacy - What’s the efficacy of the fixture (output divided by watts)?
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Beam spread - uniform canopy coverage from maximum number of point sources.
Lots of people still use HPS because they’re so cheap for the total output, but that’s short term capital considerations which may not be the best perspective. Total cost of ownership over the life of the fixture is more important for home growers and small commercial producers. If you’re talking about 2+ years of use per fixture, high quality LEDs become cheaper in almost all cases.
How much focusing of the light do we want? Focused light is great if you know where you want it, but optimal lighting is uniform lighting. LEDs are fantastic for this, and more uniform lighting is always better, all other things being equal.
53:00 White LEDs with reds are great, but the most cost effective LED is the one that produces the most ppf per dollar (with no more than 10% blue output).
54:30 The myths of “penetration.” What actually effects penetration? In the lab, they’ve shown that regardless of mfg claims or light technologies used, only two factors impact “penetration”:
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(to a lesser degree) Green photons penetrate deeper because some bounces off leaves and it penetrates thru leaves, so more gets below the top canopy.
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(to a much greater degree, that most people don’t often think about) The ratio of direct photons to diffuse photons. Diffuse photons are coming from all directions (cloudy day) and direct is like sun overhead with no clouds. Diffuse photons penetrate MUCH better than direct, so you want a very high diffuse photon to direct photon ratio. Thus, you will always be better with light fixtures that have a much broader beam spread coming from many more point sources. In a small grow, you will do better with the highest amount of point sources for the most diffuse lighting, such as fixtures with the highest amount of total diodes used. In a big open room, lots of HPS mounted at the top of the ceiling for greatest beam spread produce a similar effect, which is why big grows find HPS to be economically viable, despite low efficiency. What’s the tipping point for this? Probably the point at which the number of HPS achieves zero shadows in the middle of the plant. Color matters, but not as much as diffuse photons.
1:00:00 Pruning, especially excessive pruning of leaves, is a waste of time. They don’t prune in the labs, unless it’s necessary for air movement to prevent disease. Older leaves automatically move their resources to the top of the canopy. They translocate their stored nutrients to the top of the canopy where growth is occuring, naturally mobilizing their resources to where the plant needs them. If you take off the leaves, you’re removing nutrients and carbon that are free stored resources for the rest of the plant.
1:02:00 Lenses on LEDs are only good if they’re spreading the light to make it more diffuse. You don’t want to focus the beam; you want the opposite.
1:03:00 Spectral tuning has almost no benefits. Total intensity of photons is much more important than the spectrum. Again, more light per dollar is the most important factor in growing if you’re asking about what you should buy.
1:04:30 Active areas of cannabis research: UV studies are ongoing and are still understudied (but not as fruitful as they expected so far), and the minimum amount of blue light plants need is also an exciting area of research. Also light pollution during night cycles - how much light pollution can cannabis tolerate at night is an active area of research. They’re spending less time and research dollars in the future on spectrum variation because it hasn’t produced as good of results as they thought compared to the money it requires to control. Instead, the hot area of research is actually varying light intensity over the lifespan of a plant to optimize its growth rates.
1:06:45 Utah State extension is about to start an online class about The Science of Cannabis Cultivation. It will cost $950 but will be taught by Bruce and 3 other Utah State researchers and will include over 30 hours of lectures covering all areas of light and cultivation research specifically on cannabis.
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@nube Are you thinking about signing up?
And thank you for your notes!!
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Damn, I was looking into some new certificate classes in cannabis the have at UW Platteville but to learn from the man himself? Thanks for the heads up.
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Nah man, but it sounds like it could be helpful for commercial growers and hemp farmers. I hope the lecture recordings and class syllabus/notes make their way online for the public good. You know - our tax dollars at work! 
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Sheeeeeeet…@nube is going to be teaching some of those classes lol.
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lol no way! I’m just regurgitating what I’ve read.
The really cool thing about science is that it’s constantly being updated. There are very few things in science that are settled and considered “laws” - so few, you might argue nothing is settled; nothing’s set in stone as immutable fact. It’s all just our best (educated) guess right now, and I take heart that future generations of scientists will adjust and reinterpret those results, sometimes finding new and novel causes for even the simplest things. Conventional wisdom has a pretty short lifespan. Like Einstein’s long-standing theory of general relativity being called into question recently because new research shows it’s pretty far off when applied to new measurements of cosmic inflation and dark matter/energy.
For our purposes, it certainly doesn’t hurt that world-renowned plant biologists are finally starting to research this stuff, and we know their research is super legit and has to be rigorous and unbiased to get published in peer reviewed journals. Basically the exact opposite of bro science, academics are trustworthy because their whole reputations and futures depend on them doing good work the right way. They aren’t skewed by profit motives like the companies in the canna industry, and academics do better research in better facilities with better controls!
All that to say that we all stand on the backs of giants when we build the next generation of understanding. We always benefit when we regard current rigorous academic research as the gold standard stable foundation on which to build our perceptions and opinions. It makes sense to be mentally flexible enough to consider new information when adjusting our preferences and opinions. As they say, “The more you know…”
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That’s a lot of what teaching is. I could tell you rough concepts I’ve learned, but I couldn’t go into accurate detail to explain them as well as you do. I fly by intuition, and you’ve got fucking GPS.
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