Actually this is probably the best place to post this, cant remember if I already asked this question but here goes… Is anyone aware of any 18 volt or 36 volt LED strips with a maximum length of 560mm that have any combination of the following LEDs:
Deep Red
Infra Red
Ultra Violet
I am hoping to add to an existing 36 volt build. Preferably without any voltage stepping.
UV and IR have no proven benefit, only theorized. IR is of no practical value in high-temp LED grows that we know of…yet. UV may do something, but UV diodes are terrible and expensive and short-lived. And it’s theorized that near-UV excites the same pathways as UV might do (such as the blue spike in all white LEDs due to what @Mr.Sparkle noted about the coating that makes mixing CCTs of no value with modern white LEDs). There’s literally only one UV study that people hang their hat on, done in 1987 with questionable methodology and crude controls, and it’s never been repeated.
Bridgelux 2700k 90cri strips have a lot of deep red and especially far red which, as @ReikoX pointed out, creates an Emerson Effect.
You’d be better off just getting the 90cri 2700k EB3 strips which fit your voltage requirements, and are cheap, rather than spending money on short-lived diodes of questionable value.
But hey, it’s your money. 
What’s it they say about certain people and money?
I suggest watching these videos by PhD researchers studying this shit and reading the actual peer-reviewed papers produced by Bugbee and others on the subject:
and then this one:
and, lastly, this one with three PhDs, two of whom own lighting companies, talking about the nearly complete lack of proven benefit of supplementing spectrum other than far red’s Emerson Effect:
@nube. For sure. I have watched a couple of those already. I was not aware of the Bridgelux producing good deep and far red. That would be a perfect solution. Thanks for the tip, I have some research to do
I have had a setup here with 2 tents. One is organic super soil with cool and warm white LEDs and some deep and far red. The other is a DWC with Solstrips with no deep or far red additions. Both tents run the same strain from the same mother in all grows. The organic tent with deep and far red would start to flower after 1 week from flip with a stretch of 2x while the DWC would take 2 weeks from flip with a stretch of 3x. I then took a small deep and far red LED and on the following grow added that to the DWC tent during the first 3 weeks from flip to 12/12. That time the DWC tent started to flower after 10 days from flip and stretch was 2.5x.
I am not convinced but this is definitely enough to make me want to investigate further.
Thanks for the tip, kind of makes sense to shoot for the warmer range in 2700K if they’re already going to have blue in them… I might still mix in a small amount of maybe 5k so it doesn’t get too stretchy?
where are you all buying your DIY led stuff? I looked and it cost more for me to build then to buy it.
No big deal. I recommend reviewing them again because they’re very instructive on this subject.
I’ve posted it before in this thread, but here’s the goniosphere analysis of Bridgelux EB3 2700k 90cri strips at close to nominal current:
I would say get the most efficiently-produced photons you can for your money from this type of white, midpower LED anywhere in the range of 3000k - 4000k for veg & flowering, 2700k - 3500k 90cri for flowering.
It doesn’t have to be Bridgelux, but their strips represent the most photons for the money and nearly the most efficient. And it’s not even close. Samsung and boutique brands are quite a bit more expensive or they have diodes placed too closely to give you an even spread. Or they run too hard so you need expensive and heavy heatsinks.
Don’t spend money on supplementing or doing anything exotic - there’s just no proven benefit outside of FR and you only need a little of that. (Luckily there’s lots of FR in the Bridgelux 90cri strips!) And as in the case of UV, a lot of possible danger to both you and the plants. You’re better off just getting better at growing. Save your money instead of chasing a theoretical 1% gain for 20% extra cost. I mean that generally, not you specifically.
As for mixing CCTs, again, there’s really no benefit to adding 5000k. In a production setting, you want the fastest growth you can within the morphological parameters you define (essentially, with the shape you want). Scientifically, red and far red photons make for the fastest and biggest growth. If you have a very small space and don’t want big plants, sure go with more blue in veg. But, if you have no serious restrictions, there’s no point to add blue in veg against a typical 3000k or 3500k spectrum from Bridgelux or Samsung. But do remember that the CCT does not equate to a particular spectral distribution.
The reason why people wanted to veg with metal halide (fair amount of blue but also lots of green and yellow photons) in the past was because the only other option was HPS, which was almost exclusively yellow/red photons. If you have only yellow/red photons, without any blue to temper them, you end up with fast growing but viney plants. That’s as undesirable as going with mostly blue which ends up with tiny, no stalk cabbage patch plants. 
Modern white LEDs in the range of 3000k - 4000k contain mostly green/yellow/red photons with varying proportions of blue (more blue the higher the color temp). But you don’t need very much blue to keep the vining response from the red in check. Hardly any at all. For sure no more than 20% no matter what cultivar, but typically 10-15% photons in the range of 380-500nm is fine.
Blue photons make plant cells grow smaller and slower. In general, we’re pretty sure most cultivars like a little more blue in veg because it results in smaller cells which means hardier stems which is good outside in unpredictable wind conditions, but almost any spectrum will grow your plants in veg. Flowering does slightly better with more red and far red mixed into a broad spectrum white. Terps and cannabinoid content being impacted by spectral distribution is only theorized, but very few action mechanisms are hypothesized and none of it is proven at this point (not even UV).
And, lastly, it’s currently theorized that cannabis stretch in veg is largely due to spectrum. However, as the theory goes, stretch after flip is mostly genetic and happens (largely or completely) independent of light spectrum. This isn’t proven, but they think stretch after flip is mostly due to genetic factors and Daily Light Interval (DLI - how many photons the plant receives per 24hr period). The shape and weight after stretch, however, is dependent upon spectrum (all other variables being held constant).
@Who Digikey, Futureelectronics for the strips, and lots of places for the drivers and wire and extras. Octopart.com has a great part number search, so search here for builds that list the parts, then search those places for the part numbers.
Hope that helps!
So one thing I’ve noticed looking a lil closer at the EB special is that the CRI 80s have a better typical efficacy than the CRI 90s…
I thought I also heard that the higher the CRI the better as it is that much closer to actual sun light…
So which is better to go with?
Also, am seeing that lower than 4000k also has lower efficacy…
Man this is confusing lol
I was leaning towards the 2700k and maybe a 5000k or even 5700k in like maybe 3:1 ratio but now maybe just the 4000k sounds best?
Still no idea lol
Thanks @nube, @Mr.Sparkle, @Gpaw for re-post, I didn’t see this above… must have dosed off and missed it.
This definitely got me over the hump. Much appreciated!!
Thanks @nube, going through all your answers to other posters questions too. Some good stuff. Saving peoples pockets
Two main things to consider when looking at LEDs in the same layout and general density. Efficiency and efficacy.
LED electrical efficiency is essentially how many photons total are produced by each joule (or watt) of energy. This is umol/j spec you see being thrown around. Some measure the diode in a theoretical situation (most efficient measurement results, but least real-world), some measure the board/PCB with all diodes as a whole but leave out wall and driver losses, and some measure the whole lighting system in situ (least efficient measurement results, but most real-world applicable).
Efficacy means (roughly) how good the photons are at driving photosynthesis. Blue is electrically efficient but not super efficacious, which is why you see higher CCT showing higher umol/j or lumen/watt figures. Red is slightly lower efficiency since they just take blue diodes and put a phosphor coating to make the lower color temps, but red photons are more efficacious at producing plant cell growth and expansion. Each have impacts on the shape of most cultivars in both veg and in flower after flip - blue shorter plants with woodier stems, red bigger plants that grow faster and have less robust stems - however you will always find certain outlier cuts/phenos
80cri also generally have higher efficiency but, depending on the ratio of the colors to each other, it may not be more efficacious. And that’s the tradeoff, in simplified terms, of running slightly lower efficiency to get slightly more efficacy. Again though, the CCT (color temps) doesn’t define the spectral distribution, so 3000k 80cri in Samsung strips is not the same spectral distribution as 3000k 80cri in Bridgelux.
For instance, for flowering there are diodes and/or strips that are more efficient than the Blux eb3 2700k 90cri (such as the Samsung LM301B or H - same diode, different bins & part #s for different applications), but you can’t get them in 2700k or 90cri, both of which in the Bridgelux lines add a lot of photons in the red to far red range. And that extra red and far red helps in flowering.
The last thing CRI does for you is help your eye see truer colors. This benefits plant issues diagnosis and pest ID, as well it’s just more pleasurable to look at. I’m not sure how big of an impact this makes when you’re looking at really red or really blue ends of the CCT range, but in the 3000-4000k range it makes a difference.
I’d say if talking about Bridgelux strips, you’d want to go with 3000k or 3500k 80cri for veg, 2700k or 3000k 90cri for flower, and don’t mix strips of different colors because there’s likely no benefit and there are possible issues from an electrical standpoint (search for discussion of this earlier in the thread).
I literally was just reading about this coming across some of the same stuff you @nube mentioned.
Although, and I could be wrong, it seems like the sweet spot for gen3 might be the 4000k as @Pursuer mentioned or 3500k…
From what I read, the CRI 90 shifts the spectrum to the right putting the intensity of the reds more inline with the photosynthesis of the plants (I’m prob not saying that technically/correctly) and when I look at the typical color spectra on the spec sheet, it appears 2700-3500 are in the 100% range for the reds, while the 4000k might be around 96-98% in the reds? But if you look at the blue peak, while the 4000k still has 100%, the 3500k drops to around maybe around 76-78% with 3000k dropping to 50%?
So it seems like you get a lil better value with the 4000k, but at the same time I feel like someone mentioned you can have too much Blue, so in that regards maybe the 3500k is better?
I’m more interested in quality over quantity(yield)… if going for one kelvin and not mixing, for that quality goal, would you lean more towards 4000k or 3500k, or another kelvin for whatever reason?
Just to add more to the discussion those spectral relative intensity charts are graphed on the lights overall spectrum intensity but are not measured in a total output comparison way to each other, all they do is show percentages of what the light is made up of and where it may peak to how that tabulated in a relative intensity way.
An example is say the 3500k and 4000k values your referencing, the 4000k looks to have less red but more light over all compared to say 3500k but the 4000k blue spike is of a higher relative value that when graphed as that being 100% the relative intensity the red portion would be driven lower graph wise because the blue is higher intensity wise, now that doesn’t mean the 4000k is producing less red spectrum on an output perspective just that the spike of blue is higher to the point that it shifts the graph of the red portion.
Also the lm/w efficiency measurement is based around lumens and our eye perception which is a curve that spikes in the green region at a 555 nm, so color temps that end up producing more light in those regions will have a greater lm/w efficiency but that doesn’t mean they produce more light over all for our plants and what they use as @nube led onto.
All just to add more complexity to it, as for 3500k vs 4000k really its just that 3500k are more commonly in stock and thats about it, pictures of your plants will look better under 4000k though as its a more neutral white than a yellow tinged white, but growing wise the will be very close to one another.
And to add to @nube efficiency vs efficacy posts or to paraphrase in a less articulate manner, yeah bluer spectrum are more efficient at producing those photons though the plants use more of that energy to covert that wavelength to what they want causing the plant to be less efficient vs say a less efficient red leaning spectrum from an energy use perspective that is more efficient on the plant side of using that energy where both kinda work out to a point and within a range that are somewhat equal its just at what point in the equation is the efficiency drop happening is it at the light or at the plant. Alot more to it than that but to add a bit of thought to it.
I don’t know what you have or if that’s what you would still get today or for what I’m looking for in quality, but if you could get any bridgelux you wanted, to cover both veg and flower, what would it be?
3500-4000k gen 3 regular format
At 90 CRI?
For me, I’d go with 3000k or 3500k 90cri in the Bridgelux EB3 strips. My reasoning is that we want the fastest growing plants that also have the right shape. If we’re not space-limited, more red achieves that goal…up to a point.
However, if you look at things from a small plant perspective, or you just have limited height, go with slightly more blue like @Mr.Sparkle said: 3500k - 4000k EB3 80cri. In the past when I was doing small custom cab grows with 270w and 400w HPS, I would have killed for those strips.
But nowadays I don’t want small stocky plants because I’m in legalized land and don’t have to hide them. There’s 10% blue in the 2700k 90cri strips which is great for flowering, and 15% blue would be the max I’d want for a single sprout to harvest space.
Also, as Mr.Sparkle mentioned, the space under the curve isn’t what it appears to be. I also thought the same thing as you and I even mocked up a shitty drawing to ask the question on another forum. But this isn’t how it works, so this drawing is wrong because it assumed the curves were relative photon output compared to each other. They’re not:
That drawing is wrong for the reasons Mr.Sparkle alluded to. And red photons are more efficacious, so they’re better at growing plant mass than blue. And no, not just leaf and stem - flower mass specifically.
We have to get out of the “red and blue” mindset from the old bulb based approach. We’re no longer limited to that all or nothing perspective. Blurple failed because all the photons in the spectrum count, although some count more than others as mentioned above.
well i didn’t say 80cri specifically , 90’s work and push a bit further into the red but also have more light else where in the spectrum in order to make them more color accurate, me personally if 90’s are available id go for them and they will make for better pictures cause its all about those “likes” lol, usually its the 80’s that are in stock or available or have been in the past they do produce more light but at expense of having a more peaky spectrum, which if those peaks are in the blue or red wavelength spectrum then thats good for us and our application.
Really to me it doesn’t matter too much so long as we get light on plants in a somewhat efficient manner where they can use that light, saying that tough its more a range of what works and there is no definitive answer on whats best as everyone’s application will be slightly different whether short grow areas, using the lights for only flowering or only veg, to wanting to have color accurate light for viewing and picture purposes, whatever our opinions or thoughts are though they also change as we learn and experiment more or our applications changes its just what it is.
@Mr.Sparkle @nube thanks for the inputs…
So I was thinking about doing some smaller grows… I might get a 3x2x6 tent and flip it horizontally (so approx 3ft high then)… so it sounds like if I can find them, the 4K 90s might be best for that…
Would you go with a bunch of 560mm running perpendicular to the 6ft length or 1120mm running parallel? Or I guess three rows of 560mm running parallel as now that I think about 1120mm won’t really fill it up that well I think?
How many of each matched with what driver(s) would you say?
…
Reading back a lil up the thread, it seems like 25w - 35w per square foot would be adequate, so, for 12 sqft (2x6), 30 (560s) at 13.4w equals 402w divided by 12 would put me at 33.5w/sqft?
Three XLG-150-24-A drivers maybe?
One per 10 (134w)?
Could these be dimmed?
Or would that have to be either an HLG-150H-24A(or B)?
Actually think my plans are changing, gonna go for a small small grow to get things sorted/tested first, then expand…
So simply, any recommendations for a 2’x1’ area? @Mr.Sparkle @Gpaw @nube
5 560mms x 13.4w = 67w / 2sqft = 33.5w/sqft sounds like you guys said might be enough?
I like this cause I could order a twenty pack and then build out four cabinets unless anyone thinks that won’t work…
I am getting caught up tho on which driver, am I understanding that the AB version will give me the most flexibility as far as dimming? Would that work with a controller or just driver screwdriver? Lol
One of these I take it?:
Power Supply,AC-DC,20V,4A,100-305V In,Sealed,PFC,LED Driver,80W,HLG-80HSeries
$37
80W LED Driver Single Output Switching Power Supply 80 Watt, 20V @ 4A A Model
$36
LED Driver (CC, CV) 80W 4A Linear (12-20Vdc) 90-305Vac PFC Non-Dimming IP67 Metal Enclosure
$36
LED Driver Module 1-10V/Analog/PWM/Resistance 2.4A to 4A Single-OUT 17V to 22V 80W Wire Leaded
$38
OR XLG
LED Driver (CP) 74.4W 3100mA Linear (16.8-24) 100-305Vac PFC 0-10V, PWM, Resistance Dimming IP67 Metal Enclosure
$25
LED Driver (CP) 74.4W 3100mA Linear (16.8-24) 100-305Vac PFC Non-Dimming IP67 Metal Enclosure
$16!
Or other?
