Cheap LED Strips : A Viable Alternative

[nube]

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).

[GnomeyByNature]

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?

[Mr.Sparkle]

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.

[GnomeyByNature]

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?

[Mr.Sparkle]

3500-4000k gen 3 regular format

[GnomeyByNature]

At 90 CRI?

[nube]

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.

[Mr.Sparkle]

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.

[GnomeyByNature]

@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)?

[GnomeyByNature]

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?:

Mean Well
HLG-80H-20B

Power Supply,AC-DC,20V,4A,100-305V In,Sealed,PFC,LED Driver,80W,HLG-80HSeries

$37

Mean Well
HLG-80H-20A

80W LED Driver Single Output Switching Power Supply 80 Watt, 20V @ 4A A Model

$36

Mean Well
HLG-80H-20

LED Driver (CC, CV) 80W 4A Linear (12-20Vdc) 90-305Vac PFC Non-Dimming IP67 Metal Enclosure

$36

Mean Well
HLG-80H-20AB

LED Driver Module 1-10V/Analog/PWM/Resistance 2.4A to 4A Single-OUT 17V to 22V 80W Wire Leaded

$38

OR XLG

Mean Well
XLG-75-24-AB

LED Driver (CP) 74.4W 3100mA Linear (16.8-24) 100-305Vac PFC 0-10V, PWM, Resistance Dimming IP67 Metal Enclosure

$25

Mean Well
XLG-75-24

LED Driver (CP) 74.4W 3100mA Linear (16.8-24) 100-305Vac PFC Non-Dimming IP67 Metal Enclosure

$16!

Or other?

[Gpaw]

Hi @GnomeyByNature,

So… 5 of the 560mm Bridgelux Gen2’s. I see you want veg and flower in that space?
It is implied you want to drive the strips in parallel (my preferred method)

DS131 Bridgelux EB Series Gen2 Data Sheet 20171020 Rev A.pdf (940.9 KB)

The strips need 700mA for full power - and the nominal forward voltage is 19.5V.
At first glance, the HLG-80H-20 family looks like a good fit. If you have a look at Table 2 on page 4 (Bridgelux spec), they give some more detail on the max and min (we care about the max) of the forward voltage as ranging from 18.5 to 20.6V.
At worst case, 20.6V is a little too high for some of the HL80H-20 family (HLG-80H-20B & HLG-80H-20), the A versions (A & AB) can be tweaked up to 22V - so they are good!
That narrows your HLG options to HLG-80H-20AB (22V & remote adjust).
Some of the AB series drivers are difficult to find stocked - be sure to check!
Also, check with different vendors as they will stock differently)

The XLG-75-24 (& 24AB) has a maximum current output of 3.1 Amps which will only drive 4 strips to full power. It will still drive 5 strips in parallel but only to about 90%.

OPTIONS

Up-gunning to XLG-100-24 series gets you 4 Amps of current. Same for HLG-100H-24 series.

NOTE:
You will want a 100K linear pot (& knob) for the remote dimming control.

I’ll throw the driver specs in so it is easier for other folks to follow along.

HLG-80H-SPEC.PDF (760.6 KB)
XLG-75-SPEC.PDF (1.1 MB)

As questions if I’ve been unclear or made erroneous assumptions!

Cheers
G

[Mr.Sparkle]

@Gpaw

You will want a 100K linear pot (& knob) for the remote dimming control.

only on the AB or B models

And id say the XLG-75 or 100 in the H series as the 24 series issue being is they are limited amperage wise with the intention that they will be run at 24v not under that so say the xlg-100 with the bridgeluxs if you ever wanted to you could only max out at about 75w to the strips on the 24 model vs the H or L where you could get the full 100w, just something to consider.

Also to @GnomeyByNature doesn’t hurt to have an overspeced driver when its only a couple dollars more.

[GnomeyByNature]

@Gpaw and @Mr.Sparkle thanks for the tips… so I keep changing my mind with what I want to do lol but all that is still great to know as that may still be a route I’m trying to go, but what I really want to ask, maybe this is more geared towards @Mr.Sparkle, is if you have any links to a cheap micro build?

I think I’m still leaning towards a 2’ deep 1’ wide and maybe 3’ tall sort of box/cabinet/grow tent?

Also wondering what you guys think about the high output Gen3s? Seems like they are just double the leds/power in the same lengths and NOT twice the price (not that I can find them available)?

Also, in a grow space like I mentioned about, if it was you, would you prefer the 5, 560mm strips running in the 2’ direction, or I guess 10, 280mm strips running in the 1’ direction?

Only reason I like the 5 strips over the 10 is less wiring and screws lol

Also, as for the drivers, I guess I didn’t see a XLG, H variation but I’ll have to take a look…

Will that 100k potentiometer work with any of those A/AB drivers (like is the power a factor)?

Also, @Gpaw if I can, I think I’d like to go for the Gen3s over the Gen2s.

[nube]

They gave you all the links for a cheap micro build, friend. Literally everything you need is right there.

We all do this our first time building DIY lights so don’t feel bad, but I think you’re overanalyzing a $70 build. I get it if it’s your first DIY LED build, but believe me, when you finish it you’ll look back and wondered why you himmed and hawwed over a couple bucks or a couple photons when none of that stuff matters.

Don’t waste your time with the “high output” or whatever. Or the new gen of strips. You’re growing in such a small space that plant size and maintenance are your biggest constraints. More or newer tech won’t help you grow more or better weed compared to what the cheap Bridgelux EB Gen 2 3500k 2ft strips from the previous generation will do. Your small space simply doesn’t justify the added complexity and cost for almost no benefit.

If you could find the Gen 3 for almost the same price as the Gen 2, sure, that’s a no brainer, but high output isn’t what you want when you have such small confines. You want low output, highly distributed light engines blanketing your entire plants with photons. High output requires more space between lights and plants and you want the opposite - a system you can run 1/2" away from the plants without harming them to maximize your micro cabinet growspace.

There’s no benefit to more smaller strips, only more wiring and they cost more. Don’t waste your time if you can fit longer strips in your space. (You can.)

100k pot will work with all of those AB/B drivers. The A series has built-in pot that dims to 50%.

Use www.octopart.com as a part number search engine for all your electronics needs.

Let us know if you have any other questions!

[dequilo]

Good Day because I am old I still use tech from days gone by

Dad always said “if it ain’t broke don’t fix it”

as that maybe be correct over all but there are better things out there

LEDs back in 2001 sucked ass so did the Phototron

had one

so I would like to build a single panel to start with to cover a 2 foot by 4 foot

shelf to do SOG with six inch square pots

I reached out to @Guitarzan and he sent me of a list of what he used

for his build and it sounds as if it will do what I want

so I will be looking for help a long the way

all the best and this is a great thread

Dequilo

[nube]

What’s your budget and skill level with DIY electrical wiring, power tools, etc.?

[dequilo]

@nube

power tools,

smoke a lot of weed so I am careful with those

@nube

skill level with DIY electrical wiring

not a sparky but build to code and could/have wired houses and buildings

always error on the side of safe

I own my house free and clear would hate to burn it

@nube

What’s your budget

with in reason

just looking to build something that works for what i am trying to do

not having to troubleshoot my grow to figure out if it is me or

is it the cheap ass prebuilt light

that cost me three times what is worth

what I can do or do not know how to do I have a maintenance department

here at the plant with a full machine shop

they love projects and smoke the weed

all the best

Dequilo

[Guitarzan]

@dequilo

I reached out to @Guitarzan and he sent me of a list of what he used

for his build

You want to make sure you verify everything I told you with the folks in this thread. I initially ordered the wrong driver, but I reached out to @Gpaw, and he got me back on track. In fact, that’s who I checked with to make sure I picked the right one for yours.

Here’s the light I built for my 2x4:

I’m really glad I found this thread. Thanks to all for the great advice and support.

[The_Lazy_Hippie]

@Guitarzan Thats a beautiful built light.

[Joker]

Have to agree. Beautiful build @Guitarzan. And can I say I am shocked that @dequilo is looking at LEDs?! . Can’t wait to see your opinions after a grow.