Could really use some help...max efficacy 65PPF/SQft in an 8x8, please?

Hi everyone. New here...but i keep ending up lurking this forum when i am doing research. You guys know your shit! Anyway...I was looking for some help and thought this might be the place to ask. Before I get into this....if you read my post and you know your shit enough to really help me, I promise to read links you give me and to help teach others so that your help travels further. Thank you in advance!

I am trying to make the switch to super efficient LEDs for a few large spaces. I have learned more about light that i ever thought i would need to know, and I am loving it! My questions pertain to what kind of overall setup i should use to achieve my goals, and where i can learn parallel wiring (if i should even use it?)

My largest is an 8ftx8ft, so let's start there. I am looking to achieve 65PPF per square foot with an intensity that's up to 800-1000 or so. I do autos and photos, but want to experiment with pushing autos without CO2 (I have not yet learned to run a proper sealed tent).

Lately I have really been leaning towards running an insane number of COBs (1+ per sqft), and running them at 500mA to get max efficiency. I know i will need to use more COBs in order to get the same PAR output, but i figured that could help me spread my light more evenly. One thing that drew me to the COBs is the ability to assemble them myself(huge tech guy), and another is the ability to raise and lower individual COBs over plants that are shorter/taller than those around them. I had considered going with Geitan COBs...i imagine the Chinese electronics may not be loved by all here, but Geitan looks like good quality, and I can always test the lights i get for PAR output and efficacy.

However...I keep coming across QBs. I almost want to learn where to get large QB style PCB boards and make a QB from scratch myself for fun.(I know how to solder a SMD to the board itself, but lack proper knowledge of parallel wiring.) I think my approach of maximizing the number of COBs and running them at minimum amps might work even better with a QB full of Samsung SMDs, but I'm not quite sure.

I've been really looking at those HLG Diablo boards, too. I am trying to explore if i could use parallel wiring to wire together a shitload of Diablo boards for my spaces. Unfortunately, i can't seem to find really good or really clear info on parallel wiring. The few good videos i have found seem to be in Hindi, or English that is actually accented enough for me to struggle to understand, which is making learning the information super difficult. Could anyone help me find good resources, or could someone take the time to break it down for me? Is it possible to use arrays of QBs to beat the efficiency of soft run COBs? I would be beyond grateful if someone could help. Thank you for reading!

-Monosoto

I'll try to answer

1) I tried the whole cobs per sqft back in the day. I ran each at 60w and would raise or lower individual cobs over plants. Dude it was such a pain in the ass. Not recommended.

2) QB boards are cool. I think they are recommended here by some. I'll let them chime in. Making your own PCB for a light is fairly simple. The hard part is voltage matching between parallel circuits so you don't run 1 strip brighter/hotter than the other. Not a huge deal with strips, but with individual leds it can make or break a design.

3) What current are you planning to run? If it is low enough, you might be able to find a driver that can run them parallel, most likely not though so throw that idea out the window. Based on the little I know about them they run at a pretty high current. I'll link a simple explanation of parallel wiring so you understand why that is a huge issue when wiring in parallel.

Some guys will be really great help for selecting premade and DIY lights here. I personally always DIY. I'm also a diode whore so I will always recommend EB Gen 3 strips.

Here is a link that explains pretty well: https://www.ledsupply.com/blog/wiring-leds-correctly-series-parallel-circuits-explained/

If you need more help with series parallel let me know. I can ELI5.

Welcome, mono.

You're working with 5.95 sq meters of area. I'd shoot for a PPFD of 800, so you will need (5.95x800umole/m2)=4760 umole PPF.
This is 'how much' light will be needed to achieve the desired intensity.
Now comes the tricky part-what to use to generate this much light.
I started with cob arrays(still use them) as well as strips and boards.
If I was planning on something like you're doing, I would look at those form factors before using cobs,
There a shit-ton of domestic sources for boards and strips but alibaba has some decent knock-offs. Buyer beware.

Hey @mono808 welcome!

That's a pretty big space. DIY will save you a LOT. Your best bet truly is boards. Strips are great too, but you'll be dealing with a LOT of them and boards can cover a lot of canopy.
Parallel wiring is as simple as this:
Your bringing a positive and negative from the driver to each and every COB/Board/strip. That's it
Series is starting the positive in the first COB/Board/Strip, connecting them all with a single wire in between however many used, and finishing the circuit with the negative from the driver to the last one in the group.

Thanks for the warm welcome everyone! You guys are awesome, thanks for the help!

@4ftRoots - 1.You make a good point, i probably don't want to bother with micro adjusting the lights constantly. It makes more sense to place similar strains in the same area and raise and lower panels above them. 2. I figured getting as many COBs as i would need from the same run would be difficult, and make thermal runaway a serious concern. I had wanted to run around .5A, but it seems like you have to do parallel to get it that low, but i was trying to maximize efficiency. 3. Fair enough, thanks for the advice! I really want to take the DIY approach to save money, and i love putting time into DIY projects so it's right down my Alley. The Samsung Q/F boards are the bees knees, right? I haven't gotten a chance to read your link yet, but it looks like exactly what I need, I will read it in a bit, thank you!

@GBAUTO - Yeah the COBs vs Strips vs QB dilemma is really where I'm stuck. I'm trying to find the cheapest highest efficiency way to run the cleanest light I can. I actually have more space than i listed to work with, but am limited by available amps vs. available space until I can make some upgrades. One of the main reasons I had looked at COBs was that the Chinese market for them looked good. I've worked at an ISO certified manufacturing plant in America and those requirements are quite strict. It makes me think that they make a quality product, and AliBaba backs your arrangement. With that being said, I'm weary to buy a QB from a Chinese supplier because I would worry about getting the correct diode/binning, and with the binning, it would be nearly impossible to prove unless there was a major difference. In any case...thanks for the input, I am leaning more towards strips of boards at the moment. COBs seem like they might be a bit much for this project, and it may be easier to get similar/better performance from the right QBs.

@Airwalker16 - Yeah, and I've got almost that much more available to me if I want to use it. I'm limited by low amps until I can afford a few upgrades, so I'm also trying to balance how big of a garden I can run with my power supply, because surely the available space could provide a bigger garden than I can power. I really like the look of the Diablo boards from HLG, but I need to do some math on the available options. I am weary about trusting a foreign company to give me the exact diodes that they claim, but that may be a feasible option. I haven't looked at Alibaba too much though, I can't imagine a proper looking board from there can be too much cheaper than a big order of Diablos.

Thanks everyone for the warm welcome and the help! I'll keep everyone posted.

@mono808

Ah I get ya. You had it backwards. Parallel can give thermal runaway. Series will just make them much harder to adjust. If instead, you get a single driver per board / set of boards you can adjust them together and it is no longer an issue.

Running at low current would work easy. Lots of drivers can handle low current. My comment was based on the diablo boards which have a max current of 5A. Holy crap!

DIY will save you a ton of cash, whether you decide COBs, strips, or boards, diy will be your best bet and allow you to tailor it to your space.

@4ftRoots - Yeah I think my multitude of questions made it tricky for us to be on the same question at the same time, lol. I see what you were saying now. I think part of my issue is that i only kind of understand how to use things like resistors and fuses to prevent issues in a parallel setup, but I am thinking that a parallel setup might help me keep my Amps usage low, while also helping me spread my light distribution and maxing out efficacy. That link you gave me was exactly what I was looking for, and I think once I've read all of it I will much better understand the gaps that I am having!

A couple things ill mention, is when you do end up building your fixtures, do smaller more manageable builds. Do not just build 4 fixtures for 4x4s. At LEAST do 8- 2x4 fixtures. You'll be glad you did for hanging adjustments, variability in canopy heights might require half the 4x4 to be up more than the other half. This will also get you to use more drivers rather than using larger ones like the 480/600's from meanwell, so if one craps out, you're still half lit. But there are some SERIOUSLY more cost effective drivers available, so the HLG model isn't your only option. XLG and ELG(75% output on 120VAC though) do dim and are a bit less in price, then you have the LRS models that don't dim, but are very very affordable and still have a 3 yr warranty. BUY YOUR DRIVERS WITHIN YOUR COUNTRY. They DO Shit on you sometimes. Personally ive had to RMA 4 of mine for repair.
Also, heat from the drivers is the main culprit for the MINIMAL amount these builds do put off. So keep that in mind if you'll want to use it to your advantage or remotely mount them outside the area. LED environments, in case you didn't know, benefit from 77-85℉ rather than 68-75℉ like HPS runs.
Boards from China are going to probably be what you end up doing to be honest. You've got a big space to blanket with diodes and boards can be as low as $4/PC now in larger orders or if you use LM561C's instead of the LM301B's. There are COUNTLESS members here using them and that have been for years now. They are solid. Especially Meiju and KingBrite. I can't vouch for any others really. I have though, heard good things about Bava.
You'll also need to factor in whether you spend money to heatsink each board individually with single slates, use double/triple slates that fit 2/3 on them(shipping can get pricey though with their lengths), or whether you decide to just buy enough boards to where you're able to run them at a lower current where heatsinking isn't even needed. Which is what I recommend you do. Boards weigh so little compared to heatsinks and are the easiest and best prices thing to ship. Plus more diodes ran at a lower current means more lumens per watt and far more EVEN coverage.
Just some things to think about.

I have 5 heatsinks over a 9' x 3' and that's just about right. 8 heatsinks seems like too much to adjust in a 4'x4' to me.

Oops I mixed this up with a 4x4 thread. I still don't see how you can fit 8 2x4 fixtures in an 8x8. Seems like there would be no space between fixtures, too cramped.

CaliWorthington said:

Oops I mixed this up with a 4x4 thread. I still don't see how you can fit 8 2x4 fixtures in an 8x8. Seems like there would be no space between fixtures, too cramped.

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I have 4 2x2's in my tent static at the top. I love it. Reminds me of a greenhouse with the diffusion cover.

4ftRoots said:

I have 4 2x2's in my tent static at the top. I love it. Reminds me of a greenhouse with the diffusion cover.

Click to expand...

Yeah if they're static it makes more sense. I'd like to do a tent like that. It just seems to me that if the entire space is taken up by fixtures, they'll be bumping into each other when you adjust them.

CaliWorthington said:

Yeah if they're static it makes more sense. I'd like to do a tent like that. It just seems to me that if the entire space is taken up by fixtures, they'll be bumping into each other when you adjust them.

Click to expand...

You don't make them exactly 2x4 homie. More like 44"ish X 21"ish

Airwalker16 said:

You don't make them exactly 2x4 homie. More like 44"ish X 21"ish

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I see. That works, then.

I would not say its a disconnect but 65PPFD per square foot is a big number relative to 1000PPFD on the canopy and suggests you want to hang em high, whats your height to canopy. 150 strips will give you very even 1000ppfd even at 36 inches but will be less that 40ppfd/sqf
cheers

CaliWorthington said:

Yeah if they're static it makes more sense. I'd like to do a tent like that. It just seems to me that if the entire space is taken up by fixtures, they'll be bumping into each other when you adjust them.

Click to expand...

Yeah thats pretty much what happened. I had the idea to raise and lower at first. But what a pain in the ass when they are so close together.

welight said:

I would not say its a disconnect but 65PPFD per square foot is a big number relative to 1000PPFD on the canopy and suggests you want to hang em high, whats your height to canopy. 150 strips will give you very even 1000ppfd even at 36 inches but will be less that 40ppfd/sqf
cheers

Click to expand...

I agree even something like the output on a 480W driver (550W) in a 1.2m2 space is insane...
www.leonled.co.za
Here are some budget ideas you can DIY your own way

Hey everyone! I've been swamped lately so I haven't had time to stop back in. The good news is I got everything figured out. I wanted to go with the HLG 650-R (3 of them) because I like the efficacy and the spectrum, but the shape of it didn't go well with the shape of my room.

I thought about going with four 550-RSpecs, and if I would have done that, I could have moved up to a 10x10 tent. That's still tempting.

Ultimately, I learned a lot more about drivers and LEDs and the math behind them (Tracking down a proper explanation of QER factor took forever!)

For the 8x8, I'm going to use twelve Diablo boards. I forgot that I don't have to buy the 650-R specifically, so I've opted for mouting them in pairs to heatsinks and I'll either run them in pairs (of pairs) to a driver that can handle 4, or I'll wire them in pairs to a driver per pair and wire the drivers power cables into pairs. I'm still looking at the math for the efficiency. I'm limited by available power, so using an amp or two less overall could be a big help.

As for the 65 PPF per square foot....if someone wants me to type up an example and calculate through, I could when I have a little more time. In short....i want 65 PPF of USABLE light. I don't mean a 650W (at the wall) light will cover 10sqft. 650W at the wall x efficiency rating. The efficiency rating of an LED ran around 500mA tends to be about 65%, that is, 65% of the 650W gets output as PARW or PAR Watts, and 35% gets put out as heat watts (this is what your heatsink size should be based on). Also, PAR Watts obviously stands for Watts of photosynthetically active radiation, which is generally accepted as 400-700nm, but I think it's been adequately proven that 300-800 is more accurate. Even if it weren't more accurate, it would be smart to calculate it that way due to the absorption curves of some of the non-photosynthetic processes of the plant that begin in those ranges. (Anthocyanin absorption curve, B-carotene, Zeaxanthin, ect...) So, although I am counting PAR Watts, I'm counting a slightly bigger range than normal. My QER isn't adjusted for the range I'm using, but I'm going to figure out how to calculate it sometime this week. In any case, I haven't decided what current I'll run my boards at, but it'll either be 1400 or 2100, so it won't be 65% efficiency. Probably more like 55%, and I'm also accounting for around 10% loss between the light and the environment, although I do have reflective walls. This does come out to being slightly more than 65 PPF per square foot, but I may use some natural CO2 just to increase ambient levels occasionally. I think it only takes around 700 total ppm (so only around 400 more than ambient) to allow the plant to take 1500 PPFD, so it should be fine. I just typed this up really quick, so please forgive any obvious errors, thank you again everyone for all of your help!