Calling all DIY LED Gurus: New Challenge(?)

What's up fellas? I've been interested in LEDs for a while now, scouring through threads, and really digging the results you're getting lately. I can normally find any info I need, within threads, without asking questions, but now I need help from the pros.

I'm helping a couple of friends design their gardens, and would like to make lights for both, using as much of the same components for both as possible. I'm thinking of going with flexible LED strips with 3000k-4000k, Samsung diodes, and worked my calculations off of this particular page :

*Well, I guess I can't post the direct link yet, but the strips are found on AliBaba, and supposedly have the Samsung LM561C diodes @ 60/M. I found them searching LM561C on the alibaba site, offered through the seller called "Brightest"

(Obviously, there are about a million options regarding both strips, and sellers, and I haven't yet dealt with AliBaba, so any guidance there is also appreciated...especially if I don't have to deal with them, and can find someone comparable closer)

Now, one of these gardens will be a horizontal, over a 4x4 table with about 5ft of headroom, and the other is for a vert grow in a 4x4 tent. I have ideas for both, but the vert fixture is what I'm more concerned about figuring out the correct numbers for.

I guess the short question is: What are the minimum and maximum distances from vegetation should these be with acceptable PPFD?

For the horizontal garden, I don't want to be too close, and for the vert tent, I wanna make sure I'm close enough.

So, here's my idea for the vert fixture: Flexible LED strips wrapped around 6" duct, 24" long, with either a Vornado type fan under the fixture, blowing up, or a 6" duct fan installed at the top, sucking out.

Below is a diagram and my calculations, as far as I could figure. This is where I need your help deciding if the numbers add up, and I'm onto something, or if I'm waaay off. I'm shooting for around 400w power on each fixture if that would suffice, but the vert can afford to go to maybe 800w, if needed. The diodes should be about 21" from the walls, and less to the leaves, when the fixture is built.



If this seems doable to you guys, let me know how many of which drivers you would recommend, etc, and I'll build it asap, and see how well it works.

Any help, questions, or critiques are welcome and greatly appreciated!

Anybody? Bueller? Bumping for first page views....I know one of you guys gotta have an opinion on this idea

get a par meter

for design purposes, 20 parW/SF is about 900 umol/m2s in a garden with good reflectivity

46000 lumen is about enough for lighting up one square meter of grow surface. For vertical that would be a cylinder of 24" tall and an 10" radius (20 diameter). Where the radius is the distance between the center of the pole to the edge of the plants.

Although vertical growers tend to grow with much lower light intensities, so you could go up to say double that surface area (and half the intensity) and use a 20" radius (40"diameter). Somewhere between 10" and 20" would be fine.

These led strips aren't very efficient though. Are you sure you aren't wasting a lot of time, effort and money on something that could be done better with more modern led strips/cobs? Look at the Bridgelux led strips. Put a few of those 2' strips around a cylindrical surface and you would get something between 150lm/W to 175lm/W.

paging @Hybridway to critique the "aircloak"

also if you run the strips axially you can use hard strips

CobKits said:

also if you run the strips axially you can use hard strips

Click to expand...

Is there any heat problems from the strips going vertically?

there shouldnt be heat problems from strips at all. you dont even need a heatsink in some cases. the air tube is way overkill unless youre running them at the top of their limit

CobKits said:

also if you run the strips axially you can use hard strips

Click to expand...

Came here to say this...

Plus the Blux/Samsung strips come in 2' lengths, and are compatible with Zhaga optics

I know right, those 2' strips seem perfect for that. At least I contemplated it to go with a water cooling pipe in the middle.

I'm just a bit uncomfortable with the whole idea of vertical growing. I'd be afraid not to be able to reach the plants everywhere to train them properly and keep them at the correct distance from the lights.

CobKits said:

paging @Hybridway to critique the "aircloak"

Click to expand...

The AirCloak hu. This could actually work if done correctly, using solid duct.
The idea is cool though.
Could work w/ high powered Ribbon strips if they make them. Hard strips too using 40w+ each strip w/ a 1/4" between strips. @OLD MOTHER SATIVA could direct you to good strips for this.
I'd consider using multiple 20-30w cobs, thermal taped or glued directly to a solid aluminum duct (round, seamed, HVAC tube)
Although it's a cool idea, I don't see it working better then an hps in a cool tube.
Remember, hps is getting 150 lm/w too when utilizing the whole bulb 360•.
This actually makes me wonder why others don't skip the heat sink on cobs & just mount directly to square HVAC duct. I'd think that would be a good way to run many a cob soft while majorly cutting down build cost & be able to exhaust the heat.
Can anyone tell me why that's a bad idea? If not, I was originally thinking of duct work vented cases w/ thin sinks.

Thanks all you guys for taking the time to help- I really appreciate it!

I thought about using hard strips mounted vertically, either hanging freely from some sort of ring, or hard mounted to an angle iron frame, with a fan underneath, blowing heat up and away toward the ceiling exhaust...then thought about all that soldering to connect them at each end, strips every 1/2" or so...

That's when I had the idea to use the flexible strips that come in 5 meter reels, which only need soldering every 5 meters or so, and wrapping them around the duct, right next to each other, all the way down. This should put a diode about every 1/2", all around. The duct, I'm hoping, would be sufficient as a heatsink...especially if there were a fan underneath, blowing through the inside of the duct, as well as up past the diodes on the outside of the duct, and moving canopy air up and around as well.


Now that I can post links to show you which strips I was looking at, maybe you guys can help me weed through the many various strip models and sellers, to find the appropriate strips and drivers? I'm sure all these spec numbers make more sense to you than me still.

Of course, if the rigid strips would work better, by all means, let me know. I just figured from looking at a bunch of different flex strip specs, maybe i could find a configuration that would work well enough with them.

Most of them are 60 diodes per meter of strip, and around 100w to power each 5 meters. Here are a couple of listings that I found. I used the first one when trying to make the rough calculations in the diagram in the initial post:

**Links added**

https://brightest.en.alibaba.com/product/60564289820-218640161/SAMSUNG_LM561C_led_strip_light_60leds_m_5630_type_flxible_strips.html?spm=a2700.8304367.0.0.2uWIxP

A slightly higher power strip, but maybe I could use like 12 meters per fixture, because they're double stacked? I dunno...

https://brightest.en.alibaba.com/product/60638958342-218640161/High_lumens_15mm_Width_2oz_PCB_SMD_5630_5730_Warm_White_Led_Light_Strip.html?spm=a2700.8304367.0.0.irdJ6M

So, if I hang a fixture made from 6" diameter duct, vertically, in the middle of a 4x4 tent, there should theoretically be 21" from diode to outside wall of tent max, and slightly more to the outside corners of the tent. Now, the light won't actually have to reach that far, because the plants will be closer, and I can always lean them in slightly toward the light. I'm planning 8 plants, 2 per wall, up to 4 ft tall, and 18-24" wide each. That would be as full as I could realistically fill the tent, and the goal, ultimately.


All that being said, I'm hoping it's a relatively straight forward question (/answer), to ask if the LM561C diodes without optics, at 120* angles, will reach canopy say, 18" away (likely less), with sufficient lighting? I know it's a little trickier to calculate, as the fixture will be round, lighting 4 flat walls / canopies, so the numbers will probably sound insufficient. I'm just hoping all that 120* overlapping light will help with coverage. I don't mind using the fixtures at 100% power if needed, and realize this fixture will probably call for 4-600w worth of strips, at 23m of strip per fixture, around 100w per 5meters, but it would be nice if I had the option to run softer, if possible.

Like I said, I'm not necessarily against COBs, or hard strips, if they'll work better....I Just didn't see COBs as the most efficient or economical way to configure a fixture for a (plant-surrounded) vertical space. It seems like I'd probably want at least 16 COBs, plus heatsinks, etc, and it started adding up pretty quick n ugly lol.
If any of these strips would work, and the prices I'm seeing aren't hiding a bunch of costs, I should be able to get away with paying about $160 for 600w worth of diodes, plus cost of driver(s), no extra heatsinks, if a fan and repurposed duct will shed heat adequately.

Well, I hope I've made things more clear, but apologize if I've rambled or repeated too much. I'm just really interested in seeing this idea come to life, but only if you guys think it could work decently. Unfortunately, we don't have the R&D $$ to waste, or I would've tried to throw one together, and surprised you, rather than being another DIY LED newb with a million questions

@wietefras, I'm trying to picture the calculations you're giving me, but I'm probably not following 100%, due to the whole cubed canopy vs lumens of fixture...or something... but I think we're trying to get similar ideas across to each other, and I appreciate the help! I think I read specs on at least one of these flex strip pages where they said the lumens / watt was supposedly between 160 and 170something.
Regarding not being able to reach the plants in (this particular) vert setup: All plants are easily accessible / removable, each having their own bucket and trellis. If you have access to 3 sides of the tent, the only time you may have to remove a bucket would be to get at the 2 plants on the back wall. Otherwise, you can spin each plant around for the front, or work through the back of the trellis. If you can only get in the front of the tent, you'd probably have to take a couple plants out first, to reach the ones in back.

D'oh...I guess I needed 2 more "likes" before I could edit the links in, but thanks, @Hybridway !

Hybridway said:

This actually makes me wonder why others don't skip the heat sink on cobs & just mount directly to square HVAC duct. I'd think that would be a good way to run many a cob soft while majorly cutting down build cost & be able to exhaust the heat.
Can anyone tell me why that's a bad idea?

Click to expand...

would be alright but i think cobs def suffer above 10-20W on thin materials even with good airflow. i think airflow over a shrouded real heatsink might be better for cobs at normal current and the "Stick on the duct" method would work better with a ton-of-cobs-at-low-power approach which is another way but once the # of cobs get super high strips make a lot of sense

joecanna17 said:

Thanks all you guys for taking the time to help- I really appreciate it!
@wietefras, I'm trying to picture the calculations you're giving me, but I'm probably not following 100%, due to the whole cubed canopy vs lumens of fixture...or something... but I think we're trying to get similar ideas across to each other, and I appreciate the help! I think I read specs on at least one of these flex strip pages where they said the lumens / watt was supposedly between 160 and 170something.

Click to expand...

Well you quoted 46000 lumen from 460W. So that sounds like 100lm/W to me. If I got either of those wrong then the calculations are incorrect, but you should be able to follow what I meant and use the correct figures.

The formula outer surface of a cylinder is: surface = 2π * radius * height
Or the other way around: radius = surface / 2 / π / height

So if you have the amount of light (lumen or umol/s PPF), then divide that by the desired light intensity (between say 300 and 900umol/s/m2 PPFD) and you get the surface area for which this light would be sufficient. Then calculate the radius of the cylinder so that you match that surface area.

If you are using 3000K 80CRI smd's then lumen to umol/s conversion would be around 69 to 70. So 46000lumen would then be equivalent to 650umol/s. It's all just ballpark figure anyway.

Regarding not being able to reach the plants in (this particular) vert setup: All plants are easily accessible / removable, each having their own bucket and trellis. If you have access to 3 sides of the tent, the only time you may have to remove a bucket would be to get at the 2 plants on the back wall. Otherwise, you can spin each plant around for the front, or work through the back of the trellis. If you can only get in the front of the tent, you'd probably have to take a couple plants out first, to reach the ones in back.

Click to expand...

OK thanks. Maybe I should just try it once.

Man, I'm gone a few days, come back, and men are wearing rompers?!?

Anyway, thanks for the formulas! I appreciate the ballpark figures, and am still narrowing down exactly which strips and power supply, etc to order.

To add customization and complication, supposedly you can order these strips to your own specs as far as color temperature, down to ratios of diodes at specific wavelengths, cri rating, etc, but I was planning on 3500k all around, for simplicity sake.

So, basing a vert fixture build off the strips in the first link I posted, I would need almost 23 meters of strips. That would allow them to be right next to each other, all the way down a 24" section of 6" duct pipe, providing a diode approximately every 1/2". Since they're 20w/m (100w/5m), and I need 23m, each vert fixture would be 460w. I also looked at some strips that were 120w/5m, which would come out to 552w. (2nd link I posted)

Either way, I was wondering if I could use an HLG-600H and wire all 23m of strips to it, or is it a lot more complicated than that?

I'll be ordering multiple drivers regardless, since I have to make flower and veg lights, both vert and horizontal fixtures, but I'd like to keep them to a minimum per fixture, if possible.

What do you guys think?

I'm hoping that once this system is completed and producing, it will give a whole bunch of folks a reason to try vert ...and LEDs ...but that's a few months worth of testing away, at least.

joecanna17 said:

Man, I'm gone a few days, come back, and men are wearing rompers?!?

Anyway, thanks for the formulas! I appreciate the ballpark figures, and am still narrowing down exactly which strips and power supply, etc to order.

To add customization and complication, supposedly you can order these strips to your own specs as far as color temperature, down to ratios of diodes at specific wavelengths, cri rating, etc, but I was planning on 3500k all around, for simplicity sake.

So, basing a vert fixture build off the strips in the first link I posted, I would need almost 23 meters of strips. That would allow them to be right next to each other, all the way down a 24" section of 6" duct pipe, providing a diode approximately every 1/2". Since they're 20w/m (100w/5m), and I need 23m, each vert fixture would be 460w. I also looked at some strips that were 120w/5m, which would come out to 552w. (2nd link I posted)

Either way, I was wondering if I could use an HLG-600H and wire all 23m of strips to it, or is it a lot more complicated than that?

I'll be ordering multiple drivers regardless, since I have to make flower and veg lights, both vert and horizontal fixtures, but I'd like to keep them to a minimum per fixture, if possible.

What do you guys think?

I'm hoping that once this system is completed and producing, it will give a whole bunch of folks a reason to try vert ...and LEDs ...but that's a few months worth of testing away, at least.

Click to expand...

I'm growing w/ vertical LEDs.

CobKits said:

would be alright but i think cobs def suffer above 10-20W on thin materials even with good airflow. i think airflow over a shrouded real heatsink might be better for cobs at normal current and the "Stick on the duct" method would work better with a ton-of-cobs-at-low-power approach which is another way but once the # of cobs get super high strips make a lot of sense

Click to expand...

Water cooled best way to have cob's on a stick.

joecanna17 said:

What's up fellas? I've been interested in LEDs for a while now, scouring through threads, and really digging the results you're getting lately. I can normally find any info I need, within threads, without asking questions, but now I need help from the pros.

I'm helping a couple of friends design their gardens, and would like to make lights for both, using as much of the same components for both as possible. I'm thinking of going with flexible LED strips with 3000k-4000k, Samsung diodes, and worked my calculations off of this particular page :

*Well, I guess I can't post the direct link yet, but the strips are found on AliBaba, and supposedly have the Samsung LM561C diodes @ 60/M. I found them searching LM561C on the alibaba site, offered through the seller called "Brightest"

(Obviously, there are about a million options regarding both strips, and sellers, and I haven't yet dealt with AliBaba, so any guidance there is also appreciated...especially if I don't have to deal with them, and can find someone comparable closer)

Now, one of these gardens will be a horizontal, over a 4x4 table with about 5ft of headroom, and the other is for a vert grow in a 4x4 tent. I have ideas for both, but the vert fixture is what I'm more concerned about figuring out the correct numbers for.

I guess the short question is: What are the minimum and maximum distances from vegetation should these be with acceptable PPFD?

For the horizontal garden, I don't want to be too close, and for the vert tent, I wanna make sure I'm close enough.

So, here's my idea for the vert fixture: Flexible LED strips wrapped around 6" duct, 24" long, with either a Vornado type fan under the fixture, blowing up, or a 6" duct fan installed at the top, sucking out.

Below is a diagram and my calculations, as far as I could figure. This is where I need your help deciding if the numbers add up, and I'm onto something, or if I'm waaay off. I'm shooting for around 400w power on each fixture if that would suffice, but the vert can afford to go to maybe 800w, if needed. The diodes should be about 21" from the walls, and less to the leaves, when the fixture is built.



If this seems doable to you guys, let me know how many of which drivers you would recommend, etc, and I'll build it asap, and see how well it works.

Any help, questions, or critiques are welcome and greatly appreciated!

Click to expand...

Use square aluminium stock wide enough to mount your strips. Connect shrouds at one end vents one the other connect the shrouds to the exhaust duct and duct cooled led strips.

Hybridway said:

I'm growing w/ vertical LEDs. View attachment 3946205View attachment 3946206

Click to expand...

Lookin nice and clean! Your girls will be bathed in light!