indecision has struck. Effeciency vs delivery.

So I'm planning an upgrade for a lighting system. It's a veg/flower unit. I've narrowed it down too 3 choices and was wondering if any of the resident experts would be willing to throw their $0.02 in. I have an HLG-120H-1050A driver that I want to utilize for this project, I also intend to instal a lens over any emitter used Link to lens

Space: 36"Lx18"Dx60"H ~(90cmx45cmx150cm)

Choice 1: Five vero 18's, 4000k, 80cri, on a 4.85"x24" heatsink from heatsinkUSA with a single 5v 120mm usb fan. Cost to build ~$250, ~41% efficient, $3.90/parw .

Choice 2: Four vero 29's, 4000k, 80cri, on a 4.85"x24" heatsink from heatsinkUSA with a single 5v 120mm USB fan. Cost to build ~$300, ~47% efficient, $4.17/parw.

Choice 3: Two CXB3590's, 4000k, 70cri, each on individual 3.945"x4" heatsinks from heatsink usa, each with a 5v, 80mm USB fan. Cost to build ~$300, ~49% efficient, $4.11/parw.

Choice 4: ????? Suggestions ?????

I'm personally leaning toward the CXB3590. I think it would look cleaner, simple, 'solid state' with all moving parts hidden and tucked. However I'm wondering if only two points of delivery is enough, or if I would be better suited to use slightly less efficient emitters, but with a greater number of them for better light distribution.

i"d probably go with the 4 vero 29 given that 1050mA is harder than I like to drive vero 18. I do run my vero 29 at around 1050mA though. (4 on a 1400 driver pulling 1200mA, 2 using individual 1050mA drivers)

4 x cxb3070 AD might be a good choice for that too.

churchhaze said:

i"d probably go with the 4 vero 29 given 1050mA is harder than I like to drive vero 18.

4 x cxb3070 AD might be a good choice for that too.

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I guess my next question would be, why four over two?

bicit said:

I guess my next question would be, why four over two?

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4 would allow the canopy to get closer to the lights without burning or growing unevenly. The fewer cobs, the less 'diffuse' the light is.. (don't know what term to use).

With one powerful beam, it's like alaska on the outer perimeter, and Ecuador in the center. Some plants see the sun on the horizon, while others see it directly overhead. Imo, a better question is, what are the advantages of 2 vs 4? Imo, you got the main reason.. convenience, cost(maybe) and simplicity.

(edit: this is assuming equal efficiencies and thermal conductance relative to the cob's total heating surface area.)

I'm stuck between option one and three. No room for suggestions, as you've narrowed down the best possible choices.

The only thing going for option three is the efficiency boost, which is ~8%; a big boost. The downside to this option is the intensity for such a small grow space is going to eventually catch up to you or rather so your plant(s). I work in the same tent size and I can tell you from experience, you don't want too much intensity in one given spot or your plants will turn into albinos during budding.

On the other hand, you have the x5 Vero 18s that are going to grant you the very best spread of light to your plant(s). Additionally, this setup (as well as option two) allows for every piece to be attached to a central hub (no shared wires between heat sinks via driver).

Option two is tempting but is more expensive then option two and doesn't offer that fifth point of light distribution.

So, better light distribution and affordability (option one) vs. better efficiency (option two) vs. best efficiency despite messy wiring (option three).

Hope this helps you a little, Bicit.

Seems like 18"x18" space would be ideal per each 3590 emitter considering you plan on using a lens. I would lean towards a DIY reflector though... I think with some experimentation after the light was assembled and right materials you could come up with a custom reflector that best suited the space and planned distance from canopy.

Rahz said:

Seems like 18"x18" space would be ideal per each 3590 emitter considering you plan on using a lens. I would lean towards a DIY reflector though... I think with some experimentation after the light was assembled and right materials you could come up with a custom reflector that best suited the space and planned distance from canopy.

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Lol, what?

What about what? The reflector?

If so, I was playing around with some reflective material a few days ago. I found that for any given height I could angle the material to optimize a given footprint. So what I'm saying is, build the light, hang it at a distance that will be appropriate for the intensity, find the angle necessary to maximize the footprint at that height and then build the reflectors at that angle.

It's a better option for a specific space than deciding on a 60 or 90 degree lens/reflector and then having to find the optimal distance from canopy after the fact.

Edit: If you mean the 18"x18" comment, 18x36 is 2 18x18s... ideal for two emitters.

Rahz said:

What about what? The reflector?

If so, I was playing around with some reflective material a few days ago. I found that for any given height I could angle the material to optimize a given footprint. So what I'm saying is, build the light, hang it at a distance that will be appropriate for the intensity, find the angle necessary to maximize the footprint at that height and then build the reflectors at that angle.

It's a better option for a specific space than deciding on a 60 or 90 degree lens/reflector and then having to find the optimal distance from canopy after the fact.

Edit: If you mean the 18"x18" comment, 18x36 is 2 18x18s... ideal for two emitters.

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I do plan to experiment with reflectors. But for the moment a lens is simpler.

I have a scaled prototype made our of poster board. Gotta do some testing

Rahz said:

What about what? The reflector?

If so, I was playing around with some reflective material a few days ago. I found that for any given height I could angle the material to optimize a given footprint. So what I'm saying is, build the light, hang it at a distance that will be appropriate for the intensity, find the angle necessary to maximize the footprint at that height and then build the reflectors at that angle.

It's a better option for a specific space than deciding on a 60 or 90 degree lens/reflector and then having to find the optimal distance from canopy after the fact.

Edit: If you mean the 18"x18" comment, 18x36 is 2 18x18s... ideal for two emitters.

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Yeah... I get the math and all but the logic... it's a little fucky if you ask me.

Have you grown in a five foot tall grow space before? Unless you do some LST or SCROGGING, chances are that the plants you're growing are going to reach heights of around four feet, if not more, eventually leaving you with little to no space between lights and budded-canopies.

"Hmm, do you smell something burning?"

"O, that's just my herbs."

I understand that the driver B picked out runs 1050mA but you're advising two 3590's.. with reflectors... in a five foot flowering tent lol.

I scrog in a 2x4 about 6'6" high. I have had run away stretching with some strains and have had to move the fan to the outside of the tent. Normally I can keep the plants under 4 feet though, that's 2 plants in DWC.

So it is a good point you make. Though if you had made it a post sooner it would have saved me some typing and guessing.

Rahz said:

I scrog in a 2x4 about 6'6" high. I have had run away stretching with some strains and have had to move the fan to the outside of the tent. Normally I can keep the plants under 4 feet though, that's 2 plants in DWC.

So it is a good point you make. Though if you had made it a post sooner it would have saved me some typing and guessing.

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Hehe, your typing and guessing was not in vain, I can assure you.

AquariusPanta said:

Yeah... I get the math and all but the logic... it's a little fucky if you ask me.

Have you grown in a five foot tall grow space before? Unless you do some LST or SCROGGING, chances are that the plants you're growing are going to reach heights of around four feet, if not more, eventually leaving you with little to no space between lights and budded-canopies.

"Hmm, do you smell something burning?"

"O, that's just my herbs."

I understand that the driver B picked out runs 1050mA but you're advising two 3590's.. with reflectors... in a five foot flowering tent lol.

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This is replacing a old tired 600w metal halide. Might be exaggerating a bit.

bicit said:

This is replacing a old tired 600w metal halide. Might be exaggerating a bit.

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I've never used anything but LED to grow. What I HAVE done is grow in a five foot tent, while using Vero 18's, outputting each ~30W (~30V, 1050mA) and found the 'weak' spot for bleaching, which was ~4-5 inches. So using that logic, I know that going from 30V to ~70V, at the same current, for a COB is going to leave a stronger footprint, thus issuing the concern of using reflectors or even 3590s in such a short space.

Have you used COBs before, I can't remember?

AquariusPanta said:

I've never used anything but LED to grow. What I HAVE done is grow in a five foot tent, while using Vero 18's, outputting each ~30W (~30V, 1050mA) and found the 'weak' spot for bleaching, which was ~4-5 inches. So using that logic, I know that going from 30V to ~70V, at the same current, for a COB is going to leave a stronger footprint, thus issuing the concern of using reflectors or even 3590s in such a short space.

Have you used COBs before, I can't remember?

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Well the intent of using the lens is to 'focus' the light, reducing spill and allowing it to be mounted further above the canopy without lighting the walls. The intensity would be less of a concern at about 18" would it not? I typically scrog and am dabbling in the art of mainlining. Honestly, my solo cup entry is the first time I've left any plant untrained in some manner.

bicit said:

Well the intent of using the lens is to 'focus' the light, reducing spill and allowing it to be mounted further above the canopy without lighting the walls. The intensity would be less of a concern at about 18" would it not? I typically scrog and am dabbling in the art of mainlining. Honestly, my solo cup entry is the first time I've left any plant untrained in some manner.

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Lenses or reflectors are going to require you to raise your lights further away from the canopies, as your forcing more light photons into a given spot. I'm sure you understand that concept.

If I recall correctly, most pots, plastic and fabric, stand no less than 12" when filled with soil. Add in the fact that your fixture, with required air flow space, is going to take up around 6". Let's say 8" is the closest the COBs, without reflectors or lenses, can be from any part of the canopy. All this leaves you with is a plant no taller than around three feet.

I've never SCROGGED but I have applied LST and super-crop techniques in previous grows, so you could implement the 3590s but there is no need for lenses or reflectors, especially if you're tent has reflective material in it, as the space doesn't ask of it with such powerful COBs.

I just went through this myself. Ended up with 4 Vero 29's with and HLG 120.

Less parts than the Vero 18's.

Better spread than 2 COB's. I can't find CXB3590's anyway. Only Mouser for $88.

The other issue is actually finding the damn parts in the first place... CXB3590 4000k, not in stock anywhere....Vero 18 and 29's not in stock either. Everything but the cobs is in stock and available.

Why 4000K for veg? Digikey has 5000K. 4.5% more efficient. Am I missing something?

Jeeyah said:

Why 4000K for veg? Digikey has 5000K. 4.5% more efficient. Am I missing something?

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Veg+flower unit. Also, I'm waiting for version 2.0 vero...or top bin cree...Neither seem available...