DIY COB reflectors

Greengenes707 said:

If a reflector is 90% and so is a reflective wall...is there a difference?
That is my point with small areas.

In the end it doesn't matter what you use as long as you meet the plants requirements. These light requirements are not new or specific to any lighting. Light is light.
I have been using led well before cobs and know quite well what lenses can do. And how they can step up intensity...but it's still all the same PPF assuming similar efficiencies. Reflectors are probably the most under studied in our industry. And personally think that is the best option for harnessing the PPF into PPFD while still meeting the whole canopies requirements and minimizing photon losses.

If cobs lacked intensity I would be all over lenses...but they don't. I don't need more intensity...just a little cleaning up/wrangling around the edges.

Click to expand...

This is almost exactly how I feel except I didn't have to type it all out!

Greengenes707 said:

Where did I say diffusion over proper intensity???
Read again. I'm sick of repeating my self and coming off hostile...but truthfully am getting there. Do what ever you guys want to but please document and show it all. Not just one person who would be successful with a candle if he wanted to(supra). More of you need to start contributing to mass info if you really want things to progress. Not just get one piece for me be source and regurgitate it a day later as if you have know it for years.

I'll be in my own thread occasionally...but it is time to take a big hiatus from this place.

Light is light and what plants want is what plants want. Give it to them with what makes it best...then get high.

Peace out gentleman!

Click to expand...

Yes, contributions from all sides would certainly make this process more enjoyable.

I was thinking about it a moment or two ago... what is the limit of light that we can provide our plants with? What is the ideal, besides the sun? Is it only theoretical with what technology we have or is there some set formula that maximizes how much a plant can produce, with respect only to light? I understand getting over one gram per watt used is considered exceptional but I mean, what the hell is the limit here?

I could be babbling but this question crossed my mind earlier when discussing the uses of reflectors and lenses but because we are all here, striving to harvest bountiful crops, figured I'd throw it in.

I don't see how it's anything like the vertical vs traditional canopy debate. Most commercial grow tents have stock heights that you will have to work with. If I was growing in an open room, I would probably be using big cobs with reflectors, mostly out of ease. The low profile design would still work with a tall open room, but not the other way around. I had a big problem using vero 29 effectively in a 4'x2' tent. The middle gets cooked if it gets too tall.

The reason I want a low profile light is out of design requirements. It was never my intention to convert a bedroom into a giant grow operation. 4'x2' tents are usually about 5.5 feet tall, and with the amount of 4x2 tents on the market, I practically see that height as a standard dimension. I'm designing specifically around those requirements.

Never did I say that small tent growing is better than open room growing. It's completely different design requirements.

AquariusPanta said:

Yes, contributions from all sides would certainly make this process more enjoyable.

I was thinking about it a moment or two ago... what is the limit of light that we can provide our plants with? What is the ideal, besides the sun? Is it only theoretical with what technology we have or is there some set formula that maximizes how much a plant can produce, with respect only to light? I understand getting over one gram per watt used is considered exceptional but I mean, what the hell is the limit here?

I could be babbling but this question crossed my mind earlier when discussing the uses of reflectors and lenses but because we are all here, striving to harvest bountiful crops, figured I'd throw it in.

Click to expand...

With all do respect...you just made my case and point. Search more ask less.
I posted all the links in the vero thread literally just yesterday when talking about green light.
And they were all originally from way(years) before.

@Greengenes707 I didnt put any words in your mouth, and i was just trying to get clear info, not argue. ill just dropp of the threads now since trying to ask questions and understand results ends in hostility lol. you should understand if newbs didnt talk theyd never learn. and if you state youve done a test and someone asks for the result, dont flame. that was kinda the whole point of the thread is results. not bs liek this.. info that coulda maybe have been derived if civil convo exists may include, but not limited to, if you diffuse does tha tmena you need to start with a higher intesnity output if you plan to diffuse your lights in your grow area what spacing. all sort of shit that isnt on here now, I was gathering clear concise info for a newbie guide cause all the info you guys kick around in here gets lost in bs like this, and we force people to read. to each thier own. deuces.

Greengenes707 said:

If a reflector is 90% and so is a reflective wall...is there a difference?
That is my point with small areas.

In the end it doesn't matter what you use as long as you meet the plants requirements. These light requirements are not new or specific to any lighting. Light is light.
I have been using led well before cobs and know quite well what lenses can do. And how they can step up intensity...but it's still all the same PPF assuming similar efficiencies. Reflectors are probably the most under studied in our industry. And personally think that is the best option for harnessing the PPF into PPFD while still meeting the whole canopies requirements and minimizing photon losses.

If cobs lacked intensity I would be all over lenses...but they don't. I don't need more intensity...just a little cleaning up/wrangling around the edges.

Click to expand...

I agree, again
I can't see a point of using lenses and/or reflectors in a reflective tent. Bare COBs will probably have more even distribution of light, it will be more diffused and reaching deeper into the canopy.
On the other hand, in large open spaces, especially when the light are not intended to be height-adjustable, lenses/reflectors will probably be beneficial.

There's also one important point for using lenses/reflectors in commercial lights - they provide an enclosure for the COB and it's LES is not directly exposed to the environment.

Greengenes707 said:

With all do respect...you just made my case and point. Search more ask less.
I posted all the links in the vero thread literally just yesterday when talking about green light.
And they were all originally from way(years) before.

Click to expand...

Ehh it was merely a thought-provoking, open-ended question....

Not a "what is 30 x .700 ' question...

I wasn't looking for an answer.... but you missed the point because you like to flap around and fuss when you get bored with matters. Those links you threw up on the vero thread were beneficial for the community, so I thank you for refreshing those URLs; if someone didn't occasionally kick up old dirt, then those links would eventually get lost in the vortex that which is the internet. Unfortunately, those links don't encompass EVERY factor that we currently have access to as DIY growers, so I don't know why you brought that up .

Lighterfighter said:

@Greengenes707 I didnt put any words in your mouth, and i was just trying to get clear info, not argue. ill just dropp of the threads now since trying to ask questions and understand results ends in hostility lol. you should understand if newbs didnt talk theyd never learn. and if you state youve done a test and someone asks for the result, dont flame. that was kinda the whole point of the thread is results. not bs liek this.. info that coulda maybe have been derived if civil convo exists may include, but not limited to, if you diffuse does tha tmena you need to start with a higher intesnity output if you plan to diffuse your lights in your grow area what spacing. all sort of shit that isnt on here now, I was gathering clear concise info for a newbie guide cause all the info you guys kick around in here gets lost in bs like this, and we force people to read. to each thier own. deuces.

Click to expand...

Naw, that's really just Ggenes707; 75% of the time he comes off as 'prickish' but he's really not, he just has been around for too many years and for some reason, the weed he's growing apparently ain't helping. He knows his craft though.

I do enjoy arguing with him, even when I'm destined to lose...

Borrowing from the optic lighting design, I have an idea of how to mount the lenses in an easy non drill way. Of course it involves kapton tape. Secure 4 magnets around the COB and the steel lens holder will stick to it and your done. That would allow for easy alignment, easy removal for cleaning the lens and COB and we could swap out different degree reflectors. We could control the distance between the COB and lens by the thickness of the magnet and maybe add magnets .

This heatsink has a steel frame and the optic style magnet setup fits is perfectly and leaves a nice gap between the lens and COB, but not too much of a gap that it tightens the beam.

So this inspired me to do some more testing with the criteria of 35W/ft² and no reflective wall assistance. So I set up the CXA3070 3K Z4 bin at 1.45A, pictured above. Pulsed measurements, COB at Tj 25C.

Glass lens, 10" distance from COB to target I get an 18" light circle, dim edges. But if we just work within the 15" circle of light, that gives us 35W/ft².
Center: 72700 (brighter than my direct afternoon winter sun measurement of 50000 lux or 925 PPFD),
7" off center: 28000 (with sensor tilted toward the light)
7" off center: 16500 lux (sensor flat and partially shadowed)

So I swapped it with my best reflector, kept the same 10" distance from COB to target and I get about 22-23" light circle, not well defined. Working with the same 15" circle:
Center: 45000 lux in the center
7" off center: 30000 lux (sensor tilted)
7" off center: 20000 lux (sensor flat)

So to get a more fair test of the reflector and maintain 35W/ft² I would have to move the COB closer. At 8" distance from COB to target, I get the loosely defined 18" circle, with a 15" circle I can work in:
Center: 73200 lux
7" off center: 30000 lux (sensor tilted)
7" off center: 17600 lux (sensor flat)

And finally bare COB at the 8" distance there is no defined light circle.
Center: 46000
7" off center 24500 lux (sensor tilted)
7" off center 14000 (sensor flat).

Moving the bare COB closer, 7" distance there is no defined light circle.
Center lux 62500
7" off center 24000 (sensor tilted)
7" off center 13500 (sensor flat)

I tried going to 6", but the meter malfunctions when taking a center measurement, showing lower readings as I approach the center. Not because of the intensity but I suspect because of the unevenness of light on the sensor surface.

Admittedly, there is some slop in the "sensor tilted" measurements because it changes the distance and the angle of the tilt is inconsistent, but judging by the flat measurements it seems that the reflector outperformed the lens slightly once I adjusted the distance to match the light circle. The results also show that the reflector outperformed the bare COB, but not hugely once we adjusted the distance closer. Finally, I think the results highlight how critical the distance from COB to canopy is to maintain intensity. The distance adjustments were not accounted for in my previous tests and so I think this data is more useful and makes more sense as well which is a relief.

SupraSPL said:

Partially borrowing from the optic lighting design, I have an idea of how to mount the lenses in an easy non drill way. Of course it involves kapton tape. Secure 4 magnets around the COB and the steel lens holder will stick to it and your done. That would allow for easy alignment, easy removal for cleaning the lens and COB and we could swap out different degree reflectors. We could control the distance between the COB and lens by the thickness of the magnet and maybe add magnets .

This heatsink has a steel frame and the optic style magnet setup fits is perfectly and leaves a nice gap between the lens and COB, but not too much of a gap that it tightens the beam.
View attachment 3359778 View attachment 3359779

Click to expand...

"I'm sorry Dave, I'm afraid I can't do that"

(Your photo of the COB w/ lenses gave me a flashback)

After reading your test results between reflector and lenses, it's apparent that lenses are definitely going to center any light output, where the reflector sort of evenly distributes it within the circle it creates. I personally favor the latter outcome.

Can I ask what degrees the reflector and lenses are rated at?

AquariusPanta said:

Naw, that's really just Ggenes707; 75% of the time he comes off as 'prickish' but he's really not, he just has been around for too many years and for some reason, the weed he's growing apparently ain't helping. He knows his craft though.

I do enjoy arguing with him, even when I'm destined to lose...

Click to expand...

AquariusPanta said:

Ehh it was merely a thought-provoking, open-ended question....

Not a "what is 30 x .700 ' question...

I wasn't looking for an answer.... but you missed the point because you like to flap around and fuss when you get bored with matters. Those links you threw up on the vero thread were beneficial for the community, so I thank you for refreshing those URLs; if someone didn't occasionally kick up old dirt, then those links would eventually get lost in the vortex that which is the internet. Unfortunately, those links don't encompass EVERY factor that we currently have access to as DIY growers, so I don't know why you brought that up .

Click to expand...

Do you have a specific something they are not encompassing?

https://www.rollitup.org/t/photosynthesis-under-solid-state-light-setting-the-standards.833449/page-1

https://www.rollitup.org/t/cree-cxa-3000k-80cri-spectrum-analysis.832666/

If those two don't have basically everything you need then you have moved well beyond this forum. Or at least narrow you down to a specific question, not just "I wonder..." Then get pissed I give you a easily findable answer.
P.s. The links are by one of your diy crushes.

Now let's get back to who is being a prick here...
Tightpocket(not you two) asked about 4 cxa's at 1.4 in a 2x2(50+watts/sqft). I gave an educated and empirically backed recomemdation. You two self proclaimed noobs(though you seem to think your experts till called out)that like to make thread to educate people on tech you just found days before...try and dispute my recommendation based on your feelings and own random trains of thought you had. You try to find loopholes and situations that aren't even in the context just to try and prove me wrong for some reason. So you want him to put lenses in in a 2x2 situation with 50+w/sqft in there???
Call it prickish all you want....but show me where I have showed or said something not backed by my own testing, or a scientific study?
You guys come one here one day and discover led greatness through someone else's eyes, the next day your an expert starting threads about it a marketing recommendations to people based off what expirience? Then all of a sudden when someone gets sick of guesses and hypothesis and gives you data and experience...it's prickish.
So who is really halting progress fanboys?

Another thing that may be skewing the results slightly, because of the reflectivity of the wall, reflectivity and size of the reflector, some light hitting the wall is bouncing back to the reflector and then back again to the sensor. So once in the canopy that effect would be reduced because the canopy is not as refelcive as the wall. So the reflector results are slightly skewed in its favor but probably no biggy and it might be helpful in the canopy as well.

See how close 8" distance is in practice. Definitely some re-reflection going on that will not occur when using lenses. Edit: Just measured it, Wow 16000 lux bouncing back off that wall at the edge of the reflector.

AP the lense is supposed to be a 90 degree, but must be wider in practice since I am getting a 15-18" light circle at 10" distance. I consider that a good thing I wold prefer wider than 90 degrees in a lens for my setup.

The reflector is from a 2 liter soda bottle, which appears to start off at a 90 degree angle and then tighten up to maybe 60 degrees. That should lead to an even tighter beam, smaller circle and longer distance to canopy, but in practice it creates an even larger circle, probably because of the scattering effect of the white paint.

Greengenes707 said:

Do you have a specific something they are not encompassing?

https://www.rollitup.org/t/photosynthesis-under-solid-state-light-setting-the-standards.833449/page-1

https://www.rollitup.org/t/cree-cxa-3000k-80cri-spectrum-analysis.832666/

If those two don't have basically everything you need then you have moved well beyond this forum. Or at least narrow you down to a specific question, not just "I wonder..." Then get pissed I give you a easily findable answer.
P.s. The links are by one of your diy crushes.

Now let's get back to who is being a prick here...
Tightpocket(not you two) asked about 4 cxa's at 1.4 in a 2x2(50+watts/sqft). I gave an educated and empirically backed recomemdation. You two self proclaimed noobs(though you seem to think your experts till called out)that like to make thread to educate people on tech you just found days before...try and dispute my recommendation based on your feelings and own random trains of thought you had. You try to find loopholes and situations that aren't even in the context just to try and prove me wrong for some reason. So you want him to put lenses in in a 2x2 situation with 50+w/sqft in there???
Call it prickish all you want....but show me where I have showed or said something not backed by my own testing, or a scientific study?
You guys come one here one day and discover led greatness through someone else's eyes, the next day your an expert starting threads about it a marketing recommendations to people based off what expirience? Then all of a sudden when someone gets sick of guesses and hypothesis and gives you data and experience...it's prickish.
So who is really halting progress fanboys?

Click to expand...

DIY crush? LOL, now that is rich. He is one my idols here on RIU, make no doubt about it.

Those links you share DO shed light on answering my question, I just didn't take the time to read through it all, as those threads are fairly new to me and the material isn't as intuitive as one might like it to be.

Listen, if you don't enjoy rehashing old threads (which is understandable) then don't rehash. Just move on with your life or something. Don't get pissed off at us because we didn't know these threads existed, otherwise wouldn't you think we would go look for them ourselves? Obviously some of us are lazy about digging up old material but not all of us. Give us the benefit of doubt, mate.

I was unaware of disputing your recommendation/advice.. I personally know that I'm in no stance to challenge your knowledge of reflectors and lenses. So you perceived my comments incorrectly, sorry. I do like to argue with you from time to time (as you are surely aware), it's just the character you carry with you but I did not intentionally try to slander your advice to tightpocket. I'm actually a little bewildered from your accusation...

"You guys come one here one day and discover led greatness through someone else's eyes"

Isn't that how technology and the progression of human innovation works? One guy invents the wheel, the next guy the steering wheel, and the next guy the engine? But eventually, everything becomes known and before you know it, you're living in a world that has no mystery to it and all you can do is learn about some person's past discoveries (ooops, I've said too much).

See how I stated 75% of the time you come off as prickish, while the other 25% of the time you are informative and share knowledge but usually only after arguing with you or someone not understanding, such as @hyroot in the Vero thread. I believe if you were a little more understanding and patient with certain individuals, then I wouldn't get that impression but that's just my perception, which carries with it error.

You are right about my ego trip with COBs but I'm not quite sure about your claim on making threads on technology we just came about. I can only assume you are directing that statement towards the Vero thread I created. Ok, so I was a little excited that I could USE MY UNDERSTANDING OF EXCEL to create something that Supra has done in the past. I was happy that I could come CLOSE to replicating something one of the DIY superstars of this forum had provided others.

"Do what ever you guys want to but please document and show it all. Not just one person who would be successful with a candle if he wanted to(supra). More of you need to start contributing to mass info if you really want things to progress"

Sound familiar?

I think my man g is just being straight up. He's a straight up guy,Always helpful and insightful, and always cool about it I'm just chalking it up as you rubbed the magic lamp the wrong way. He's probably sick of the ppl coming in and acting like they found it all when they found it here. Gs my boy I have his back every day of the week and he's right on so many levels. Someone said "led experts" the other day and insinuated that I was apart of that group- IM not. Literally everything I've learned about LEDS has been from this subforum and the fellow forum runners that are apart of it. I was rocking PRO GROWS when I came in here a few years ago. Wtf?! I an guilty of regurgitating what I'm told but I do not take the fame for it. I meant to reply to that post and let some ppl know that my "knowledge" goes out to supe, flux, sds, franjan, pos, g, solomon, guod, chaz, Pico and a few others. I am constantly thanking them for their efforts and try to give back with readings/charts where I can and take some of the heat off of them when a newcomer asks a question I know the answer to. These guys rock. I'm surprised I haven't asked supra to go ahead and marry my fiance and I in July. Lol.

Just squash it, give credit where due and take in everything you can. Just remember where you got it.

Again my hats off to all my FRIENDS out there.

Not everything is at you @AquariusPanta, but glad your catching some things.
I don't really care about feelings when I see something put forth as fact when the actual data is supporting differently.
As for hyroot...search in the RIU bar "green light" and put his name in the by who part...
He has cited a study multiple times for a couple years now. That study clearly concludes with a high amount of green light being usable to photosynthesis.
And I was blown away that he more or less has switched his stance on the subject.
And just like you, he did not actually read what was linked, or even what he linked, just started disputing based on???

I am here to learn more than most anyone and used to a lot. But now am only finding people preaching without expirience or support of their own claims. And that there is very little progression actually taking place.
SDS and guod have put me in my place many times over the years, and I take it...learn my mistakes...and then keep learning it till there is not grey area left.

And @SupraSPL... That you for everything you do. I don't dissagree or question any of your tested data. Keep it coming as usual.
My problem is how they take the data and apply it to in use/final system performce.
Sorry to get this thread into this mood...but it had to be done.

I think the main issue is people acting like the authority on the subject before even reading through many threads here. A day after aquarius learned what efficiency was, "All things vero" popped up.

But the "cbx" thread??? Can you please let Supra or SDS, or GG or aquarius (after he reads those 2 threads), or anyone who has read the threads GG posted.

https://www.rollitup.org/t/photosynthesis-under-solid-state-light-setting-the-standards.833449/page-1

https://www.rollitup.org/t/cree-cxa-3000k-80cri-spectrum-analysis.832666/

You really should have read those 2 threads before making a general information thread!!

Anyway, reflectors and lenses are cool!!

I've been guilty of assuming authority over subjects before doing my homework. It's not an effective stance to take in most cases but can be used to learn, at the cost of credibility and reputation.

Lol @churchhaze why should have I read those two threads before making a quasi-general informational thread? Go ahead, everyone take a turn at rubbing my face in the dirt ... you too Supra . Mmmm, are those worms that I taste?

The Vero thread was created in order to bring people's experiences of the Vero lineup, including mine, into one thread, not to showcase what I do and don't know.

SupraSPL said:

So this inspired me to do some more testing with the criteria of 35W/ft² and no reflective wall assistance. So I set up the CXA3070 3K Z4 bin at 1.45A, pictured above. Pulsed measurements, COB at Tj 25C.

Glass lens, 10" distance from COB to target I get an 18" light circle, dim edges. But if we just work within the 15" circle of light, that gives us 35W/ft².
Center: 72700 (brighter than my direct afternoon winter sun measurement of 50000 lux or 925 PPFD),
7" off center: 28000 (with sensor tilted toward the light)
7" off center: 16500 lux (sensor flat and partially shadowed)

So I swapped it with my best reflector, kept the same 10" distance from COB to target and I get about 22-23" light circle, not well defined. Working with the same 15" circle:
Center: 45000 lux in the center
7" off center: 30000 lux (sensor tilted)
7" off center: 20000 lux (sensor flat)

So to get a more fair test of the reflector and maintain 35W/ft² I would have to move the COB closer. At 8" distance from COB to target, I get the loosely defined 18" circle, with a 15" circle I can work in:
Center: 73200 lux
7" off center: 30000 lux (sensor tilted)
7" off center: 17600 lux (sensor flat)

And finally bare COB at the 8" distance there is no defined light circle.
Center: 46000
7" off center 24500 lux (sensor tilted)
7" off center 14000 (sensor flat).

Moving the bare COB closer, 7" distance there is no defined light circle.
Center lux 62500
7" off center 24000 (sensor tilted)
7" off center 13500 (sensor flat)

I tried going to 6", but the meter malfunctions when taking a center measurement, showing lower readings as I approach the center. Not because of the intensity but I suspect because of the unevenness of light on the sensor surface.

Admittedly, there is some slop in the "sensor tilted" measurements because it changes the distance and the angle of the tilt is inconsistent, but judging by the flat measurements it seems that the reflector outperformed the lens slightly once I adjusted the distance to match the light circle. The results also show that the reflector outperformed the bare COB, but not hugely once we adjusted the distance closer. Finally, I think the results highlight how critical the distance from COB to canopy is to maintain intensity. The distance adjustments were not accounted for in my previous tests and so I think this data is more useful and makes more sense as well which is a relief.

Click to expand...

I think this makes sense as someone pointed out earlier lenses can't "add" light they can only focus it. That being said, the amount of light focused in the same diameter circle should be roughly the same. These findings are especially useful to me because my armoir is 42"x18" so now I know where the sweet spot is distance wise..thanks!