DIY COB reflectors

All that's great ..Really .

Still ....


https://ag.arizona.edu/ceac/sites/ag.arizona.edu.ceac/files/10 R. Hernandez Plant Lighting.pdf

I just don't know what to think some times, first one thing and then another.

just stumbled across this; it claims to be very reflective and very diffused....thought it might be of interest to some of you,

http://www2.dupont.com/Diffuse_Light_Reflectors/en_US/assets/downloads/NOW801_DLR_Sell_Sheet_me05-21.pdf

Good info UKP. It says available in molded parts licenses to white optics, I will check into it.

Interesting post from Beta Test Team in IC. Something I have been howling about for some time, when a manufacturer claims 96% reflectivity here is how that translates for HPS:

Greenbeams with Philips Green Power CMH 315W
-- Greenbeams reflective material reflectivity, according to Cycloptics: 95%
-- Relative amount photons emitted by the lamp that exit the reflector after a single bounce, according to Cycloptics: 95%
-- Relative amount of photons emitted by the lamp that exit the reflector, according to Cycloptics: 92.3%
-- Relative amount of photosynthetic photons emitted by the lamp (400-700nm) that exit the reflector: 76.84%
-- Reduction in photosynthetic photons (400-700nm) exiting the reflector as compared to emitted by the lamp: 23.16%

Gavita PRO DE HPS 1000W
-- Gavita 'HortiStar' reflective material reflectivity, according to Gavita: 96%
-- Relative amount photons emitted by the lamp that exit the reflector after a single bounce: unknown
-- Relative amount of photons emitted by the lamp that exit the reflector: unknown
-- Relative amount of photosynthetic photons emitted by the lamp (400-700nm) that exit the reflector: 80.95%
-- Reduction in photosynthetic photons (400-700nm) exiting the reflector as compared to emitted by the lamp: 19%

Reality check on reflectance/reflectivity ==== don't take any seller's word as gospel

Bare bulb vert looks even more appealing now...............only way to fly imo

And these HID reflectors^^^ are also very high quality..........hate to see the #s on the cheap/generic ones!yikes

@medicinehuman found a great deal on large lenses:

http://www.lck-led.com/degree-67mm-convex-lens-edges-opitc-100w-p-765.html?cPath=157

They dont have mounting holes but should be a good size for CXA3070s, CXA3590 and Vero29s. Good find!

10% discount code: cpfer

SupraSPL said:

@medicinehuman found a great deal on large lenses:

http://www.lck-led.com/degree-67mm-convex-lens-edges-opitc-100w-p-765.html?cPath=157

They dont have mounting holes but should be a good size for CXA3070s, CXA3590 and Vero29s. Good find!

10% discount code: cpfer

Click to expand...

you think a lens would be a better option instead of some sort of reflector? I like the focus idea, but more glass in the light path is a loss too. Might be time for a test

Nice 50° reflector for CXA3050/3070. Should be about 89% efficient which is not bad. I'm sure how to mount it, though.
http://en.bicomoptics.com/Productshow.asp?BigClassID=443&SmallClassID=482&Pid=1408&ProClassID=483

Available at AliEx directly from the manufacturer (!). Sweet price for larger offers (>about 20).
http://www.aliexpress.com/store/product/CITIZEN-CLL040-OSRAM-E45-Reflectors-with-77mm-Diameter-about-45-degrees-PC-materials-Model-No-BK/413107_670064214.html

This question may be naieve; and I have to admit that I didn't read through the entire thread - sorry about that, but here goes.

Aren't LED's directional to begin with? Don't they shoot light out in a pre-determined beam? If so, wouldn't that make a reflector redundant?

I'm not trying to piss anybody off, just looking for some edu-ma-cation!

Awesome find thnx @alesh

All good thcammo, I though the same thing but here is what the output of a bare Vero 29 looks like. The COB is pointing at the ceiling, this is the side view. I tried hard to get the exposure to match what my eyes were seeing and I think this is a good representation.



This is a pair of Vero 18s side by side, 16" away from the wall, pointing directly at the wall. One has a lens attached and one is bare. The increase in intensity is 200-300% in the entire footprint. Again it was hard to get the exposure correct because the camera does not have the dynamic range that our eyes do and this picture slightly understates the dim side. But the lux meter numbers show an amazing increase in intensity, more than any reflector I have tried yet. I was not expecting that I figured lenses would be a flop. It took some time and several test results before I could accept it. There are smart DIYers that remain unconvinced, so this is currently a controversial idea.

SupraSPL said:

Awesome find thnx @alesh

All good thcammo, I though the same thing but here is what the output of a bare Vero 29 looks like. The COB is pointing at the ceiling, this is the side view. I tried hard to get the exposure to match what my eyes were seeing and I think this is a good representation.



This is a pair of Vero 18s side by side, 16" away from the wall, pointing directly at the wall. One has a lens attached and one is bare. The increase in intensity is 200-300% in the entire footprint. Again it was hard to get the exposure correct because the camera does not have the dynamic range that our eyes do and this picture slightly understates the dim side. But the lux meter numbers show an amazing increase in intensity, more than any reflector I have tried yet. I was not expecting that I figured lenses would be a flop. It took some time and several test results before I could accept it. There are smart DIYers that remain unconvinced, so this is currently a controversial idea.
View attachment 3354650

Click to expand...

What is the diameter of the hotspot?

Okay, so what i'm seeing is a light pattern something like a "Fried Egg". Where the brightly lit spot in the center is the "Yoke" and the hazy area created by stray light would be the "Egg White".

Are you trying to re-direct that "stray light", so that it all lands inside the "Yoke"? Sorry about my fried egg terminology! Anyway, if that's what you are doing it all makes perfect sense now. Thanks for the demonstration!

Yes that is exactly right.

Alesh, do you mean the hot spot in the second pic? At a distance from the wall of 16", the diameter of the well lit area is about 17".

I did some 12" testing with and without the 90* ledil reflector. Results were great and pretty much right inline with what I expected to see.

With the 90* reflector


Bare COB





The µmol results for what would be an 18" diameter coverage...

Greengenes707 said:

I did some 12" testing with and without the 90* ledil reflector. Results were great and pretty much right inline with what I expected to see.

With the 90* reflector
View attachment 3356692

Bare COB
View attachment 3356693




The µmol results for what would be an 18" diameter coverage...
View attachment 3356689

Click to expand...

Thanks! Would you be able to do one more measurement at 12" off center as that would give all points within the 90deg light cone.

Awesome data GG !! Apparently that is a darn good reflector too. How high do you normally run 50W CXA3070s from the canopy?

draz said:

Thanks! Would you be able to do one more measurement at 12" off center as that would give all points within the 90deg light cone.

Click to expand...

It was about 110µmols with the reflector on. I didn't do it with it off and now it has been moved around. But I'll try to get one later for reference. The reason I didn't was because at 9" I was at the limit I wanted to see for intensity.

SupraSPL said:

Awesome data GG !! Apparently that is a darn good reflector too. How high do you normally run 50W CXA3070s from the canopy?

Click to expand...

They are 94% efficient reflective. I assume a portion of light never uses the reflector so loss is limited. Plus they are AD's instead of AB's.
I have been running AB's in flower anywhere from 8"-14" with the drone, it's so spread out. The bigger bare cxa panel at
~18" and getting 900µmols...and >700µmols almost everywhere. The 90 reflectors are perfect for bigger panels. I need more holders so I can put them on mine.
Smaller panels/designs could use tighter 78* reflectors that could boost numbers closer to lens like numbers. Most lenses are tighter than 90* anyways. But the 90*'s reflectors have my pick for my needs.

Awesome, at that distance I expect you will see big increase in gpw with the reflectors. I put some on my vegging CXA3590s and so far amazing difference.