Top bin COB comparison
- Thread starter SupraSPL
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cdgmoney250
Well-Known Member
@wietefras
I understand just fine, thanks.
I agree, that depending on the size of the grow space, not using reflectors or lenses would actually only make sense. Small spaces/ cabinets would more than likely not need any optics and would often times have reflective walls because of the nature of the small space.
Now think large scale.
Where there are rows of cannabis and aisles to walk between them. Plants are on average 4-6 ft tall. If you want light pentration deep into the canopy, a form of optics will only help achieve this goal.
More usable light at depth means bigger frostier buds and a higher yield.
Reflecting light off the walls back towards the canopy and decreasing light losses is a good thing. Check. I think we are all in agreement with that.
I like testing lights in the dark to see how the fixture itself performs. No help from anything else.
I understand just fine, thanks.
I agree, that depending on the size of the grow space, not using reflectors or lenses would actually only make sense. Small spaces/ cabinets would more than likely not need any optics and would often times have reflective walls because of the nature of the small space.
Now think large scale.
Where there are rows of cannabis and aisles to walk between them. Plants are on average 4-6 ft tall. If you want light pentration deep into the canopy, a form of optics will only help achieve this goal.
More usable light at depth means bigger frostier buds and a higher yield.
Reflecting light off the walls back towards the canopy and decreasing light losses is a good thing. Check. I think we are all in agreement with that.
I like testing lights in the dark to see how the fixture itself performs. No help from anything else.
cdgmoney250
Well-Known Member
bassman999
Well-Known Member
I know reflectors seem the better choice over lenses, but on paper I liked the KB120 optics.
I have used neither, so my opinion is bearing little weight though.
bassman999
Well-Known Member
I think eventually I will run 1 per ft^2 at 1.4A or thereabouts with dimming potential
cdgmoney250
Well-Known Member
Or add reflectors/lenses and gain 20-30% higher ppfd over desired area...
littlejacob
Well-Known Member
Bonjour
How is penetration @700mA 23/25w?
Do you get 1.5/2ft?
What is the effective penetration for a cxb3590 36V @ 1750/1400/1050 and 700mA should be a good thread!...then compare it with optics at different heights...
Some growers who like looong vegg time add some lights on sides too!
CU
Can you start a new thread with this title.
What is the effective penetration for a cxb3590 36V @ 1750/1400/1050 and 700mA .
I am asking you because is a good idea and is your, I used to do long vegg and because of that I would like to know how tall can the plants be using COB.
Thanks for bringing this up.
EfficientWatt
Well-Known Member
Hard to give a definit answer to that.
It would depend mainly on cob density, bit also plant/canopy density too ...
8 cob ? 9, 12, 16 cob per m² ?
It would depend mainly on cob density, bit also plant/canopy density too ...
8 cob ? 9, 12, 16 cob per m² ?
wietefras
Well-Known Member
Yeah, me too. Or a 50W at 12" per square foot and a half or something.
The surface area depends on the PPFD that you aim for. Lower PPFD for higher g/W and less compact buds, or higher PPFD for lower g/W and harder buds.
wietefras
Well-Known Member
A reflector does not create light.
If you want higher PPFD over the whole area, reflectors do nothing for that. You would need to start with a higher PPF.
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he did not say over the whole area, he said over the desired area. big diff
wow
EfficientWatt
Well-Known Member
Thought the same thing, it's like he's a professional circle walker
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwi7-cjO2ZDKAhVC2mMKHTI1DAkQ3ywIHjAA&url=https://www.youtube.com/watch?v=V9VoLCO-d6U&usg=AFQjCNEE3y9VYNK35FfTKfvzoD-q8O62mQ&sig2=G-lRoea9SqvDiKcIalhHHgThought the same thing, it's like he's a professional circle walker
SupraSPL
Well-Known Member
I use a combination of bare COBs in the center of the canopy and reflectorized COBs on the edge of the canopy. I suspect that if I used short reflectors in the center I could improve gpw.
I do believe reflector losses will be lower than wall losses because the reflector has more opportunities to redirect scattered photons in the right direction, but I have not done any tests to explore that specifically. In addition to reflectors, I use reflective walls wherever possible, as long as it does not interfere with airflow .
When it comes to DIY reflectors, the Rustoleum white heat paint 7751830 was the objective clear winner against about a dozen paints that I tested, including metallic paints that have 10% aluminum flake and paint that used 20% titanium dioxide, which actually appears whiter to the eye than the heat paint. I have no explanation why the heat paint works best, it has 10% titanium dioxide and 5% barium sulphate, apparently there is more to it than that. MSDS.
Dull aluminum was a poor performer but I did not test polished aluminum. Semi gloss and gloss paints performed poorly even with high levels of titanium dioxide. I assume the "gel" layer taxes the photons.
Plain white plastic was a poor performer and improved significantly after being painted and improved significantly again after a second coat. The third coat did not help at all. With 2 coats the material is still translucent but there is no more to be gained by increasing the paint layers. That means that after 2 coats, the photons that penetrated the surface could not make it back out the front side anyway. That is why a third coat cannot help. A small portion of the photons will pass completely through the paint and the plastic, easily visible to our eyes as translucence. The same thing happens when light hits the surface layer of polished aluminum, some of the photons will penetrate but not as deeply as with paint/plastic. If the translucence bothers you can use a black layer to absorb it but to some tiny extent that will unnecessarily increase the temperature near the COB.
Interesting, the heat paint coated reflector slightly improved performance after having earth worm casting smeared on it and then rinsed with plain water. So they are easily cleaned and no harm done, unlike polished aluminum.
I intend to test the Ledil and Ledil knockoff reflectors to see if they improve after being coated with heat paint. If they are made from white plastic with no special coating, I think we can expect a nice improvement. At $0.80 ea for 3590 reflectors there is alot of potential there for DIYers to boost gpw
I do believe reflector losses will be lower than wall losses because the reflector has more opportunities to redirect scattered photons in the right direction, but I have not done any tests to explore that specifically. In addition to reflectors, I use reflective walls wherever possible, as long as it does not interfere with airflow .
When it comes to DIY reflectors, the Rustoleum white heat paint 7751830 was the objective clear winner against about a dozen paints that I tested, including metallic paints that have 10% aluminum flake and paint that used 20% titanium dioxide, which actually appears whiter to the eye than the heat paint. I have no explanation why the heat paint works best, it has 10% titanium dioxide and 5% barium sulphate, apparently there is more to it than that. MSDS.
Dull aluminum was a poor performer but I did not test polished aluminum. Semi gloss and gloss paints performed poorly even with high levels of titanium dioxide. I assume the "gel" layer taxes the photons.
Plain white plastic was a poor performer and improved significantly after being painted and improved significantly again after a second coat. The third coat did not help at all. With 2 coats the material is still translucent but there is no more to be gained by increasing the paint layers. That means that after 2 coats, the photons that penetrated the surface could not make it back out the front side anyway. That is why a third coat cannot help. A small portion of the photons will pass completely through the paint and the plastic, easily visible to our eyes as translucence. The same thing happens when light hits the surface layer of polished aluminum, some of the photons will penetrate but not as deeply as with paint/plastic. If the translucence bothers you can use a black layer to absorb it but to some tiny extent that will unnecessarily increase the temperature near the COB.
Interesting, the heat paint coated reflector slightly improved performance after having earth worm casting smeared on it and then rinsed with plain water. So they are easily cleaned and no harm done, unlike polished aluminum.
I intend to test the Ledil and Ledil knockoff reflectors to see if they improve after being coated with heat paint. If they are made from white plastic with no special coating, I think we can expect a nice improvement. At $0.80 ea for 3590 reflectors there is alot of potential there for DIYers to boost gpw
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wietefras
Well-Known Member
Seriously, you think it makes sense to look for anything else but the PPFD over the whole grow area?Thought the same thing, it's like he's a professional circle walker
BuddyColas
Well-Known Member
No offense, but as a noob, that is the exact formula I used for building my first two light bars. Bare cobs and reflective walls in a grow box...and it works really well. The jury is not in yet on my first cob yield (as in dry bud on scales), but from many previous HPS grows the yield is going to be good from these cobs with a fairly uniform 700 umols across the canopy. Simple is good for a noob!
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