BobCajun
Well-Known Member
I ones over 240 are more costly per watt.
Mau5Capades: builds & grow journal
- Thread starter Growmau5
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BobCajun
Well-Known Member
COBs have more intensity than singles, due to the close spacing of the individual "dice". I forget the details of exactly why it's more intense but apparently it is, probably involving overlapping beams. There aren't really any high quality COBs with mixed colors, I don't think. Haven't really seen any. Probably would be more prone to burnout from the different colored dice having slightly different operating current/voltage, making such a COB difficult to drive reliably, I would think.
coreywebster
Well-Known Member
Thanks ttystikk !!
It amazing how many top market LED companies all contradict each other. Sometimes the only way to get to the truth is to ask the guys like you who are not all about the money/sales pitch. That's a shame, but that's the world we live in.
coreywebster
Well-Known Member
Ah Cheers Bob, yeah that makes sense. Looking at all the LEDs that I have been lately I get what you mean, although you can get a lot of spectrums around the same Vs and Ma there's defo no way of having the full mix spectrum in the same range in on chip.
How about canopy penetration? Sounds like you can outperform HPS so you get tighter bottom nugs? That's where I struggle if my plants get over 3 feet or I don't prune the hell out of the low end.
Appreciate your input. Ta
C.W
coreywebster
Well-Known Member
While I'm still logged on I may as well ask, Does anyone have a link to or info themselves on PAR and lux readings at different distances from the lights you have built. It really has got my interest peaked this thread.
Cheers
C.W
Cheers
C.W
BobCajun
Well-Known Member
Well I have noticed less lower leaf drop with cobs than HPS. Lower buds are still fluff after the first foot of canopy though.
SoOLED
Well-Known Member
the white cobs 3k-6k have a very good spectrum. its part of what makes them so great. while cobs are and excellent lighting solution that's not to say you cant grow with anything else, given your budget you can grow some great personal nugs.
SoOLED
Well-Known Member
Shredderthirty
Well-Known Member
i have no idea about using a PC power supply, just gonna stick with two drivers........or may just take two off the panel and drive those 8 and just make another panel, but if i take off 2 cxb on that big heatsink then i'm gonna want to run them a little hotter than the usual 25w each....maybe...
my problem now is not the amount of cobs but trying to get enough amps to run them, right now my room is all on one circuit and i'm trying to figure out how to get on another breaker so i can power all of these lights i want in the room (mars1200 *4amps* for veg, then two p600 *6.2amps* and 18 cxb3590 but looking like i'm gonna take out 2 cobs so really probably gonna be 16cxb *10amps?*) plus a 12000btu A/C *9amps* my vortexS6 *.65amps* and some misc. fans and my co2 regulator.
no empty spots on my breaker either to change anything to different voltage so i think guess my choices are to get rid of some lighting or run some extension cords but sounds like i'm shit outta luck but i got a month or so to figure it all out
SoOLED
Well-Known Member
you need a growers panel/box installed. its not cheap, but its way safer then extension cords.i have no idea about using a PC power supply, just gonna stick with two drivers........or may just take two off the panel and drive those 8 and just make another panel, but if i take off 2 cxb on that big heatsink then i'm gonna want to run them a little hotter than the usual 25w each....maybe...
my problem now is not the amount of cobs but trying to get enough amps to run them, right now my room is all on one circuit and i'm trying to figure out how to get on another breaker so i can power all of these lights i want in the room (mars1200 *4amps* for veg, then two p600 *6.2amps* and 18 cxb3590 but looking like i'm gonna take out 2 cobs so really probably gonna be 16cxb *10amps?*) plus a 12000btu A/C *9amps* my vortexS6 *.65amps* and some misc. fans and my co2 regulator.
no empty spots on my breaker either to change anything to different voltage so i think guess my choices are to get rid of some lighting or run some extension cords but sounds like i'm shit outta luck but i got a month or so to figure it all out
JorgeGonzales
Well-Known Member
Well, here's the thing. I read that as well, but it isn't saying there is any harm between 24-50%, or that the enhanced growth disappeared, is it? I've read other studies that say green light's effect is also related to the R:FR ratio, and compared to the sun all broad spectrum LEDs have very little FR compared to nature. They are using mono leds in different ratios, where the situation is a little more complicated with cobs.
I just broke out the spreadsheet, and grabbed some SPD curves from Nichia cobs, and here's what it looks like. Blue is 400-500nm, Green is 500-600nm, Red is 600-700nm:
"Green" is usually broadly defined as 500-600nm, which of course includes a lot of yellow as well. Does that affect growth negatively? Maybe you should cut the percentages in half to get closer to green percentages like the study you quoted, since a bunch is yellow light. In which case you'd want much more green than you would think!
NFDLJ130B 3000k 80 CRI
NFDLJ130B 5000k 80 CRI
NFDLJ130B 3000k 90 CRI
So yeah, even 3000k 90 CRI has way too much green, maybe, depending on how you interpret the data. That was interesting. @alesh might have already done all of this, I just chose Nichia because they actually have tables of SPD data, so I could skip the digitizing.
My 4000k Citizen at 80 CRI actually looks like this:
And who knows, maybe that is terrible! These really need alesh's Cree data for most people to find it applicable. Maybe some pie charts, and more fine-grained color differentiations, especially between green and yellow. But these are numbers I had close at hand, and I am being lazy.
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ttystikk
Well-Known Member
I run a research and consulting lab, so my credibility is worth a lot more to me than any single product or lineup.
ttystikk
Well-Known Member
Good question and 'no', because PC power supplies aren't current limited. They'll run the risk of frying your COB string.
Unless your trying to improve growth for low light level blue and red in LETTUCE this research is irrelevant.
Especially for production light levels of cannabis. Suggest you pay attention to the umols of light that the researchers are putting on the plants. Especially those that are trying to understand the physiological shade responses.
You can easily tune the amount of green light relative to other wavelengths just by choosing the white phosphor cob that fits what you want.
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pop22
Well-Known Member
Because, those so called "top brands " lights won't match most of the DIY lights for output, and most of those compaines have a big investment into led stockpiles, or contractual obligations to buy x amount. It won't be long before COBs replace most single led applications.
BobCajun
Well-Known Member
Thanks for the figures. Yeah that's way too much green, more than either blue or red, except for the 3000k 90 CRT. A green dominant spectrum is not a desirable thing for me. Others, maybe. I'm not recommending anyone else use filters. I just mentioned that I was personally going to try them. Thought GM5 might find it slightly interesting since nobody else ever did it, at least not that I could find anywhere online. Your figures show that the green problem is worse than I even imagined. Green is out of control.
JorgeGonzales
Well-Known Member
Keep in mind that study used 525 nm leds, not white light. It might not be a problem at all.
Shredderthirty
Well-Known Member
oh man, what's not cheap because the heavy duty cords at a good length are not the cheapest either
SoOLED
Well-Known Member
yeah, and it took me two weeks to tear everything down and clear out of the space, cant have some guy working in your running lab.
I moved from that house awhile ago, I wonder what the new owners thought? a panel breaker and 6 plugs + kw meter in the rec-room they called it.
JorgeGonzales
Well-Known Member
Here is some stuff from @alesh, who is much better at this than I am. Instead of subtracting you could add red or blue to hit whatever ratio you wanted.