Are cobs worth it?

[Hybridway]

wow you really are in denial. did you even fucking read it?

Hids are designed to block the most dangerous UVC and UVB rays. its designed that way for human safety.

Sure thing. But fact remains, they still emit more then a little bit.
I read it but know more from actual experience. Believe everything you read & you'll never know anything from experience & will continue to be a data-sheet zombie who does NOT grow but tells everyone he knows everything.
I see from using my MH Hotrilux Daylight Blues & others, the direct effects of UV on my bud. You know, the big things on plants most of us grow here & talk about, then smoke.

 

[churchhaze]

Is there even strong conclusive evidence that UV-B produces more THC while UV-A, violet or blue will not? I keep hearing "UV-B, not UV-A", but I wonder how much either really matters.

 

[PurpleBuz]

Sure thing. But fact remains, they still emit more then a little bit.
I read it but know more from actual experience. Believe everything you read & you'll never know anything from experience & will continue to be a data-sheet zombie who does NOT grow but tells everyone he knows everything.
I see from using my MH Hotrilux Daylight Blues & others, the direct effects of UV on my bud. You know, the big things on plants most of us grow here & talk about, then smoke.

that's UVA and actinic blues giving the effect you are seeing. I know I get the same thing supplementing all sorts of leds with actinic aquarium T5s, UVA leds and leds in the 420nm range. frost and color enhancement.

But its NOT UVC or UVB.

 

[sixstring2112]

uv baby,quartz rocks !! http://solis-tek.com/products/lamps-double-ended/solistek-1000w-mh-10k-finisher-de-lamp.html
i use a few in every other fixture and i can say i can def feel the burn through my shirt just like being outside today(my back is fried from working in the sun all day saturday and sunday) plants seem to love em as well.

 

[Hybridway]

Is there even strong conclusive evidence that UV-B produces more THC while UV-A, violet or blue will not? I keep hearing "UV-B, not UV-A", but I wonder how much either really matters.

UVA & UVB both increase potency.
Studies show a consistent 3-5%.
If you try a Hotrilux Blue you will see it apparently by eye. Same with CMH.
Or try a reptile bulb producing UVB.
Using both together will give you the best results. UVC is not good.

 

[Mathematix]

Link for guod's post...
http://www.cree.com/~/media/Files/Cree/LED-Components-and-Modules/XLamp/XLamp-Reference-Designs/HorticultureReferenceDesign.pdf?la=en


From a quick read through, it's very solid and info packed for anyone to dissect. I talked with one of their reps at lightfair and he referenced this, but tried to downplay it. Now I see they were putting a good amount into it.

am i reading this right? are they running those leds at 1050ma?

 

[Hybridway]

I think COBs are worth growing with but not worth all the fuss they get. They still have a ways to go to be far superior to diodes as at the moment more can be done with diodes to achieve differant desired results. Diodes allow more spectral options, are just as efficient for the most part & allow more intensity. Using them together though is the very best option when using LED w/ current technology as is today that we know of.
But they're easier to build & cheaper to buy.
The combination of the 2 should be a better option then HPS. But COBs alone are seriously lacking in results recorded. I hear allot about over 1 GPW but don't see it.
I do see however, tons of side by sides with white COBs yielding the same as HPS but w/o all the heat & venting, hense saving in extra electricity needed for cooling.
I know that is upsetting to hear but I'm not saying it's fact, just that's what I see most.
Where are all these 1.5-2 GPW grows? And it means allot more to see them side by side vs. HPS w/ the same grower & everything else to be valid in being used to compare.

 

[Joegrowsalot]

Getting them for free would be great....but the issue would be getting to where I live in the deep south!

Road trip !!!!

 

[BOBBY_G]

Is there even strong conclusive evidence that UV-B produces more THC while UV-A, violet or blue will not? I keep hearing "UV-B, not UV-A", but I wonder how much either really matters.

sure is

https://silassativariusdotorg2.files.wordpress.com/2016/01/uvb-effects-on-photosynthesis-growth-and-cannabinoid-produciton-in-cannabis-sativa.pdf

 

[BOBBY_G]

View attachment 3713925

wow nice find. They reference "XPGDWT-01-0000-00L5E" which is top bin (S4) per datasheet. digikey has those XPE-G3 chips at just under a buck (much cheaper im sure for those buying a million to build arrays) so assuming a 3590 is $50 "retail" (just to be apples to apples) it appears to be cost competitive with the cobs (about a buck a watt for both at 190 lm/W, but at the 150 lm/W they would get from the XP-G3s @ 1050mA setup in that study, the XP-G3s would be $0.32/W, the cobs would be $0.49/W

perhaps @welight could chime in on a realistic cost for these top bin XP-G3 and if those numbers above make sense. or even better get us some solderless triple stars in the queue

S4 appears to be the equivalent of DB bin, only available from 3700K and up. theyve even got an S5 for the high colors 5700K and up

heres that chip next to 3590 DB in PCT. think of the superior dissipation vs a cob as well

 

[bottletoke]

Curious what a diy cob kit that would cover the same area as 1000w hps would cost?
I wanna try a diy kit out but the sites aren't noob friendly and they dont offer any info on coverage.

 

[BOBBY_G]

i just cant wrap my head around pg 16 of that study

ok i see that the cree design edges the gavita in PPF/W at 1.82 vs 1.72, less than 10% better

so how in the heck do they replace the PPFD of 1000W with only 500W of LED?

what am i missing here? i could see if they were comparing lumens to PPFD or something and heavily weighting the better spectrum but going from PPF to PPFD should be a straightforward application without spectral bias (unless the gavita is throwing 50% of its light outside of the 4x4 and they dont count it? which aint a fair fight in an overlapping warehouse scenario)

 

[BOBBY_G]

Curious what a diy cob kit that would cover the same area as 1000w hps would cost?
I wanna try a diy kit out but the sites aren't noob friendly and they dont offer any info on coverage.

diy is about $2/W and youd need 600W so $1200

 

[bottletoke]

Is one site better to buy at then others?

 

[BOBBY_G]

am i reading this right? are they running those leds at 1050ma?

yes unless theyre running them in parallel. 1050 would make sense as that would be 3.141W per chip (eat that pi, mathematix ) would be 452 W of white. and the reds would likely be driven in parallel at 1.3W ea (62W ea) as 1050 is off their scale and the wattage wouldnt add up

 

[BOBBY_G]

Is one site better to buy at then others?

do you want to piece it together or do you want it all in one kit?

 

[coreywebster]

Is one site better to buy at then others?

Cutter.au have a good kit with reasonable price. Everything is drilled and tapped so you just need a screwdriver
Kingbright on Alibaba have great prices if you dont mind doing business on there. $47 for the cxb3590 with ideal holder, thermal graphite pad and the reflector (which I cant remember the exact name of) or $50.5 for the cxb3590 with ideal holder and glass lens. They also sell the pin heat sinks to match. Where they may not be as good as cutter would probably be the selection on binning, I'm sure others will know more on that.
Cutter state top bins only, they also are really good with delivery prices.
As to coverage it seems some go with one Cob per square foot. Others will again know more than me on that as I don't have any, just going off research and what others are building/using.
If you went with kingbright you would need drivers to match and aluminium L shaped to join them together and I am not sure if they pre drill and tap the heatsinks.
Cutter gives a discount to rollitup members too. Contact Craig (welight user name on here) he will offer any advice.
I do not work for either company, I have spoke to both, hence these are the folks I am mentioning.
Growmau5 has a video on building the cutter kit named after him, its on youtube.

 

[BOBBY_G]

cutter/growmau5 kits dont include aluminum framing so "just a screwdriver" is a little bit of a stretch youd still need to build a frame (which isnt hard)

 

[BOBBY_G]

seems like cree is getting serious on the horti front

http://www.cree.com/News-and-Events/Cree-News/Press-Releases/2016/June/Cree-Expands-Portfolio-of-LEDs-for-Horticulture-Lighting

and i dont remember seeing this before but i may be wrong

http://www.cree.com/xlamp/horticulture

 

[ttystikk]

I'm currently running head to head comparisons of COB LED and HID lighting.

I'm running 5400W, total wattage ballasts included, of 860W CDM Allstart lamps on magnetic ballasts, perhaps not the very latest in HID tech but solid in terms of spectrum response. This lights a rack of 144 sq ft.

I'm also running 5400W of Cree CXB3590 3500K CD BIN 72V chips at 54W each. This also lights a 144sq ft rack.

Early results show that the LED light source is so much more powerful than the HID that the plants were shocked when they went into bloom. They had problems the first three weeks of bloom and some never recovered.

That said, my average yields still went up. I had a new personal best; one plant hit 32oz, up from a previous best of 26oz.

Quality is obviously better; tighter, denser, heavier nugs with more frost. No one disagrees with the assessment that it's also more potent.

COB LED is better. It's better than blurple LED panels as well; in head to head tests, my CXB powered modules drastically outperformed them, growing healthier plants at similar rates with less than half the watts used and heat generated.

From this perspective, all the complaints about COB LED lacking UV light smack of sour grapes; grow a crop under them and then tell me they need more frost, lol

I'd say HID lighting is for streetlights but my city is replacing them with... yep, you guessed it- COB LED! Light bulbs are sooooo twentieth century. If you're still growing under HID, it's time to join the new Millennium.

At this point, it's no longer a question of whether LED is better, it's more a discussion of how the new tech can be most effectively and efficiently deployed.

Just so the purists can't cry foul, I'm also testing a new 1000W class low frequency square wave ballast and I'll be running an 860W CDM Allstart lamp on it. We'll see if the improved performance of this combo will keep it competitive with COB LED.