Think ive been led astray

[Stephenj37826]

What pebbled reflector is one bounce and out umm none lol. That's why Luxor was best reflector period. More of it was mirror one bounce and out. I'm not saying the right reflector can't hit 85% or better but I'm not sure any do right now.

 

[Abiqua]

Yeah I know it's weird how HPS produces more lumens but not higher g/w yelds. I suppose it must be the spectrum or maybe the fact that LEDs run on DC and HPS on AC, which is not steady current. It's rapidly flickering current, though digital ballasts make the flickering a lot faster. Also it's possible that the high infrared of HPS and MH causes some kind of defensive action by the leaves to avoid overheating which then also reduces photosynthesis. Anyway, I'll find out how a stock CXB highbay performs. I only have two plants in there but it's BC Big Bud so should yield pretty well.

Could it be that less efficient wavelengths are being outputted....which give higher lumen counts but lower photon intensity for PAR.....

 

[Stephenj37826]

Could it be that less efficient wavelengths are being outputted....which give higher lumen counts but lower photon intensity for PAR.....

Yeah that's a good point. What do they actually test when they say 95% reflective? Lumens/lux par which par scale. Sure seems to be a pretty big drop in yield vs bare bulb in the right growers hand. It's rare to see over .8 g/w overhead but I've seen a few 1 g/w + vert grows.

 

[GrowLightBoss]

I understand that.
Maybe you can clarify why lumen is the unit of measure used by all cob growers to talk up the efficiency of their lamp if lumens shouldn't be brought into grow light discussions?

Thanks for the hint that this needs to be explained. I'll do my best...

This might help as not all lumens are created equal... The unit we should be measuring light with is PPFD, an acronym for photosynthetic photon flux density.

The ideal PPFD depends on stage and quality of light:

With HPS I tell people 1000 mmol / square meter
With full spectrum I tell people 700-800 mmol / square meter

Why the difference? Well, the HPS dominant green and yellow wavelengths (~500~600nm) of light travel further but are far less useful for photosynthesis. These wavelengths are great for our eyes demonstrated below but not ideal for plants. Each wavelength of light has it's own photosynthesis factor for each type of plant. Plants have optimal photosynthesis <500nm and >600nm, but that being said it's a misnomer that the green wavelengths cannot be used for photosynthesis and do not wake up plants (they do). Thus, you need slightly less mmol of full spectrum lighting to create the same amount of photosynthesis as an HPS.

So what excites me about this industry is there is still so much to learn and so much research left to do around how wavelengths of light effect different strains and how different ratios of wavelengths are consumed.

 

[BobCajun]

Could it be that less efficient wavelengths are being outputted....which give higher lumen counts but lower photon intensity for PAR.....

SK did take PAR readings 18" under the middle of a 1000w HPS and a 400w SK and the version without the parabolic reflector was the same reading, around 1000. The parabolic one was about 15% higher. He didn't actually say it was a 1000w HPS but it looked that size and they did say it was 1000 in other videos using the same grow chambers. I doubt he switched to a 600w for that video. Besides, he also did a lux reading and the HPS was about 93,000. Pretty sure a 600w isn't that bright.

The lux readings were done first in this video and the PAR ones are after that. So in both lux and PAR a 400w Cree LED highbay is slightly higher than a 1000w HPS. Weird but true. Could be because the LEDs shine straight down and HPS shines outward in all directions from the arc tube. If he took reading out from the middle the HPS might be higher.

 

[Abiqua]

SK did take PAR readings 18" under the middle of a 1000w HPS and a 400w SK and the version without the parabolic reflector was the same reading, around 1000. The parabolic one was about 15% higher. He didn't actually say it was a 1000w HPS but it looked that size and they did say it was 1000 in other videos using the same grow chambers. I doubt he switched to a 600w for that video. Besides, he also did a lux reading and the HPS was about 93,000. Pretty sure a 600w isn't that bright.

The lux readings were done first in this video and the PAR ones are after that. So in both lux and PAR a 400w Cree LED highbay is slightly higher than a 1000w HPS. Weird but true. Could be because the LEDs shine straight down and HPS shines outward in all directions from the arc tube. If he took reading out from the middle the HPS might be higher.

Edit: his test showed 31K lumens from Cree....How did they come up with these #'s? Lol....they continue to amaze....

Ehh...I would basically throw out the Lux data without some long drawn out math correlation factoring to compensate for light source.....I get readings of 29K lux from 18" from 122 watts of Cree CXA/Vero 29 3k.....it means nothing other than something is really bright 18" above that spot....

 

[BobCajun]

Edit: his test showed 31K lumens from Cree....How did they come up with these #'s? Lol....they continue to amaze....

Ehh...I would basically throw out the Lux data without some long drawn out math correlation factoring to compensate for light source.....I get readings of 29K lux from 18" from 122 watts of Cree CXA/Vero 29 3k.....it means nothing other than something is really bright 18" above that spot....

The Cree highbays put out about 40,000 lumens, which means that if evenly spread over 1 sq meter it would be 40,000 lux. So obviously it's a lot more concentrated right under it because it read almost 100,000 lux. That's probably only within about a 1 foot diameter circle. Outside that it must be way lower. It would be better if the LED mounting plate was convex so that the LEDs wouldn't all point straight down. I guess nobody thought of that yet.

 

[BobCajun]

I think the red LEDs in the SKs may be a stock configuration for Cree's "TrueWhite" lamps. That's apparently how they made TrueWhite, by adding reds to the whites. That would also explain why there are ambers in the SKs. That's the 590 nm range. Good for eyes but not particularly good for plants.

 

[OLD MOTHER SATIVA]

i have the 90 degree sk and yeh first time flowering with it and i have had it since last winter..never got around to it

it was fairly progressive last winter ..."before cob"

it has good penetration but i have the 90 and they didn't have the 120 when i got it....

i think the 90 could grow a decent single tree

i would put it closer if it was a 120 degree.. quite impressed so far..

we'll see

and again ,thank you to the wonderful knowledgeable and social people here who have made it a lot easier to

understand led/les and get excited about it

 

[BobCajun]

i have the 90 degree sk and yeh first time flowering with it and i have had it since last winter..never got around to it

it was fairly progressive last winter ..."before cob"

it has good penetration but i have the 90 and they didn't have the 120 when i got it....

i think the 90 could grow a decent single tree

i would put it closer if it was a 120 degree.. quite impressed so far..

we'll see

and again ,thank you to the wonderful knowledgeable and social people here who have made it a lot easier to

understand led/les and get excited about it

Just take the reflector off. I have a couple 240w CXB high bays and I was using them with the 60 degree aluminum reflectors that came with them and it wasn't working out well. It was way too strong a beam in the middle. So I took it off and now it's a lot better. I positioned it so that the cobs are almost at the same level as the bottom of the reflector was before and it seemed about right. The light is much better spread out now and it doesn't make your hand feel hot under it like before.

With the 240w CXB high bays, without the reflector the whole thing is about 1 foot diameter and about 2" thick. It's like a disk. Much more convenient to handle than with the 18" reflector on it. You need reflective walls all around the grow space though, of course.

 

[OLD MOTHER SATIVA]

thanks bob,

the two 250 w lights i had made were from 4 x70 w bridgelux i dunno what kind] 4500 k

i had them justput a lens on em..same thing like those 250's..they work very good..but have not flowere dwith em yet

i will remove the reflectorn on the sk

 

[Djloud]

Spectrum King Online Yield reports

#1 John Berfelo : 219.1 grams 0.55gpw

#2 Sir Sly: 255g per light (510g from 2 SK, incl trim) 0.63gpw

#3 SK in house grow: 812g (60deg refl model) 1.8 gpw

#4 Nester Nomad : 448g 1.0 gpw

#5 DrJ 303: 700g 1.22 gpw (weight not proven in video, discussed in YT comments)

If anyone can find other growers proving their yields online, please post, I would love to see some more results.

U will see mine in about a week and ill bet everything on getting over 1.5g per. I know my plants and they are right on par

 

[OLD MOTHER SATIVA]

i am seeing one person on another forum who dialed down his sk.. getting decent looking bud so

it can be done...

i am using mine [again] for veg..its awesome..gonna maybe take the reflector off and try flowering again[maybe not]..

but also look into

if i can upgrade it to cobs..

 

[nevergoodenuf]

The reflector has always been my biggest complaint on the Spectrum King. I bought a stadium light before Spectrum King came out and the first thing I did was change out the reflector for an appropriate hood. Completely changed the foot print to a perfection 4'x4' @ 2'. I am not using it at the moment, but I removed the two HLG-240s and run one HLG-320 now. It may become my veg light soon.

 

[FranJan]

i am seeing one person on another forum who dialed down his sk.. getting decent looking bud so

It's interesting you say that because IMO that lights based on the array design that SK uses have to be run at lower powers to be effective and might warrant a relook. I've tried to use some XPE whites that look like these:

as grow lights and they sucked regardless of how I tried to cool them. But my inner Supra came out one day and I grabbed a 300mA driver and have been using them with great success cloning, keeping small Moms and germming seeds, though clones, Moms and seeds aren't the real game. Actually I'm pretty sure I'm going to dump my Hans panels in my Veg cab for some of these once I free up some cash.

100W CREE XTE XT-E cool white 5500-6000k High power Led 9120lm
http://tinyurl.com/hhr8kg4

Edit: Binning can be a real hassle with these.

 

[Djloud]

The reflector has always been my biggest complaint on the Spectrum King. I bought a stadium light before Spectrum King came out and the first thing I did was change out the reflector for an appropriate hood. Completely changed the foot print to a perfection 4'x4' @ 2'. I am not using it at the moment, but I removed the two HLG-240s and run one HLG-320 now. It may become my veg light soon.View attachment 3626642 View attachment 3626647

I like that reflector. Thats a great idea

 

[nevergoodenuf]

My friends garden store sell new and used equipment. I got it for $25.