Think ive been led astray

GrowLightBoss

GrowLightBoss

Member
Yodaweed said:
Those stasticis are flawed. Genetics play way too big a part in any weight measurements. Here's an example:
You grow Big Bud
I grow a Haze plant
You will yield more than me but my bud will be way higher quality and taste not like shit like big bud does.
Not to mention chemically grown buds yield more but I don't care to smoke cancer so I grow organic and yield less than I used to but smoke way better now.
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Agreed. Simply put, the only way to truly compare is to keep all variables constant (including clones not seeds) in a side by side and have different lights. I've only seen this amount of data logging and attention to detail in university testing. I hope we can all get there eventually.
 
P

PurpleBuz

Well-Known Member
BobCajun said:
Surprisingly enough, the SKs aren't just cool white high bays. They're MOSTLY MK-R 4000k whites but they also have some red and amber XP-E and XP-E2s. Why they added the ambers I don't know, I guess because it's a single spike at 600 nm which is the low red zone. The reds are regular red and photo red. The effect of the added red/amber LEDs appears to be a lowered CCT of 3643, as opposed to the 4000 of the whites. You can view the pdf with all the test data on the products page of their website. So I guess technically they can call it a grow light with a custom spectrum, by adding those reds and ambers. My guess is that simply getting a warm white high bay would have similar results though, since the spectral distribution of the SK is so close to that of warm white LEDs that you couldn't tell them apart if they weren't labeled. Could have saved themselves some trougnle by just using warm white high bays but I gues they wanted to make their lights look somehow special.
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these extra reds imho improve the SK spectrum significantly, wider fatter higher overall CRI. Its the one thing that I like about the SKs. .
 
BobCajun

BobCajun

Well-Known Member
PurpleBuz said:
these extra reds imho improve the SK spectrum significantly, wider fatter higher overall CRI. Its the one thing that I like about the SKs. .
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Yes but would they put out more light if they instead used all war whites? Red LEDs put out about 27 lm/w. I know l
PurpleBuz said:
these extra reds imho improve the SK spectrum significantly, wider fatter higher overall CRI. Its the one thing that I like about the SKs. .
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Adding reds to whites does seem to help. The SKs are about 25% reds. However, nobody has done a direct comparison between an SK and a standard 4000k high bay.
 
BobCajun

BobCajun

Well-Known Member
I don't know about these highbays. I just got a 240w one and it's about half the weight of an SK and it's still too damn heavy to handle conveniently. The problem with LED lamps is the big heatsinks they need. This one has the driver bolted onto the heatsink with weird shaped screw holes that I don't even have a screwdriver for so I can't even take it off to reduce the weight. At least unless I can find such a screwdriver. The light is also concentrated in the middle. When someone invents a lightweight LED highbay they may be convenient to use. Glad I canceled my SK order. That thing would have been monstrous. If anyone wants to use retail LED fixtures then get a bunch of small ones instead of a few big ones. Anything over 100w is gonna be too damn big and heavy.
 
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Stephenj37826

Stephenj37826

Well-Known Member
Or get an led grow light that is active cooled. I have a cxa fixture coming out next week that will kill an SK is cheaper and more efficient. It weighs 19 lbs.
 
BobCajun

BobCajun

Well-Known Member
captainmorgan said:
It's a sealed passive cooled light so of course it's going to be heavy.
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It gets pretty damn hot too. You couldn't hold your hand on top the heatsink for any length of time. Anyway, I did get it in place. I was using a 3' x 1.5'x 5' high portable clothes closet as the chamber. It's made of white non-woven fabric over a metal frame. Since the lamp is so hot and bright what I did was cut a hole in the top the size of the reflector and I have it so the whole lamp is outside the top of the chamber. It's barely hot inside at all, cooler than it was with the 150 HPS bulb I had in there before. Hopefully the increase in wattage won't harm the plants. No infrared like HPS so they probably won't burn. The HPS was a lot closer too.

Here's the unit. Notice how two of them would cost several hundred dollars less than one 400w SK and have 80 watts more output. It sits on a couple pieces of metal I put across the top so just the outer edges of the aluminum reflector are supported. The reflector is almost as wide as the chamber is deep actually. I could almost support it on the tent bars but they were slightly too far apart so I need the pieces of metal.

The actual LEDs are a full 3' above the canopy and it's a very nice looking coverage, nice and even at that height, penetrates right to the bottoms of the plants, which are about 18" high. Seems like just the right wattage for that size chamber actually, should work quite well. But that's the way to do it though if you're using a tent type grow chamber, have the whole lamp outside the top. Looks like this purchase turned out well. If you had a 3'x3' you'd need two of them. In fact I'll get another one now since I'm happy with it.

Had to put some black fabric on the outside of the thing because the light goes right through the fabric, though most is reflected back inside. I didn't want to use a commercial tent because of the expense and also because they are completely impervious to humidity. With the fabric air and humidity can pass through the walls and I don't need ventilation at all, which I didn't want to have to use. Hopefully the fabric won't mold but if it does I'll have to take it off and wash it with bleach between crops. It's not completely closed, the zipper is unzipped. The black fabric is over where the zipper is though so light can't get in but air can get in from below at floor level. So far so good, two weeks in. We'll see how the 240w CXB highbay portable closet grow goes.
 
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OneHitDone

OneHitDone

Well-Known Member
BobCajun said:
It gets pretty damn hot too. You couldn't hold your hand on top the heatsink for any length of time. Anyway, I did get it in place. I was using a 3' x 1.5'x 5' high portable clothes closet as the chamber. It's made of white non-woven fabric over a metal frame. Since the lamp is so hot and bright what I did was cut a hole in the top the size of the reflector and I have it so the whole lamp is outside the top of the chamber. It's barely hot inside at all, cooler than it was with the 150 HPS bulb I had in there before. Hopefully the increase in wattage won't harm the plants. No infrared like HPS so they probably won't burn. The HPS was a lot closer too.

Here's the unit. Notice how two of them would cost several hundred dollars less than one 400w SK and have 80 watts more output. It sits on a couple pieces of metal I put across the top so just the outer edges of the aluminum reflector are supported. The reflector is almost as wide as the chamber is deep actually. I could almost support it on the tent bars but they were slightly too far apart so I need the pieces of metal.

The actual LEDs are a full 3' above the canopy and it's a very nice looking coverage, nice and even at that height, penetrates right to the bottoms of the plants, which are about 18" high. Seems like just the right wattage for that size chamber actually, should work quite well. But that's the way to do it though if you're using a tent type grow chamber, have the whole lamp outside the top. Looks like this purchase turned out well. If you had a 3'x3' you'd need two of them. In fact I'll get another one now since I'm happy with it.

Had to put some black fabric on the outside of the thing because the light goes right through the fabric, though most is reflected back inside. I didn't want to use a commercial tent because of the expense and also because they are completely impervious to humidity. With the fabric air and humidity can pass through the walls and I don't need ventilation at all, which I didn't want to have to use. Hopefully the fabric won't mold but if it does I'll have to take it off and wash it with bleach between crops. It's not completely closed, the zipper is unzipped. The black fabric is over where the zipper is though so light can't get in but air can get in from below at floor level. So far so good, two weeks in. We'll see how the 240w CXB highbay portable closet grow goes.
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Curious how this led produces.
Interesting that a 250W hps puts out over 10,000 lumens more than this led
 
OneHitDone

OneHitDone

Well-Known Member
alesh said:
Lumens are for humans, lumens are for humans, [...]
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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? ;)
 
alesh

alesh

Well-Known Member
OneHitDone said:
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? ;)
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Sure. They're comparing white COBs which have identical or very similar LER.
HIDs have very different LER and red LEDs as well.
 
OneHitDone

OneHitDone

Well-Known Member
alesh said:
Sure. They're comparing white COBs which have identical or very similar LER.
HIDs have very different LER and red LEDs as well.
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So it is possible for a lamp with a lower "lumen per watt" to outperform one of much higher numbers when comparing different types of light sources?
 
BobCajun

BobCajun

Well-Known Member
OneHitDone said:
Curious how this led produces.
Interesting that a 250W hps puts out over 10,000 lumens more than this led
Click to expand...
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.
 
Stephenj37826

Stephenj37826

Well-Known Member
BobCajun said:
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.
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My theory is it's some spectrum but mostly reflector loss. Look up some of the better vert grows. Gpw goes up with bare bulb vert if the environment is correct. Best I ever did was just over 1 gpw bare bulb vert. So if you take that into consideration and then spectrum 1.5 gpw with a more efficient light source isn't that far stretched really.
 
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