Have any of you DIY COB Growers finished a crop under 1000W DE HPS? - POLL

[Sativied]

So, you are pretengineering (while parroting Supra's posts) that lumens alone doesn't make a good comparisson, because efficiancy matters? Did you really need to quote me for that, so blatantly out of context again, bolding part of a quote I quoted... I never suggested a comparison on lumens alone was the way to go, one of your led buddies here recommend that light that made the comparison.

It's stupid to compare the lumen output between HPS and Cree led cobs since HPS has a higher LER and would have a much higher lumen output if both lighting devices were 100% efficient.

Yeah it sure is stupid to compare just the lumen output between HPS and Cree IF you only care about efficiency and efficiancy. "If both lighting devices were 100% efficient"... another very big hypothetical IF.

The lumen output listed by phillips for the DE is according to Phillips, as I posted in the past, the output in the PAR region. We already established there are reflector losses. And the ballast reducing efficiency by using more wattage is another factor that influences efficiency ratings. The output however is not a result of efficiency numbers (ledlogic), the input and output determine the efficiency numbers (reality), which is irrelevant when comparing merely the output.

You basically create your own specific context in which it would be stupid to compare lumens, while in many more realistic and practical situations comparing lumens can still be useful and make other comparisons unnecessary. For example when led companies make skewed lumen comparissons... It will on its own obviously not be useful to make a comparisson in terms of efficiency, regardless of how you quantify or calculate it as that obviously requires more than one input parameter.

 

[Sativied]

May have been posted before at riu, quick search in google didn't show it has, so dropping this in this thread:

Analysis of Environmental Effects on Leaf Temperature under Sunlight, HPS, LED
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0138930

Reminds me of a few funny discussions... (led vs double ended 2014)

Looks like NIR is highly inefficient (on the plant side, not talking led efficiency per se).

"HPS more effectively transfers heat to the canopy".

While not cannabis-specific research it does mention cannabis flowers in the context of temp of fruits rather than leaves, which are rather effective at absorbing light of various wavelengths simply for having additional layers to absorb it. They present that as a possibility to lower the temp inside those fruits/flowers, while I can imagine I'd like to do the opposite during colder seasons, i can imagine it to be an advantage when you really want to push ppf in hotter climates.

When all other factors are equal, the difference in leaf temp between led and hps is only 1.3C under "typical grow conditions". In different conditions it can be a 3C difference.

Above all, based on the statistics in the doc one can gauge the leaf temp under various types of lighting. For example, with led at 850umol and 25C air temp (and the remaining listed default parameters), the leaf temp is the air temp. At 1400ppf it's air temp+2C. At 1500ppf hps at 25c air temp the leaf temp is air temp+ 5C. 1000ppf hps is air temp +2c.

Unfortunately, it does not include a mh test. Would have been interesting to see the effect of more blue...

 

[frica]

HPS has a higher canopy temp because it also emits quite a bit of IR.
If you want increased canopy temp with led you should add IR leds.

MH also has an IR peak

 

[Sativied]

HPS has a higher canopy temp because it also emits quite a bit of IR.

MH also has an IR peak

Yes, obviously.

If you want increased canopy temp with led you should add IR leds.

Well, that's the thing, I suggested IR leds to add to cobs for warmth before, specifically to be able to control the ppf and plant temp separately. Assume a situation where the temp is not optimal for the ppf (which is clearly the case in some led grows, and more importantly, would be the case for me most if the year). I don't want to run 1500ppf, even if I could get that uniformly, but if I run 1000ppf, with led that is, the leaf temp will be barely 1C higher than the air temp. In practice that could easily translate to a significant loss in net photosynthesis rate (not being able to run 28-30C, but 25 or lower instead) compared to hps.

The IR is a given with hps, part of the inefficient portion basically. Adding IR with led however, would require additional power, thus reduces those theoretic efficiency numbers, reducing the value of the main argument to use led in the first place.

If you had read the doc you also would have noticed that NIR is only absorbed for 20%. It's theoretically very inefficient compared to par light absorption level. On the other hand, the low absorption level increases penetration so it may work out just fine, especially with reflective walls.

Long story short, if the temp doesn't match the ppf, given a led light and hps at the same ppf, the hps can in practice result in more photosynthesis (easily depending on temps) more photosynthesis.

Let me put it differently, according to the data from the doc I posted above combined with the ppf/temp/co2 research from S. Chandra, the IR from HPS effectively increases photosynthesis rate and cannot be discarded as being useless or inefficient. Your led power use efficiency numbers do not translate directly to photosynthesis rate. Unless you have additional means of heating or are in a hot climate, led simply does not produce enough heat for optimal photosynthesis rates.

At 1500ppf and air temp 25c leaf temp is 27C under led and 30C under hps. While the results may vary a lot per variety, especially sat vs indica dom, the added heat can result, according to test results and charts from Chandra in roughly 10-20% more net photosynthesis. Practically evening out the reflector losses associated with hps.

How do you like them apples...

 

[cdgmoney250]

Yes, obviously.


Well, that's the thing, I suggested IR leds to add to cobs for warmth before, specifically to be able to control the ppf and plant temp separately. Assume a situation where the temp is not optimal for the ppf (which is clearly the case in some led grows, and more importantly, would be the case for me most if the year). I don't want to run 1500ppf, even if I could get that uniformly, but if I run 1000ppf, with led that is, the leaf temp will be barely 1C higher than the air temp. In practice that could easily translate to a significant loss in net photosynthesis rate (not being able to run 28-30C, but 25 or lower instead) compared to hps.

The IR is a given with hps, part of the inefficient portion basically. Adding IR with led however, would require additional power, thus reduces those theoretic efficiency numbers, reducing the value of the main argument to use led in the first place.

If you had read the doc you also would have noticed that NIR is only absorbed for 20%. It's theoretically very inefficient compared to par light absorption level. On the other hand, the low absorption level increases penetration so it may work out just fine, especially with reflective walls.

Long story short, if the temp doesn't match the ppf, given a led light and hps at the same ppf, the hps can in practice result in more photosynthesis (easily depending on temps) more photosynthesis.

Let me put it differently, according to the data from the doc I posted above combined with the ppf/temp/co2 research from S. Chandra, the IR from HPS effectively increases photosynthesis rate and cannot be discarded as being useless or inefficient. Your led power use efficiency numbers do not translate directly to photosynthesis rate. Unless you have additional means of heating or are in a hot climate, led simply does not produce enough heat for optimal photosynthesis rates.

At 1500ppf and air temp 25c leaf temp is 27C under led and 30C under hps. While the results may vary a lot per variety, especially sat vs indica dom, the added heat can result, according to test results and charts from Chandra in roughly 10-20% more net photosynthesis. Practically evening out the reflector losses associated with hps.

How do you like them apples...

So in your theoretical situation, why can't the ambient temp of the LED grow room be adjusted to match leaf tempuratures of the plants under HPS? As well as humidity?

Is climate control not allowed in your comparison?

 

[Sativied]

So in your theoretical situation, why can't the ambient temp of the LED grow room be adjusted to match leaf tempuratures of the plants under HPS? As well as humidity?

Is climate control not allowed in your comparison?

Figured them apples would taste very sour for some.

If you want to be a smartass at least make sure it's not dumb what you're posting. Read again, try to comprehend it this time.

See the part that starts with "unless you have additional means of heating or are in a hot climate....". It's not my specific theoretical situation... it's some reality added to theoretical led vs hps comparissons based merely on Bibled efficiency numbers.

That last question... It's not a matter of "allowed" but whether it's relevant. Yet it shows you got a few functioning braincells that do get the point: Led typically needs additional climate control to result in the same photosynthesis efficiency as hps.

It's really not that complicated, we're comparing light setups, not led light+climate control vs hps light. When you compare max speed of two cars do you also add nitro boost to one and not the other? Right, you don't, as that would be silly...

 

[captainmorgan]

So crank up the temps and co2 and grow some nice hay.

 

[testiclees]

Figured them apples would taste very sour for some.

If you want to be a smartass at least make sure it's not dumb what you're posting. Read again, try to comprehend it this time.

See the part that starts with "unless you have additional means of heating or are in a hot climate....". It's not my specific theoretical situation... it's some reality added to theoretical led vs hps comparissons based merely on Bibled efficiency numbers.

That last question... It's not a matter of "allowed" but whether it's relevant. Yet it shows you got a few functioning braincells that do get the point: Led typically needs additional climate control to result in the same photosynthesis efficiency as hps.

It's really not that complicated, we're comparing light setups, not led light+climate control vs hps light. When you compare max speed of two cars do you also add nitro boost to one and not the other? Right, you don't, as that would be silly...

YOUR ANALOGIES ARE AS SHITTY as your condescending tone. Arrogant shit talking clown.

 

[Sativied]

So crank up the temps and co2 and grow some nice hay.

That sour huh...

If you're saying that high end of temp would make terpenes more volatile... you're reaching as that owould be because of the temp then and apply regardless of the light source. With the difference that the ambient temp can be lower with hps to still reach whatever leaf temp you prefer for whatever irrelevant reason besides the obvious, without having to spend additional watts effectively reducing the efficiency of the leds (at the plant, not the led...).

Although less, it applies at other temps too and simply cannot be discarded when comparing photosynthesis efficiency of led vs hps.

Instead of focussing on photon output at the source or a luminated plane, one should obviously be concerned about how efficient the used watts are used for photosynthesis. In case of hps that portion discarded as inefficient in the Bibled because it doesn't fall in the PAR range partly does increase photosynthesis rate.

 

[cdgmoney250]

I have access to a PAR meter and IR temp meter. I have compared relative ppf and leaf temps, and the difference is negligible between 3500K COB and HPS (leaf temps). 2-3 deg. F

Don't blame a light for not being able to manage canopy temps.

Most growers battle the heat of HPS lights.

In case of hps that portion discarded as inefficient in the Bibled because it doesn't fall in the PAR range partly does increase photosynthesis rate.

Can you quantify or extrapolate just how much more that large inefficient portion of spectra (IR) will increase overall photosynthesis?

I'd be willing to bet photons within the VIS range are more productive than photons outside of the VIS range.

 

[a mongo frog]

YOUR ANALOGIES ARE AS SHITTY as your condescending tone. Arrogant shit talking clown.

You seriously don't believe on the issues he reports on?

 

[Sativied]

YOUR ANALOGIES ARE AS SHITTY as your condescending tone. Arrogant shit talking clown.

Meltdown-ballshrinking-sour even... It was one very simple anology and could have been anything where two objects are compared and then a third object is added to skew the comparisson. If you don't have any arguments to add about led vs hps, shut your face fail-troll.

Don't blame a light for not being able to manage canopy temps.

Just more dumb shit attempts to straw man. Nothing what I posted could logically lead to such a conclusion. One uses a light for photosynthesis. The IR from hps increases photosynthesis rate under typical circumstances.

Most growers battle the heat of HPS lights.

No. But if that's the case for you, let me give you some advice potato: "Don't blame a light for not being able to manage canopy temps."

 

[captainmorgan]

I just don't get you,year after year you come trolling the LED section insulting and belittling anyone that disagrees with your religion. How many hours have you wasted trying to convert the unwashed masses. My only thought is that you enjoy conflict and you really don't care what LED people think,it's all just a game to you. There,I've said my piece and I should be good for another year before talking to you again.

 

[AquariusPanta]

@Sativied

Lol, you don't give up very easily do you? Kudos to you, even if we support different lighting methods.

 

[AquariusPanta]

@captainmorgan

LMAO! Right?! It's been at least a year and he's still as persistent as he was before. I jumped into this thread and it was like going back in time for a second, whoa.

 

[cdgmoney250]

Just more dumb shit attempts to straw man. Nothing what I posted could logically lead to such a conclusion. One uses a light for photosynthesis. The IR from hps increases photosynthesis rate under typical circumstances.

Can you quantify or extrapolate just how much more that large inefficient portion of spectra (IR) will increase overall photosynthesis?

Trying to make the shortcomings of a light sound like a benefit.. is reaching, brotato.

 

[churchhaze]

Trying to make the shortcomings of a light sound like a benefit.. is reaching, brotato.

This is exactly what's going on. High efficiency white leds use less power and thus produce less heat, and thus are more versatile. Somehow being more versatile is a disadvantage now.

Bottom line is that in the summer, you use significantly less power, and in the winter, you don't get as much waste heat so you have to use your heater more. This is actually a net gain. Lucky for me, my house came with a furnace. Also lucky for me, natural gas heat costs less than electric heat, so it comes out even more as a win, even in a place with cold winters.

Versatility is not a con, it's a pro.

Also, output is a function of efficiency. If you have higher efficiency with the same input power, you will get a higher output. There's some "ledlogic" for you.

 

[testiclees]

You seriously don't believe on the issues he reports on?

I dig it when issues are raised and substantive points are evaluated and debated. More common though is the absolutist stoner who is more committed to their own practices than learning from others even when presented with conclusive and objective data. This type of stoner often holds that being able to grow weed somehow grants the qualities of wisdom, wit, manliness, self worth, keen intellect etc. The evidence is all around RIU. The result is a juvenile, insecure ego, an arrogant and compulsive know it all.

 

[bicit]

Yes, obviously.

Let me put it differently, according to the data from the doc I posted above combined with the ppf/temp/co2 research from S. Chandra, the IR from HPS effectively increases photosynthesis rate and cannot be discarded as being useless or inefficient. Your led power use efficiency numbers do not translate directly to photosynthesis rate. Unless you have additional means of heating or are in a hot climate, led simply does not produce enough heat for optimal photosynthesis rates.
.

I'd like to see the research from S. Chandra you're referencing specifically. Your first source isn't doing you any favors so I'd like to see what conclusions you're drawing from the other paper. Sounds interesting.

I have more thoughts, but you'll just disregard them so I won't post them.

 

[a mongo frog]

I dig it when issues are raised and substantive points are evaluated and debated. More common though is the absolutist stoner who is more committed to their own practices than learning from others even when presented with conclusive and objective data. This type of stoner often holds that being able to grow weed somehow grants the qualities of wisdom, wit, manliness, self worth, keen intellect etc. The evidence is all around RIU. The result is a juvenile, insecure ego, an arrogant and compulsive know it all.

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I understand what your saying. Its the exact same thing on the other side of the argument though. Whenever people talk better this or better that this type of talk always happens. Theres going to be people wondering about the effectiveness of the cob units until it becomes main stream. I think its on its way there, but its not all over RIU. Plenty to be excited about though. If one of these companies can get into a hydro store and display, more people would start to take notice.