Quantum Boards or COBS?

Fishbulb

Fishbulb

Well-Known Member
So cobs or quantum boards?

2.4m tent ? ,8 plants

I used to use hps. Now I run 600watts of citizens on one side what should I use on the other ?

2x 600hps didn't get the weight I wanted but with the cobs and hps I saw a massive jump in yeild now I want to know what to do either the other side. Any help or comments will greatly appreciated
 
nfhiggs

nfhiggs

Well-Known Member
NewBKind said:
An LED works by passing one electron at a time between contacts in an arc, hps/mh/cmh has to HEAT a filament to glow HOT enough to create the light you desire, complemented by various elements such as sodium to produce a specific spectrum. An arc of electricity does not need to ever get hot to create light, it works by allowing electrons to freely escape in the form of photons!
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LOL- Son, you need to go back to whatever school taught you that nonsense and demand a refund. Neither of those descriptions even come close to reality.
 
Olive Drab Green

Olive Drab Green

Well-Known Member
nfhiggs said:
LOL- Son, you need to go back to whatever school taught you that nonsense and demand a refund. Neither of those descriptions even come close to reality.
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HPS uses incandescent High Intensity Discharge technology, which heats up a filament of metal and sodium, wasting wattage on heat, that much is right. LEDs work by electroluminescence in which an arc of electricity over the phosphor chip of an emitter is used for light, producing less heat and more PAR-rich light due to less energy being wasted on heat. Electroluminescence is obviously more efficient, at least where COBs are concerned. I don’t think it’s one electron at a time, though.
 
DesertPlants

DesertPlants

Well-Known Member
There is a lot of misconceptions and misunderstanding about how different lights work on this thread.

Thermodynamics first law... energy can be neither crates or destroyed. 1000w is 1000w. BUT. The third law says the entropy reaches constant value as it approaches zero.

The cooler an object is, the more energy is available for use instead of converted to heat. Theororehtical example: two light bulbs, one running at 1 kelvin, one running 358 kelvin, all other things being the same, the colder one will convert more electricity into photons as less energy is converted to heat.

Same thing we are talking about here... except we are not just comparing photons, we are comparing the spectrum those photons are emitted in. There is no direct 1-to-1 comparison because you are comparing two different things.

As for UV and IR... yes some can be used by plants, but the actual impact of those frequencies is not fully understood. There hasn’t been many fully scientific tests on impact or the ability to say something like 50 photons of white light is more beneficial to a plant than 50 photons of near IR.

At the levels of efficiency we are discussing, more isolated testing needs to be done. You also can’t account for genetic differences strain to strain or between phenotypes.

TL;DR: Use what works for you.
 
nfhiggs

nfhiggs

Well-Known Member
Olive Drab Green said:
HPS uses incandescent High Intensity Discharge technology, which heats up a filament of metal and sodium, wasting wattage on heat, that much is right. LEDs work by electroluminescence in which an arc of electricity over the phosphor chip of an emitter is used for light, producing less heat and more PAR-rich light due to less energy being wasted on heat. Electroluminescence is obviously more efficient, at least where COBs are concerned. I don’t think it’s one electron at a time, though.
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None of it is right except for LEDs being more efficient at creating usable photons per watt. There is no filament in an HPS - it is not "incandescent" in any way whatsoever. It uses an electric arc passed between two electrodes inside a gas filled tube. Have you not ever wondered why they used to be called "sodium arc lights"?

There is no "arc" in a diode. It is simply current passing through a semiconductor PN junction doped with certain materials. As the electrons move to fill the holes in the PN junction barrier region, they emit photons. Those photons pass through and excite the phosphor coating that spreads out the spectrum turning it from 465 nm blue light to white light..
 
wietefras

wietefras

Well-Known Member
DesertPlants said:
The cooler an object is, the more energy is available for use instead of converted to heat. Theororehtical example: two light bulbs, one running at 1 kelvin, one running 358 kelvin, all other things being the same, the colder one will convert more electricity into photons as less energy is converted to heat.
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and those photons are ultimately converted to heat. Apart from the tiny fraction which goes into bio matter for the plant growth, but that is also the same in both cases. So it's still the same for HPS and LED meaning that a 1000W LED or 1000W HPS warm up a closed room at the same pace.

The main difference between heat coming off LED and HPS is that HPS mostly radiates IR, while leds give off more convectional heat. The radiated heat from HPS ends up on the plants making it harder to cool while the convection heat from the leds rises up and goes out the exhaust without ever reaching the plants. So even though the heat production is exactly the same W for W, the led heat is easier to evict from the room. So much so that many people actually have trouble keeping the room warm enough (especially while also keeping the humidity low enough).
 
DesertPlants

DesertPlants

Well-Known Member
wietefras said:
and those photons are ultimately converted to heat. Apart from the tiny fraction which goes into bio matter for the plant growth, but that is also the same in both cases. So it's still the same for HPS and LED meaning that a 1000W LED or 1000W HPS warm up a closed room at the same pace.

The main difference between heat coming off LED and HPS is that HPS mostly radiates IR, while leds give off more convectional heat. The radiated heat from HPS ends up on the plants making it harder to cool while the convection heat from the leds rises up and goes out the exhaust without ever reaching the plants. So even though the heat production is exactly the same W for W, the led heat is easier to evict from the room. So much so that many people actually have trouble keeping the room warm enough (especially while also keeping the humidity low enough).
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No... that’s not true at all. Conversion of energy does not always mean heat. Not all reactions are exothermic. Conversion of 1000w is true, but saying it is all heat is incorrect.

Photons are not heat. They don’t dissipate because it is colder... that’s not how they work.
 
wietefras

wietefras

Well-Known Member
DesertPlants said:
No... that’s not true at all. Conversion of energy does not always mean heat. Not all reactions are exothermic. Conversion of 1000w is true, but saying it is all heat is incorrect.

Photons are not heat. They don’t dissipate because it is colder... that’s not how they work.
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Yes that IS how it works. We are talking about physics here and not chemistry. It's the photons hitting and being absorbed by the walls or being absorbed by the plants warming them up.

It's pointless obfuscating the matter by considering chemical reactions in the plants. As I already indicated these are also equal for both led and HPS anyway.
 
wietefras

wietefras

Well-Known Member
@DesertPlants, Photosynthesis is irrelevant when considering rooms warming up. Only a small fraction of the total radiated energy from the lights is used for photosynthesis and its also the SAME for both HPS and LED light. So the end result is still that both lights heat up the space at the same speed.

Or is it perhaps that you want to argue that with LED it might go 2% slower than with HPS because of extra photosynthesis, because I'd be fine with conceding to that. I'd rather ignore such insignificant potential differences though and call it even.
 
DesertPlants

DesertPlants

Well-Known Member
1000w going through 70% efficient LEDs will lose 30% to heat, that same 1000w through a MH or HPS bulb at 55% efficiency, will convert 45% to heat. The difference is the ratio of energy converted to heat versus usable photons... which in turn are converted to chemical energy (with some obvious loss in conversion). If it was thermal energy, the plant could still use it and I would agree with you, but they are converted to chemical energy.

15% additional heat loss in HPS is what heats the room more and reduces photon output. It all ties together... that’s why I was bringing it up.


We disagree and I’m ok with that. Regardless... it’s nice to see people interested in making things improve constantly.
 
wietefras

wietefras

Well-Known Member
DesertPlants said:
15% additional heat loss in HPS is what heats the room more and reduces photon output.
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See that's what I was afraid of, because that's where you are completely wrong.

Only a few percent of those extra photons are converted to bio mass. The rest ends up as heat. It's really an insignificant difference and the rooms will heat up at the same pace.
https://en.wikipedia.org/wiki/Photosynthetic_efficiency

You would be right if you say that could use only a 700W led light vs a 1000W HPS bulb, but that wasn't the claim made. Watt for watt the heat generation is equal for both.
 
nfhiggs

nfhiggs

Well-Known Member
DesertPlants said:
No... that’s not true at all. Conversion of energy does not always mean heat. Not all reactions are exothermic. Conversion of 1000w is true, but saying it is all heat is incorrect.

Photons are not heat. They don’t dissipate because it is colder... that’s not how they work.
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Explain to us what reactions involving LIGHTS and the grow room are endothermic? Photosynthesis has already been accounted for and removed from the equation....
 
DesertPlants

DesertPlants

Well-Known Member
nfhiggs said:
Explain to us what reactions involving LIGHTS and the grow room are endothermic? Photosynthesis has already been accounted for and removed from the equation....
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It has not been removed... Photosynthesis is the reaction used for plants to turn the usable energy into something more useful to the plant. You cannot cut half a process out and just focus on one side when both of them work in tandem. Photosynthesis is endothermic. The light is not all converted to either plant fiber or heat. You are trying to say heat and photons are the same thing. They are not the same thing at all. They are both forms of energy, yes. They do both equate to the same total energy... but you can't say that one source creating 300W of heat and 700W of photons creates the same heat as one that creates 450W of hear and 550W of photons. The energy is converted to chemical energy, not just heat.

6CO2 + 6H2O -> C6H12O6 + 6O2

Plants have an overall conversion efficiency of 3%-6% the rest is emitted as heat and chlorophyll fluorescence. At 6% efficiency, 700w = 42W converted chemical energy and 550W = 33W converted energy. That is 11.5% more usable energy converted to chemical energy. Yes the numbers are small, but I wasn't arguing that they are huge, I was arguing that the usable energy, based off the efficiency, makes a difference and isn't all heat. Again, the levels emitted from the light source of different wavelengths impact the ratios of heat, chemical energy, and chlorophyll fluorescence. More testing needs to be done on these ratios to determine more accurate spectrum mapping for lights.

As a side note, depending on the environment of the plant, the added heat of an HPS bulb may help as plants are more efficient at converting energy in a specific temperature range. Having too much heat "evaporate" can harm the plants. At the same time, letting the plant emit the energy after absorption and conversion to chemical energy and chlorophyll fluorescence may be beneficial if you're running the room at a higher temperature. The water in the plant acts as an active cooling system and helps severely increase the surface area of the heat being emitted and overall reduces the hotspots that would result in burning had the energy been converted to heat at the light source as opposed to by the plant after the photosynthetic conversion.
 
Roger A. Shrubber

Roger A. Shrubber

Well-Known Member
both lights produce photons. when photons hit something, some of them are reflected, and some of them are absorbed, and turn into heat....the reflected ones are eventually absorbed and turn into....heat....you cannot destroy energy, you can only turn it into some other form of energy, so if a device used 1000k watts, it will eventually produce 1000 watts of waste heat, from its actual operation, and from the environment around it absorbing the energy its radiating...you cannot deny a law of thermodynamics, wiser people than all of us discovered these things, and they've been immutable ever since.
 
DesertPlants

DesertPlants

Well-Known Member
Roger A. Shrubber said:
if a device used 1000k watts, it will eventually produce 1000 watts of waste heat
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No, you can't convert some energy into chemical energy, some into chlorophyll fluorescence, and still get 100% energy out as heat. You can't convert 100% of energy emitted, to 106% (or whatever number you use as an example) energy consumed. You cannot create energy... first law of thermodynamics. If 6% of energy goes to chemical energy, you are left with 94% of energy for heat and chlorophyll fluorescence... not 100%.[/
 
DesertHydro

DesertHydro

Well-Known Member
Yodaweed said:
Only problem is in my opinion no 675w LED will compare yield wise to a 1300w DE gavita. The yield losses would pay for the gavita in one run alone in my opinion.

Here's a great side by side, basically what you just said, (1650watts of top bin citizens vs 2300w of gavita), the gavita yielded 50% more.

https://www.rollitup.org/t/test-room-de-hps-vs-citizen-cobs.935306/

To me results like that show you gonna need nearly even wattage to compete with these DE and CMH lights, and at that point you just lost the only advantage LEDs had since their spectrum isn't that desirable.
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i read that whole thread and he said there was only a 2oz difference between the two tables or am i looking at the wrong thing here?
 
DesertHydro

DesertHydro

Well-Known Member
Fishbulb said:
So cobs or quantum boards?

2.4m tent ? ,8 plants

I used to use hps. Now I run 600watts of citizens on one side what should I use on the other ?

2x 600hps didn't get the weight I wanted but with the cobs and hps I saw a massive jump in yeild now I want to know what to do either the other side. Any help or comments will greatly appreciated
Click to expand...
i still use mostly HPS but im slowly moving over to LED. with COBs im doing about 650w to cover a 4x4 extremely well. i have yet to try out quantum boards but think i will be building a couple rigs very soon. the plan is to use 4 boards to cover a 4x4 with a single 600w driver. big heatsinks and lots of airflow. greengrassgrower1 is killing it with this setup and i would be happy emulate his results.

i think you will be fine either route you go. i wanna try out QBs just because they are new and more efficient than what i have right now but my guess is the results will be very similar in the end. i do like the simplicity of their builds though. 4 boards to wire rather than 16 cobs
 
Rocket Soul

Rocket Soul

Well-Known Member
DesertPlants said:
It has not been removed... Photosynthesis is the reaction used for plants to turn the usable energy into something more useful to the plant. You cannot cut half a process out and just focus on one side when both of them work in tandem. Photosynthesis is endothermic. The light is not all converted to either plant fiber or heat. You are trying to say heat and photons are the same thing. They are not the same thing at all. They are both forms of energy, yes. They do both equate to the same total energy... but you can't say that one source creating 300W of heat and 700W of photons creates the same heat as one that creates 450W of hear and 550W of photons. The energy is converted to chemical energy, not just heat.

6CO2 + 6H2O -> C6H12O6 + 6O2

Plants have an overall conversion efficiency of 3%-6% the rest is emitted as heat and chlorophyll fluorescence. At 6% efficiency, 700w = 42W converted chemical energy and 550W = 33W converted energy. That is 11.5% more usable energy converted to chemical energy. Yes the numbers are small, but I wasn't arguing that they are huge, I was arguing that the usable energy, based off the efficiency, makes a difference and isn't all heat. Again, the levels emitted from the light source of different wavelengths impact the ratios of heat, chemical energy, and chlorophyll fluorescence. More testing needs to be done on these ratios to determine more accurate spectrum mapping for lights.

As a side note, depending on the environment of the plant, the added heat of an HPS bulb may help as plants are more efficient at converting energy in a specific temperature range. Having too much heat "evaporate" can harm the plants. At the same time, letting the plant emit the energy after absorption and conversion to chemical energy and chlorophyll fluorescence may be beneficial if you're running the room at a higher temperature. The water in the plant acts as an active cooling system and helps severely increase the surface area of the heat being emitted and overall reduces the hotspots that would result in burning had the energy been converted to heat at the light source as opposed to by the plant after the photosynthetic conversion.
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This whole nitpicking details is a bit silly. Surely, when your doing these calculations on photosynthetic efficiency rates, you realize that the rate is based on the light that hits the leaf, not the total light?
Im not saying youre wrong, obviously some of the light gets converted by photosynthesis, and yeah, i used to make this argument myself, but to go thru all these calculations in order to prove your right, it just seems a bit silly especially when the reasoning behind the numbers is a bit lacking.
 
DesertPlants

DesertPlants

Well-Known Member
Rocket Soul said:
This whole nitpicking details is a bit silly. Surely, when your doing these calculations on photosynthetic efficiency rates, you realize that the rate is based on the light that hits the leaf, not the total light?
Im not saying youre wrong, obviously some of the light gets converted by photosynthesis, and yeah, i used to make this argument myself, but to go thru all these calculations in order to prove your right, it just seems a bit silly especially when the reasoning behind the numbers is a bit lacking.
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I was using example numbers, not exact numbers. I was demonstrating a concept, not a specific use-case. I'm not nitpicking the details. I was saying, in my opinion, LED lights appear to convert more usable energy at the higher efficiency than HPS and that not all energy goes to heat. That's all.
 
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