What would you recommend to replace a 1000w HPS in a 4x4 tent?

Yodaweed

Well-Known Member
Thanks for all of the recommendations guys. So I'm basically down to two choices, the 900w Cree CXB3590 kit with 12 COBS at 385 PAR watts, or the 900w Vero29 V7 kit with 9 COBS at 450 PAR watts. Which of these two would you guys think is better for a 4x4 flower only tent? I know the Vero kit is much more efficient and has significantly higher PAR watts, it's also $300 cheaper than the 900w Cree kit, but only has 9 COBS, so I'm assuming that the Cree kit has better coverage up close than the Vero? I see everywhere on the site everyone praising the CXB3590's but are the Vero's also really good? I wanna get the best of the two and not have to buy another light for many years until this one fails in some way, but if the differences are minimal, I'd also like to save $300 lol. Thanks in advance for any help guys.
if you go from 1000w to 900w there's not gonna be a huge difference in heat(only 100w(which is about 340 BTU}[all light sources produce the same amount of heat only thing that matters is the watts that's being used]), i'd go with as least watts possible to get the job done, maybe a 700w or 650w setup.
 

nevergoodenuf

Well-Known Member
I totally believe the science behind that, but If you only had a wall fan moving air in a 5'x5' tent with NO intake/exhaust on a comfortable 72* day, how hot will your 1000w HPS get the tent?
My 1000watt led after a couple hours....IMG_20170313_135939354.jpg
COB'S of course.
 

Dr.Pepper99

Active Member
if you go from 1000w to 900w there's not gonna be a huge difference in heat(only 100w(which is about 340 BTU}[all light sources produce the same amount of heat only thing that matters is the watts that's being used]), i'd go with as least watts possible to get the job done, maybe a 700w or 650w setup.
Ya I hear you watt for watt heatwise. Heat is only a big problem in the hottest 2 or 3 months of summer here though (northern Quebec). I'm thinking I could just dim the 900w down down to 2/3 power, making it approximately 600w during those months. I'm also gonna run my 12/12 cycle from 7pm-7am on, whereas right now I'm doing it from 7am-7pm, that should help a lot with the heat. In the winter like right now I can run everything full blast and with my window open just a crack and have the temps wherever I want them, it gets to -40C (-40F) here some days, but in the summer never any higher than 30-35C (86-95F). I'm thinking I'm going to go with the 900w Cree, deciding between 3000k and 3500k now though, decisions decisions lol
 

Dr.Pepper99

Active Member
I totally believe the science behind that, but If you only had a wall fan moving air in a 5'x5' tent with NO intake/exhaust on a comfortable 72* day, how hot will your 1000w HPS get the tent?
My 1000watt led after a couple hours....View attachment 3906228
COB'S of course.
I have an intake fan at the bottom of my tent attached to ducting placed just under my windowsill for cold air intake and an air cooled xxl hood hooked up to 6" inline fan with ducting long enough to go outside of the bedroom to expel the hot air. Last summer my air management wasn't quite setup as good and I had temps very similar to yours, 85-95+, I had to run my hps at 50-75% most of the time. I've been running DWC all winter, but I think I'm gonna try 5g coco smart pots for the 1st time after my next run in June because I don't wanna risk root rot with the high temps. I was doing frozen water bottles to keep my res temps down for my first run last fall, and what a major pain in the ass that was lol...
 

MeGaKiLlErMaN

Well-Known Member
Thanks for all of the recommendations guys. So I'm basically down to two choices, the 900w Cree CXB3590 kit with 12 COBS at 385 PAR watts, or the 900w Vero29 V7 kit with 9 COBS at 450 PAR watts. Which of these two would you guys think is better for a 4x4 flower only tent? I know the Vero kit is much more efficient and has significantly higher PAR watts, it's also $300 cheaper than the 900w Cree kit, but only has 9 COBS, so I'm assuming that the Cree kit has better coverage up close than the Vero? I see everywhere on the site everyone praising the CXB3590's but are the Vero's also really good? I wanna get the best of the two and not have to buy another light for many years until this one fails in some way, but if the differences are minimal, I'd also like to save $300 lol. Thanks in advance for any help guys.
I would go with the vero if you refuse to make the light.
 

MeGaKiLlErMaN

Well-Known Member
if you go from 1000w to 900w there's not gonna be a huge difference in heat(only 100w(which is about 340 BTU}[all light sources produce the same amount of heat only thing that matters is the watts that's being used]), i'd go with as least watts possible to get the job done, maybe a 700w or 650w setup.
True but that's over a sertain amount of time, the light will eventually become heat but since there's 15% less IR that is a heat savings As HPS produces that percent, cobs don't.
 
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sixstring2112

Well-Known Member
Thanks for all of the recommendations guys. So I'm basically down to two choices, the 900w Cree CXB3590 kit with 12 COBS at 385 PAR watts, or the 900w Vero29 V7 kit with 9 COBS at 450 PAR watts. Which of these two would you guys think is better for a 4x4 flower only tent? I know the Vero kit is much more efficient and has significantly higher PAR watts, it's also $300 cheaper than the 900w Cree kit, but only has 9 COBS, so I'm assuming that the Cree kit has better coverage up close than the Vero? I see everywhere on the site everyone praising the CXB3590's but are the Vero's also really good? I wanna get the best of the two and not have to buy another light for many years until this one fails in some way, but if the differences are minimal, I'd also like to save $300 lol. Thanks in advance for any help guys.
the vero kit is a no brainer if you like saving money and having more light haha. some of us here speak highly of cree because there are alot more grows using them here to reference.everyone else came out with new model chips that meet or beat cree (suposedly) and cree has not come down enough in price to be competitive in the cob market.i still use cree in all my builds but i have some vero cobs also and they grow awesome plants.
 

CobKits

Well-Known Member
Thanks for all of the recommendations guys. So I'm basically down to two choices, the 900w Cree CXB3590 kit with 12 COBS at 385 PAR watts, or the 900w Vero29 V7 kit with 9 COBS at 450 PAR watts. Which of these two would you guys think is better for a 4x4 flower only tent? I know the Vero kit is much more efficient and has significantly higher PAR watts, it's also $300 cheaper than the 900w Cree kit, but only has 9 COBS, so I'm assuming that the Cree kit has better coverage up close than the Vero? I see everywhere on the site everyone praising the CXB3590's but are the Vero's also really good? I wanna get the best of the two and not have to buy another light for many years until this one fails in some way, but if the differences are minimal, I'd also like to save $300 lol. Thanks in advance for any help guys.
vero all day long for all the reasons you listed.

esp in a square i see no reason that 12 cobs are significantly different on coverage vs 9.

at 18" distance to canopy 9 cobs will do great in a 4x4. 900W is a helluva lot for that space you'll prob be dimming down to 75-80W/cob .
 

Yodaweed

Well-Known Member
A 1000w hps will make more heat then 1000w cod led. Yes 1000w is a 1000w. Hps super heats a gas to make light creating more heat. LEDs do not.
the only thing that matters is how many joules of energy (watts are a measurement of joules over time) was used, 1000w is 1000w (which both are 1000 joules / second) , the energy output is the same , energy cannot be created nor destroyed.

I like the idea of being able to dim that light down, sounds like you'd be able to perfectly dial in the amount of light needed which will help with the heat issues (less watts = less heat).
 

JSheeze

Well-Known Member
the only thing that matters is how many joules of energy (watts are a measurement of joules over time) was used, 1000w is 1000w (which both are 1000 joules / second) , the energy output is the same , energy cannot be created nor destroyed.

I like the idea of being able to dim that light down, sounds like you'd be able to perfectly dial in the amount of light needed which will help with the heat issues (less watts = less heat).
...
Thermodynamics 101:
Energy cannot be created nor destroyed, just transformed.

What E=MC^2 is all about, transforming mass into energy or vice a versa.

Ex:
You can use 1000w to heat an iron or you can use 1000w to power a speaker. The energy used (1000w) is the same. The device your powering transforms the electrical energy from the wall into kinetic energy for the speaker (small vibrations to create sound waves), or thermal energy for the iron.

Not all energy will be transfered into thermal energy (heat) although because of friction there will always be a lil thermal inefficiency in anything, but in the case of an LED vs HPS its quite probable and scientifically sound to assume they have different thermal and operational ineffeciencies. Look at PPFD/W or lumen/w, different ratios have different effeciencies of operation, where does that excess ineffeciency go when comparing? Heat.

first-law-thermodynamics.jpg
 

apollo4201982

Well-Known Member
Hi guys, I've been a member for almost 8 years and I don't think I've ever posted before lol, just lurking and reading lol.

So, my question is; what would you recommend to replace a 1000w HPS in a 4x4 tent? That's what I currently have with an air cooled hood hooked up to a 6" inline fan, but the temperatures in the summer are unmanageable and I want to switch to COB lighting to remedy this. I have a separate area for vegging and do perpetual grows, so the COBS would be for flowering only. I'd like to have the maximum amount of light possible at a 12-18" distance from the canopy without bleaching them and the best possible coverage as well. I'm thinking of going with 3-4 3500k 300 Watt Cree CXB3590 (4) COB Grow Light Kits from Timber Grow Lights. I'm gonna make a 4x4 frame for them from aluminum and have all of the drivers outside of the tent to further reduce any heat. I don't care about the efficiency or power savings as I'm not paying the power where I live, but I can't install an AC because the landlord doesn't allow AC units in his building. So what do you pro LED guys recommend? I know 12 COBS would be good from what I've seen on here, but would 16 be overkill, and possibly also have too much heat in the tent? Thanks in advance guys.
Did you think about a chiller hooked up to your air cooled system? Simething like this
https://www.google.com/aclk?sa=L&ai=DChcSEwjQnoihubneAhUKtcAKHbkeAcgYABAEGgJpbQ&ae=1&sig=AOD64_36zkIr8CTDn2GK2y8IYzI-AbL6vw&ctype=5&q=&ved=0ahUKEwjZlIGhubneAhWpzIMKHfl7DmQQwg8ILw&adurl=https://www.amazon.com/Hydro-Innovations-Ice-Box-6/dp/B002JLAC3I/ref=asc_df_B002JLAC3I/?tag=hyprod-20&linkCode=df0&hvadid=198102932635&hvpos=1o2&hvnetw=g&hvrand=15778522068444647355&hvpone=&hvptwo=&hvqmt=&hvdev=m&hvdvcmdl=&hvlocint=&hvlocphy=9017613&hvtargid=pla-320333056993&psc=1
 

Yodaweed

Well-Known Member
...
Thermodynamics 101:
Energy cannot be created nor destroyed, just transformed.

What E=MC^2 is all about, transforming mass into energy or vice a versa.

Ex:
You can use 1000w to heat an iron or you can use 1000w to power a speaker. The energy used (1000w) is the same. The device your powering transforms the electrical energy from the wall into kinetic energy for the speaker (small vibrations to create sound waves), or thermal energy for the iron.

Not all energy will be transfered into thermal energy (heat) although because of friction there will always be a lil thermal inefficiency in anything, but in the case of an LED vs HPS its quite probable and scientifically sound to assume they have different thermal and operational ineffeciencies. Look at PPFD/W or lumen/w, different ratios have different effeciencies of operation, where does that excess ineffeciency go when comparing? Heat.

View attachment 4226831
Exactly, energy cannot be destroyed, so all energy eventually turns in heat.....and the amount of absorption is extremely inefficient (1-3% of light)so it can safely be ignored....1000w hps = 1000w led.

If you think a light that's 10% effiecent makes 90% heat you are completely ass backwards, 100% of all light turns to heat.

E=mc^2 is not about that's it's about the increased relative mass of a body times the speed of light squared....it has nothing at all to do with grow lights....i really advise you going and picking up a good book on physics you really do not know what you are talking about.

If you still have difficulty grasping this concept i'd advise reading this thread

https://www.rollitup.org/t/heat-from-1200w-of-1212s-vero-29s-cxm-22-cxb3590-compared-to-2x-600w.936071/

Here's some good quotes from other members

Because the light will also turn into heat eventually, and since that light stays in your room it becomes heat in your room.

Photosynthesis stores some energy inside the plant (doesn't become heat), but photosynthesis is rather inefficienct so you can safely ignore it.
So 1200W will always be 1200W.
in a room 1200W of anything is 1200W

will produce the same amount of heat

cobs will give you more usable light for that same 1200W, or an equal amount of light for a lesser wattage, like 800W
 

JSheeze

Well-Known Member
Exactly, energy cannot be destroyed, so all energy eventually turns in heat.....and the amount of absorption is extremely inefficient (1-3% of light)so it can safely be ignored....1000w hps = 1000w led.

If you think a light that's 10% effiecent makes 90% heat you are completely ass backwards, 100% of all light turns to heat.

E=mc^2 is not about that's it's about the increased relative mass of a body times the speed of light squared....it has nothing at all to do with grow lights....i really advise you going and picking up a good book on physics you really do not know what you are talking about.

If you still have difficulty grasping this concept i'd advise reading this thread

https://www.rollitup.org/t/heat-from-1200w-of-1212s-vero-29s-cxm-22-cxb3590-compared-to-2x-600w.936071/

Here's some good quotes from other members
All energy does NOT turn into heat.

If a light is 10% efficienct then that means that it only converts 10% of the energy that it uses into light. Whether the remaining 90% is expelled as heat depends on the way the light works, is it moving perhaps? Is some energy being used up to move it? Otherwise yes, if there's nothing extra to the light a 10% efficiency is going to mean that 90% of the energy consumed is not converted into light and will typically be observed as heat.


E=mc^2
is literally..
(Energy) equals (mass) times (the speed of light constant ~300 million) squared.

That's why atomic bombs are so violent though they are relatively small in mass, comparatively. This is because some mass of the core during the reaction is converted into light, heat, ect, and at an incredible rate (~300,000,000^2).

NOT all energy turns to heat. A speaker that moves from an amount of kinetic energy will not have that same amount of energy go into making heat because it's already been used to move the object (speaker). There may be resulting friction from that movement but the energy used to move the speaker can't be used twice, one time to move the speaker, and then also again to heat the speaker. You can't create energy out of nowhere.


I think we're on the same page although your a little bit off on your reasoning and explanation. The point of using LED over HPS is because they are more efficient and have less thermal runoff (more efficient, more ppfd/w, more lm/w, less heat/w), thus why you'd use LED if you were trying to cut heat while keeping PPFD unchanged.


I studied thermodynamics in college as per the general required curriculum for Engineering majors. If you don't understand the laws of thermodynamics that's ok, and I really shouldn't have replied, but I did out of a little engineering pride, and to that end I'm not trying to be confrontational I just know this stuff on a professional level.

LEDs and HPS produce light via different methods. Thus the difference in efficiency, which directly correlates to thermal runoff. The higher the efficiency the cooler the tech.



https://en.m.wikipedia.org/wiki/Mass–energy_equivalence


**scroll down to the "Efficiency" sub heading...
 
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wietefras

Well-Known Member
All energy does NOT turn into heat.

If a light is 10% efficienct then that means that it only converts 10% of the energy that it uses into light.
And most of this light eventually gets converted into heat. Only a few percent gets converted to biomass, but the rest all results in heating up the plants, walls, floor etc after it's absorbed.
 

JSheeze

Well-Known Member
And most of this light eventually gets converted into heat. Only a few percent gets converted to biomass, but the rest all results in heating up the plants, walls, floor etc after it's absorbed.
Light and infrared radiation are electromagnetic waves but they operate at different wavelengths/frequencies and effect matter differently at the atomic level.

If your light emits a wide EM band like HPS some of your energy is realized as infrared or non utilized wavelengths and thus the less efficient mechanism for producing visible light because your wasting some energy emitting wavelengths that aren't seen or utilized only transformed into heat.

LEDs emit a narrow EM band and so less energy is used for non utilized wavelengths (if you purchase the correct color temp), including infrared. This helps increase the efficiency of the mechanism when concerning the production of visible light.

When talking about a tent or the temperature of a system I'm not convinced that the majority of heat observed is from visible light interacting with water filled plant matter. In fact I'm almost certain it accounts minimally in overall temp realization compared to that of the heat of the emitting source (filament, LED) or power supply electronics.

The question is, how much of visible or utilized light is converted into heat, and I don't know enough to say.
all energy eventually turns in heat.....and the amount of absorption is extremely inefficient (1-3% of light)
If its true that only 1-3% of the light is absorbed by the plant then that means only 1-3% is transformed into heat. I know there are many different factors that go into a systems temperature (a tent), including EM spectrum, ballast location, hood vents & air circulation, material, strain, ect, so I have a hard time accepting someone saying something like all light eventually gets converted into heat or that its even a big enough of a phenomenon to test out, as I stated earlier Im confident the majority of heat is from other sources. But if you have anectdotal evidence and have noticed it's a big part of your heat battle then fair enough. Ill take your word for it.
 
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