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Growing Under LEDs at Temps Above 80F

f-e

f-e

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mojave green said:
Watts are watts in regards to heat radiated by light fixtures. The heat comes from the bulb and the ballast with HID. The heat from LED’s is largely from the drivers, with LED’s themselves adding the rest. Still, if you run 500W HID, or 500W LED, heat output remains same. Good discussion.
Click to expand...

I forget the exact numbers, but 90% of the power going into a 6 becomes heat, and about half of that leaves as IR radiation. The LED turns about 70% of it's power consumption into heat. Most of which leaves by convection.

This makes putting your hand under a HID unbearably hot at distances you can't really feel anything under the same powered LED
 
Koondense

Koondense

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mojave green said:
Watts are watts in regards to heat radiated by light fixtures. The heat comes from the bulb and the ballast with HID. The heat from LED’s is largely from the drivers, with LED’s themselves adding the rest. Still, if you run 500W HID, or 500W LED, heat output remains same. Good discussion.
Click to expand...


I find this way too simplistic, while i agree in part.

If it were true there would not be a need for hids or other kinds of illumination. Par turns to biomass which turns to heat only when you burn your weed.



Cheers
 
C

Cheedale

New member
This is very interesting thanks! I’m
goung to raise the temps a bit in my room.

Do you think the temperature was the ambient room temp or the leaf surface temperature? There’s normally around 2.8 degrees centigrade difference.
 
indagroove

indagroove

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mojave green said:
Watts are watts in regards to heat radiated by light fixtures. The heat comes from the bulb and the ballast with HID. The heat from LED’s is largely from the drivers, with LED’s themselves adding the rest. Still, if you run 500W HID, or 500W LED, heat output remains same. Good discussion.
Click to expand...

So what happens when you run a 500watt refrigerator with the door open in an enclosed room? Sure those 500watts are converted to btu's based on the standard conversion, but there was also all that cold that the watts produced. The watts to btu conversion is only part of the story.
 
GMT

GMT

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I used to struggle to keep a 400w HPS cool. Now I can run 600w of LED in the same space without a problem. Heat production between HPS and LED is not the same.
 
mojave green

mojave green

rockin in the free world
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I’m gonna say this and leave it alone:
1 W is equal to 3.41 BTU/h.
Google it if ya don’t believe me.:tiphat:
 
f-e

f-e

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Just floats up and away..
I assist the convection currents with little fans but my extract is 29c and the canopy 25c. I don't think I ever had canopy temps below the extract temps when using HIDs and I air cooled them at times. The problem is that half the power is radiated and only about 30% heats up the air making extraction possible. I even water cooled and despite the science, I had damp wood steaming. I had placed two bits from the cellar across a bucket and rested the tube upon them looking for leaks. I thought I had one as it was soon steaming.

That is 600w per meter. No fannying around. Nothing over 50c
 
f-e

f-e

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mojave green said:
I’m gonna say this and leave it alone:
1 W is equal to 3.41 BTU/h.
Google it if ya don’t believe me.:tiphat:
Click to expand...

1w if turned to heat with 100% efficiency.

Leds loose about 30% to light production. HIDs 10%.
Leds heat leaves mostly by warming the air around them. HID's radiate heat.

It's a totally different game
 
SuperBadGrower

SuperBadGrower

Active member
All that % talk is mumbo jumbo. Here's the real deal holyfield. HID makes light by heating shit up to thousands of degrees and diodes don't. I think once you come to terms with that, it's easy to see how HID lights heat up a room better than LEDs. Theres a lot of debate about this but here is some real experience. Just last week I replaced a 320 w led with a CMH in a super cold room where some plants were almost dying from low temperatures. The radiant heat from the HID light absolutely saved them. The only other option is to run a 1kW electric heater. easy choice. Trust me lol that 320 w led has NO HOPE of even warming up that room. Run it at full power there's too much light and too low temperature. Maybe the HLG driver can warm your hands. You walk in there and it's like 68 F on a good day. Run it at 50% there's little light and you looking at a 62 F room full of yellow leaves and purple stems. Now I walk in there today just 2 days after hanging CMH and the whole room feels like a nice pleasant warm day (about 75-77 F). Great health and everything is greened up. On schedule for cloning. I do this year after year after year after year
 
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indagroove

indagroove

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I understand that a watt = 3.4 btu's no matter how you slice it, but I think one thing that's left out of that equation is what those watts have been converted to. Everyone loves to say that a 500w refrigerator burns the same watts as a 500w heater, but what about the product of those watts? I think we have to consider that if we left the refrigerator door open there would be some cooling introduced to the room as a byproduct of the watts' consumption, and conversely with the heater we would have additional heat as a byproduct, so the heater side should be overall warmer than the refrigerator side. This is also how I see HID lights vs LED. The fact is that there's a pretty huge IR spike around 820nm from most HID lamps, which could account for up to 20% of the power consumed by the lamp. IR is basically heat, which in this case is being radiated in a directed way towards the canopy of plants. In my opinion, this is why most growers do experience the real situation of LED grows being different than HID grows, despite the science of 1 watt = 3.4 btu's.
 
Fixer

Fixer

Active member
Great discussion! Before I went all LED I had two 1000W DE fixtures over one 4x8 flood table. The 4x8 table next to it was lit by two FGI 640W LED panels. I had great results under the LEDs. I kept the room at 76F-80F


I've now got the room at 83F at the moment. Let's see if the first LED table produces the same results without the HPS light over the table next to it.Thanks for the knowledge!
 
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Fixer

Fixer

Active member
Any recommendations for an accurate heating solution in the grow room. I have an oil filled space heater going but it's thermostat is crap. I can't dial it in.
 
Fixer

Fixer

Active member
I have considered jerry rigging one of the HPS fixtures I just retired. I wonder if the bulb turning off and on would be detrimental to the plants? I don't imagine it would, Although I'm often wrong.
 
mojave green

mojave green

rockin in the free world
Veteran
Fixer said:
I have considered jerry rigging one of the HPS fixtures I just retired. I wonder if the bulb turning off and on would be detrimental to the plants? I don't imagine it would, Although I'm often wrong.
Click to expand...
You don’t want lights coming on in the dark cycle.
 
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