92+ degrees in a 2x4x5... With LEDS?(19% RH)

Mgalekgolo

Active Member
The whole "LEDs don't produce heat" thing is obviously not true, I knew that when I got the lights. However, I purchased 2x 1000w(185 true watt) BESTVA full spectrum LEDs. Ambient temps outside the tent, around 70 degrees with ~55% rh. Current airflow is from one clip on fan and an inline fan for exhaust. In the tent, with the lights on it's currently 95 degrees with 19% RH (with a fogger and bowl of water) which is obviously unsuitable for cannabis growing. What choices do I have, without buying an AC or something that'll take up too much space?
 

Renfro

Well-Known Member
What type of exhaust fan are you running?

Do you have passive intakes? Are they low?

What is the ambient temperature (outside the tent)?
 

Renfro

Well-Known Member
You won't be able to bump up the humidity much while venting the tent as you are removing the humidity as fast as you can make it. A larger humidifier outside the tent may help more by bringing the ambient RH up.
 

Renfro

Well-Known Member
Inline mixed flow fans don't do well. Centrifugal is the way to go, but they are loud. You want your exhaust up high and the passive intakes down low. Passive intakes should have a surface area of 2x the exhaust.
 

Mgalekgolo

Active Member
Sorry for not giving you guys the information -
It's a 65CFM Ducting fan,
I had tested my 190CFM inline fan I'm using for my other tent but it didn't seem to make a difference.
Tent is a 2x4x5
Side flap is open, seems to help.
Exhaust exits from the top, from my understanding that's where I want it. Passive intake is from the bottom.
Ambient temp is 71 degrees with 55% RH
 

Precaution

Active Member
I hate to tell you but, IMHO, that Duct fan isn't gonna do much. I did the same in my 2x4 with heat producing LED's and bad fans to.
I bit the bullet and went QB's and centrifugal fans and am much happier.
Maybe keep the tent door open a bit to? I had to do that for a bit also.
 

Mgalekgolo

Active Member
Trust me I'm gonna return the damn thing.
I had a 600W MH in a vented hood setup before I switched that to my flowering tent. Temps there were very stable at 70night-82day with 60%RH with a humidifier, probably 30% without. I might just return these LEDs and get another MH/HPS setup, but I really like the idea of the LEDs.
Here's a link to the lights: https://www.amazon.com/gp/product/B01871AHTC/
Seemed to have good reviews, I'm not the only one to complain of heat issues though. My 4x4x7 tent keeps in humidity and heat well, to the point where I don't really need a humidifier in there and I run the inline fan at the lowest setting.
 

Mgalekgolo

Active Member
Would you mind linking me to the QB you purchased? I dropped ~600 on these LEDs already so if I return them I don't mind reinvesting.

Edit:
I'm pretty new to LEDs, and I was hoping to match the 600W HPS power which is why I went with 2 185Ws. With just one, the temps are manageable and humidity is good, but I'm planning on growing a Purple Haze x Malwai strain, I need a lot of light for that Sativa. Any firsthand knowledge is greatly appreciated, bear with me I'm very new to this shit.
 
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growingforfun

Well-Known Member
Would you mind linking me to the QB you purchased? I dropped ~600 on these LEDs already so if I return them I don't mind reinvesting.

Edit:
I'm pretty new to LEDs, and I was hoping to match the 600W HPS power which is why I went with 2 185Ws. With just one, the temps are manageable and humidity is good, but I'm planning on growing a Purple Haze x Malwai strain, I need a lot of light for that Sativa. Any firsthand knowledge is greatly appreciated, bear with me I'm very new to this shit.
You'll learn the LEDs dont make as much heat story is a complete lie. A watt is a watt and it doesnt matter what is consuming it they produce the same heat. Sometimes it's much easier to manage the heat with traditional HID lighting because the heat can be simply ducted away...
Other times people can manage the heat better with cutting edge led because they are running 2/3rd the total watts and they never learned how to connect ducting to a vented hood.
Youll honestly learn that more than half the LED users never learned how to use HID lighting. Some did, but many did not.
 

Precaution

Active Member
I only grow in a 2x4 and 3x3, depending. I currently am running 4 QB 120 and they do ok but not Great. I plan on getting a 315w CMH next month and use the QB's for veg or side lighting.
If I were to do it over I would have gotten the 2 QB 288's for the 2x4 and CMH for the 3x3. But that's me. I am new also with only a few years growing and am still learning.
My plan is to get away from LED's all together. They are just not for me.
 

Mgalekgolo

Active Member
So, I want to use this 2x4 for Veg, but I will be growing 3 autos which I'm gonna leave in the veg tent. If I understand correctly, I'm gonna be better off just buying another 600W HPS and centrifugal fan? I'm willing to drop the money on a CXB3590 with the HLG-480H-C2100B driver, but if the HPS will outperform it then I'm gonna go with that. Thanks for your input guys.
Long term electric costs are also a consideration.
 

growingforfun

Well-Known Member
I only grow in a 2x4 and 3x3, depending. I currently am running 4 QB 120 and they do ok but not Great. I plan on getting a 315w CMH next month and use the QB's for veg or side lighting.
If I were to do it over I would have gotten the 2 QB 288's for the 2x4 and CMH for the 3x3. But that's me. I am new also with only a few years growing and am still learning.
My plan is to get away from LED's all together. They are just not for me.
I really wanted the 288s for a while too. The price never made since to me though as I got into the final stages of planning. I know some people have outstanding results with them and are able to do it for a price that makes sence to them.
 

growingforfun

Well-Known Member
So, I want to use this 2x4 for Veg, but I will be growing 3 autos which I'm gonna leave in the veg tent. If I understand correctly, I'm gonna be better off just buying another 600W HPS and centrifugal fan? I'm willing to drop the money on a CXB3590 with the HLG-480H-C2100B driver, but if the HPS will outperform it then I'm gonna go with that. Thanks for your input guys.
Long term electric costs are also a consideration.
Long term electric costs are something to keep in mind... how much are you paying for electric? That's a very important thing to know. I personally pay about 8 cents per kilowatt hour. That means 24x.08= 1.98 per day per 1000 watts., aka about 60 bucks a month per 1000 watt light if I run them 24/7. In flower that's 30 bucks a month per 1000 watts. For a 600 watt light thats 36 bucks a month.

I personally believe people vastly exaggerate the cost of lighting... but that's just me.

Things to concider... removing your heater and connecting your ducting from your lights to your home heating in the winter. Basically making it give you free garden all winter.

Depending how you set things up HID growing can be very cheap and the heat is easy to move to where you want it...

My personal electric bill running 3kw is STILL less than my neighbors electric bill because they spend so much on electric heat. Typical home heating systems just arnt as good at moving heat where you want it as what we build.. not many homes are built with 8 inch duct fans that move 750 cfm.
 

Mgalekgolo

Active Member
Right, I believe it's more like 20 cents per KWh here, I'm jealous. It's also in the high 10s, low 20s(Fahrenheit) in my area right now, and we use radiators for heat, so with 2 600W lights I don't really produce enough heat to warm the house. I think I'll just get another 600W MH and exhaust the heat into the house like I've been doing, really wish those LEDs would work out though.
Brings me back to humidity, though. I'm gonna be using fabric smartpots which I hear raise humidity, but I always had to use a humidifier even with well vented grow lighting. Pain in the ass to fill every day and if I want to leave for a couple days I come back to a grow tent with a RH around 30%.
 
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