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CFLs and Temps. many low-wattage or fewer high-wattage?

q3corn

q3corn

Active member
So recently I built my first micro-cab, internal dimensions of 13"d x 20"w x 22" t. in it I have 3 68w cfl's, a 4" duct fan (for exhaust) and an 8" carbon scrubber to go with that. intake is 3 3" duct pipes, two of which have 80mm pc fans pulling air in. I also have a 120mm pc fan facing the bulbs to help move air.

now for my problem. it seems that with only one bulb on, my cabinet gets up to about 12 degrees F above the ambient temperature around it. With two, it goes up over 20F, and with three, I've not kept them on long enough to see. My house (and room that this cab is in) sits around 72. As of right now I've only been using one light to help with my seedlings. 68w for 10 seedlings is certainly enough. However, when they get bigger, I'm going to have to either find a new way to cool the cab, or change my lighting, which really is the only heat source.

I got the 68w cfls because they were a good deal for the amount of space they took up. I figured fewer bulbs would be better. Now I'm wondering: should I instead change for many smaller cfl bulbs? perhaps 6x 26w or so? Or is my temperature problem going to exist with other lights, and maybe I need to revise my fan situation?

Thanks for the help! Hope to figure this out!
 
q3corn

q3corn

Active member
Also quick ad:

I originally had passive intake, but thought that attaching the pc fans to the intake would help force cooler air into the cab faster. Is that a waste of the fans?
 
TexMex McDirt

TexMex McDirt

Active member
While CFLs may not put out the heat of HID, they sure do put out heat. If you're having heat issues now with only 1 or 2 68w CFLs, I don't think choosing between those or more lower watt bulbs will be the answer. Ventilation can be a bitch to get right in a micro grow, but is one of the most important pieces to dial in for success. You might try a few lower watt bulbs and see what happens with that, but my guess is your fan isn't pulling thru the carbon filter efficiently enough to keep it cool. If you're not in flower yet you might try taking out the scrubber to see what that does. I'm betting you need a better, stronger fan.

Happy Farming, Stay Safe!
Tex
 
q3corn

q3corn

Active member
Tex made a good guess, so i pulled the carbon scrubber out of line, and with two bulbs we're sitting at 85F with no other changes!

So i guess i can do a few things: get a new exhaust fan that pulls more, or get a less restrictive carbon scrubber.

In the name of small-scale, what do you guys suggest? I'm not worried about stealth, but a noisier fan might be less fun to hang around
 
HuffnPufferfish

HuffnPufferfish

Member
more surface area to filter will decrease airspeed (less noise) but if you need to buy a bigger filter it might not be worht the costs
 
Dion

Dion

Active member
TexMex McDirt said:
While CFLs may not put out the heat of HID, they sure do put out heat. If you're having heat issues now with only 1 or 2 68w CFLs, I don't think choosing between those or more lower watt bulbs will be the answer. Ventilation can be a bitch to get right in a micro grow, but is one of the most important pieces to dial in for success. You might try a few lower watt bulbs and see what happens with that, but my guess is your fan isn't pulling thru the carbon filter efficiently enough to keep it cool. If you're not in flower yet you might try taking out the scrubber to see what that does. I'm betting you need a better, stronger fan.

Happy Farming, Stay Safe!
Tex
Click to expand...

:yeahthats
 
Jellyfish

Jellyfish

Invertebrata Inebriata
Veteran
In my experience, the ones that are around 43 watts worked out the best for optimal light versus the issue of heat.
 
amanda88

amanda88

Well-known member
q3corn said:
Also quick ad:

I originally had passive intake, but thought that attaching the pc fans to the intake would help force cooler air into the cab faster. Is that a waste of the fans?
Click to expand...

I'd stay passive, but this is a lot of work for maybe one toke of weed?
 
Dion

Dion

Active member
q3corn said:
Tex made a good guess, so i pulled the carbon scrubber out of line, and with two bulbs we're sitting at 85F with no other changes!

So i guess i can do a few things: get a new exhaust fan that pulls more, or get a less restrictive carbon scrubber.

In the name of small-scale, what do you guys suggest? I'm not worried about stealth, but a noisier fan might be less fun to hang around
Click to expand...
https://www.icmag.com/ic/showpost.php?p=7222790&postcount=21
 
q3corn

q3corn

Active member
Ok, this thread that blynx did comparing CFL and LED light output (https://www.icmag.com/ic/showthread.php?t=314806) really got me motivated, so I grabbed a few different Phillips 14w LEDs, one at 2700k and one at 5000k. After I got the top casings off (just needed a blade to cut through the plastic), I plugged them in next to each other to see if there was any difference. Outside of the visual spectrum difference, I realized the 5000k was MUCH cooler than the 2700k. Also, neither of them have the Lumen output that 68w cfls have, but as blynx showed us, they have a much stronger lux output in comparison to their lumens. Also of note, the 2700k LED was actually hotter to the touch than the CFL coils! I'm wondering if maybe there's a reason...

So my cab has changed considerably. I have moved all the bulbs up higher, and added (so far) one LED bulb, 14w 5000k. I took all the intake fans off and moved them around the cab, facing the bulbs, too. After switching it to 2x 68w cfl and 1 14w LED, the temperatures are at a stable 85, which is really only about 8 degrees warmer than the ambient temperature of the house these days.

Seems my temperature problems were solved by switching to LEDs, just like Dion suggested! Thanks, guys! I'm excited to be a part of this micro-community
 
q3corn

q3corn

Active member
Jellyfish said:
If you're not worried about stealth, why not put everything in a bigger box?
Click to expand...

Stealth and limited space available are slightly different :) I can have a big carbon scrubber, or a loud fan, or a bit of an odor, but I don't have more than 3 square feet available
 
T

thesloppy

Jellyfish said:
In my experience, the ones that are around 43 watts worked out the best for optimal light versus the issue of heat.
Click to expand...

I've had the same experience, for whatever that's worth. I can comfortably rest my hand against a ~45 watt bulb, whereas anything above that wattage feels noticeably hotter.

I've been using these, because I'm a cheap ass:

http://amzn.com/B00947QMK2
 
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