Computer Fan Wiring

raulhawkins718

raulhawkins718

Member
i have a sun systems 2 400 watt hps that has a place to hook up duct on the side and maybe the top too.....i have cool air running into my grow room through an 8" duct with a 200 cfm duct booster fan that spits air out about 18 inches from the ground which keeps the room around 73 - floor, 80 - 2 feet below light, over 90 - 4 inches below the light.....if i attach one of these cpu fans to the side of the light (screw or adhesive) just to blow some air around the bulb and then add another fan to the top to suck air up away from the lamp towards my exhaust duct, would that lower temps some?.....i read in an earlier post that these fans wont cool but perhaps i misunderstood.....im very interested in this concept because i am on a budget and am looking on surpluscenter.com at dc fans.....i believe i'll go to walmart and pick up an adapter.....thanks for any advice.....check out my grow journal to get a better idea of what my setup is if it helps any
 
Jackp0t08

Jackp0t08

Active Member
raulhawkins718 said:
i have a sun systems 2 400 watt hps that has a place to hook up duct on the side and maybe the top too.....i have cool air running into my grow room through an 8" duct with a 200 cfm duct booster fan that spits air out about 18 inches from the ground which keeps the room around 73 - floor, 80 - 2 feet below light, over 90 - 4 inches below the light.....if i attach one of these cpu fans to the side of the light (screw or adhesive) just to blow some air around the bulb and then add another fan to the top to suck air up away from the lamp towards my exhaust duct, would that lower temps some?.....i read in an earlier post that these fans wont cool but perhaps i misunderstood.....im very interested in this concept because i am on a budget and am looking on surpluscenter.com at dc fans.....i believe i'll go to walmart and pick up an adapter.....thanks for any advice.....check out my grow journal to get a better idea of what my setup is if it helps any
Click to expand...
It may not lower temps too much unless you are venting the air to somewhere, otherwise it will just move more heat away from the bulb
 
B

burn.after.rollin

Member
I'm making a grow closet, check out my post for a sketch...
https://www.rollitup.org/newbie-central/302667-first-grow-need-nutrient-vent.html
I want to use some computer fans for ventalation but I don't know how many to use. I was thinking 4. 2 intake at the bottom of the growcloset and 2 at the top for exhaust. Is this enough to keep me closet well ventilated? how many cfm will each intake fan need to move? I'm using a single 150 watt hps light so I don't think heat will be much of a problem.
 
S

Sice

Well-Known Member
If I need extra wire where can I get some?

I want to run 2 or 3 fans in my trash can grow but Im sure I will need extra cable to be able to power up the fans on the opposite side.

What type of wire works?
 
blatMachine

blatMachine

Member
The yellow wire is for PWM speed control. Unless you have a PWM driver hooked up to your fan DO NOT connect it. The red wire will be whatever voltage the fan is rated for, this is indicated on the fan label.

Also 2killspam; Voltage ratings ARE critical. If you go to the trouble of buying an expensive fan and ignore the voltage ratings you can significantly decrease the usable life of your fan. Technically you could use less voltage, but that is just inefficient because the fan will not rotate at rated speed.
 
gotdank

gotdank

Member
Just to clarify on a molex power cord the yellow is the 12v and the red is the 5v power, the two blacks are the ground. The Fan it self has different wiring and usually the yellow is speed control red is hot and brown/black is the ground.

THE VOLTAGE DOES MATTER!!! and so does the Amps being used by your fans in TOTAL. my fans use 0.53A I have 3 powered by a 5A molex power adapter.

DO NOT THINK THE EXTA .03 DOESNT MATTER, if you have a 2 amp power source and you hook 4 0.53A PC fans up expect failure and possibly fire.

 
MMAFanatic

MMAFanatic

Active Member
Ok I am confused I have a red wire which i assume is Positive and Black wire which I am assumming is neg what is the white wire ?
 
P

paOol

Member
is it just me, or are these fans severely underpowered?

i have tried 3 different cell phone chargers,
one of them is a charger that u plug a usb cable into.

i have also tried 3 different fans, 2 of them are unknown cfm but also like 7 years old, so i know they're not that great.
i bought a 65 cfm fan today and it doesn't seem that much stronger.

is it the chargers im using? or is this method just always going to be weaker than compared to if the fans were connected to a computer's power supply
 
Me Gusta

Me Gusta

Member
just did this. worked! seems like its not gonna be enough CFM though. im gonna get a rough estimate of the CFM of two of these running inline. ill let you guys know how it goes
 
A

Alabaster Jones

Member
Check your fans wattage and amperage if you're using surplus chargers. You want the wattage to match up and the amperage at or somewhat over the fans requirement.

Cheap and/or used chargers can be a real fire hazard,so use a quality one.
 
G

guitarguy10

Well-Known Member
For anyone looking for a GOOD (and CHEAP) PC fan, look for:

Skythe Ultra Kaze (High Static Pressure) 120mM

133.6 CFM !
3000RPM
46DBA

$8 each on NCIX (I don't work for em, they just have em cheap).

These fans are great, if not loud though, but if you want 133CFM from a PC fan I guess loud comes with the territory
 
Rokynutz

Rokynutz

Active Member
Thank You MMAfan and all others for various input on this topic, for i have been wondering how you wired them. I was thinking you just pu a PC power supply up with your other ballasts.
 
UKHG

UKHG

Well-Known Member
y not just sabotage a pc power supply then u got moelx to as many fans as u want?
 
TechnoMage

TechnoMage

Well-Known Member
UKRG said:
y not just sabotage a pc power supply then u got moelx to as many fans as u want?
Click to expand...
Because the power supply won't work unless the main power line is plugged into a motherboard or you jumper some pins to make the power supply believe it's plugged in.
 
MarioMadness

MarioMadness

Active Member
Connect any of the black wires to the only green wire on the 20-24-pin connector that goes to the motherboard and it will start up
It will act as a jumper and make it so you need no PC to use the power supply. This Is how I wired all my fans.. for the quick connector and multi- fans and digital temp gagues outside of my box.. Also The power supply has surge protection, for extra protecting!

atx-power-bypass.jpg

Wire them together for better safety! But it cannot cause a short out or error.. the wires are basicly just to turn on the power supply

8atxstecker20pin8zs.gif
 
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