Wiring a PC fan

Hi guys. I'm building a small flower cab and I'm going to be using a couple of 120mm PC case fans for ventilation. I'm curious if anybody has a good link with instructions for wiring. OR if someone can just answer for me whether PC fans run on 12v or 5v... then I can probably figure it out. Also - do you think that 2 110 CFM fans will work for a cab that's roughly 20"x30"x48"? Should I use one for intake and one exhaust or both for exhaust and use a passive intake? thanks!

I use a pc fan from radio shack that runs on AC current. So all I had to do was wire a plug-in to it. Most people don't know radio shack sells these.

2 fans may be suffucient, but it depends on how many lightbulbs you will be running. i built a custom enclosure for my lights with a 96cfm fan pulling heat from the bulbs and temps went down 6 or 7 degrees f. i also have 2 more 96cfm fans that i use as intake and exhaust. works fine. my flower cabinet is 18x30x48.

the pc fan should have a label/stamp on it that states how many volts it is. either way it will run off of both, if 5v seems too slow then try 12v but keep an eye on it to make sure its doesnt burn out.

look for fans that are ac power not dc power, its much easier.

right now I have 5 43w CFLs but I'll have up to 7 or 8 during flower. What do you think, 1 in 1 out or 2 out, passive in? Oh and anywhere from 1-3 plants depending on what sexes I end up with

all you need is a cord from a charger or anything that has a box like thing that plugs into the wall and with that you can run a pc fan on a wall socket. anything else will fry the fan.

JustAnotherNewb said:

Hi guys. I'm building a small flower cab and I'm going to be using a couple of 120mm PC case fans for ventilation. I'm curious if anybody has a good link with instructions for wiring. OR if someone can just answer for me whether PC fans run on 12v or 5v... then I can probably figure it out. Also - do you think that 2 110 CFM fans will work for a cab that's roughly 20"x30"x48"? Should I use one for intake and one exhaust or both for exhaust and use a passive intake? thanks!

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The fans will work on either 12v or 5v. A PC power supply supplies 3 different voltages. 12v, 5v, and 3.3v. The lower the voltage supplied to the fan the slower the blades will spin. Which means the slower the blades spin the less CFM moved and hotter your box. I recommend buying a 12v printer power cord from newegg. it will convert straight 120DC to 12v AC. I got mine for like 12 bucks and run 10 80mm pc fans off it. Cut the end off to wire the fans in. Just make sure the ampierage of of the printer cable is higher than the amps of all your fans combined that are connected to it, your good. And it has to be 12v as well.

Good luck.

I aint a expert but this is how I got mine. Go to a old computer open it up find the fan and it may SLIDE out, if not just screw it out. Now thats done and you have the fan in your hand snip the end of the wire were the thing connects to the motherboard. You'll probably have 3 wires or 4. The ones your looking for are the RED and BLACK. Get a cell phone charger and snip the end that plugs into the phone off now split it like a banana a inch or so down to handle and strip the wires a inch. Strip the red and black wires from the fan and twist the exposed wires together. If it doesn't work then switch it around. MAKE SURE the exposed wires are not touching like i mean don't get the two wires that are now connected touching each other because that breaks the current. Once you have it all figured get some electrical tape and wrap the exposed wires up and your good to go. If you don't have a spare phone charger you can always use a 12V AC adapter.

Good Luck

Look, I have a degree in Information Technology. The standard, cheap, pc fan usually only has 2 wires, maybe 3. Red and black. Black is ground and red is hot obviously. You can use a cell phone charger is it says Output: 12.0VDC. I searched through 4 different chargers I had and none were 12. The highest voltage charger out of 4 different phone chargers was 6.8. When you supply a lower voltage than 12v to a pc fan, it runs at a slower speed. So if it was getting 6.8v than it is moving half the amount of air it could. I mean as long as its 12v changer than you good. You also have to take into account how many fans your going to be running off the one power unit/charger. Most 80mm PC fans use .25Amps. Look at the Amps the charger says it has. Mine says .7Amps. That means, if a fan uses .25 and the charger only has .7 than that leaves only .45amps left. You could run a total of 2 fans off this charger, if you ran 3 fans at even .75 amps, .05 over the .7 limit, it prolly would either break/fry/spark the charger. Never tried it. And if by some miracle it does work, its a huge fire risk.

Trust me. Just go on newegg.com and find a printer power cord thats 12v and like 5amps for 10 bucks total. Your can run as many fans you need off of one unit. If your going to do something, do it right, not half assed. As you will learn with horticulture, that is pretty much one of the main golden rules.

Red is 12v, Black is GND (Ground) and Yellow is 5v.

Most fans have 3 wires, with those colours, some have 2 (Red/Black) and some may have a 4 Pin Molex with 2 wires shared to a 3 Pin Header (Just for compatibility on certain Motherboards, or to power via a PSU instead.

If the fan has those extra connectors, just cut them off, or if your handy at some DIY, use them with a modified ATX PSU.

I have never seen a 12v phone charger, generally round 5v-7 which wont be enough.

As the other have said, check the label of the fan, and determine what you will need. A 12v DC charger for a camera, ect will be good, and normally the wires will have white text on one and a white line on the other. The white line is GND. Or make one your self, pretty easy.

souldevour said:

Red is 12v, Black is GND (Ground) and Yellow is 5v.

Most fans have 3 wires, with those colours, some have 2 (Red/Black) and some may have a 4 Pin Molex with 2 wires shared to a 3 Pin Header (Just for compatibility on certain Motherboards, or to power via a PSU instead.

If the fan has those extra connectors, just cut them off, or if your handy at some DIY, use them with a modified ATX PSU.

I have never seen a 12v phone charger, generally round 5v-7 which wont be enough.

As the other have said, check the label of the fan, and determine what you will need. A 12v DC charger for a camera, ect will be good, and normally the wires will have white text on one and a white line on the other. The white line is GND. Or make one your self, pretty easy.

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Exactly, Right on. If the fan has 3 wires, the yellow/blue in my case 5v wire just connect to the power and it will work fine. Intelligence is key, ignorance is bliss.