PC Box Fan





Introduction: PC Box Fan

About: My name is Jason Poel Smith I am a Community Manager here at Instructables. In my free time, I am an Inventor, Maker, Hacker, Tinker, and all around Mad Genius

Whenever I upgrade a computer, I always try to salvage and reuse as many of the old parts that I can. One part that I have collected a lot of over the years is the cooling fan. You find these in power supplies, on CPU's and in tower cooling systems.

So what do you do with a bunch of small fans? You combine them into one big fan. In this project I take 16 PC cooling fans and mount them together to make a single 12 volt box fan. It is thin, light weight, strong, and quiet. It also stores easily. It can fit behind furniture or in a packed car. It can be powered by your computer's power supply, an AC adapter, or a 12 volt car battery.

Step 1: Watch the Video

Here is a video walkthrough of the project.

Step 2: Materials

Here are the tools and materials that you will need for this project.

16 PC cooling fans

60 Machines screws and nuts (small enough to fit the holes on the fans)

Wire (18 gauge or thicker)

Heat Shrink Tubing

Thin sheet metal

Hot glue gun and glue sticks

Drill ad bit set

Tin snips


Step 3: Collect the Fans

There are a lot of places where you can find PC cooling fans. There will be one or two inside the tower of a computer. There will be one or two in the power supply. There may also be a dedicated fan for the CPU but this will often be a different size.

But if you don't have a bunch of computers to take apart, you can also purchase them online for $1-$2. Check Amazon, ebay and the websites for big box stores.

PC fans come in a lot of different sizes. It doesn't matter what size you use as long as all the fans are the same size. I am using fans that are 80mm x 80mm x 25mm.

Step 4: Make the Brackets That Will Hold the Fans Together

There are a lot of ways that you could hold fans together. You could use glue, twist-ties, bent paper clips, zip ties, or magnets. In this example, I used metal brackets.

Here is an easy way to make some cheap metal brackets. Start by getting a thin piece of sheet metal. Then mark a grid on it with the lines spaced out as much as holes on the fan are when placed side by side. On an 80mm x 80mm fan, this will typically be 8.5mm (or about 5/16 inches) apart.

Then use a nail to punch a small hole at the points where the grid lines intersect. Then drill out these holes with a drill bit that is slightly larger than the machine screws that you are using. When drilling, make sure that the plate is held firmly in place. If it catches on the drill bit, it can spin around really fast and give you a nasty cut. I also recommend wearing gloves. After drilling the holes, you may want to use a file or pliers to remove any sharp burrs on the back side.

Lastly, use a pair of tin snips to cut out square sections of four holes. These will be the brackets that hold the fans together.

Step 5: Attach the Fans Together

Position four fans side by side. Fit a machine screw through the inside corner hole. Then place on the bracket and tighten a nut on the top. Do this for all four fans. Continue adding fans until they are all bolted together. The holes on the outer sides can either be left empty or held together with a half bracket (two holes). These can be made by simple cutting a four hole bracket in half.

Step 6: Connect the Wires

Now you need to connect the wires of the 16 fans. I started by connecting the positive wires of one row. Then I connected the negative wire of that row. Insulate each connection with either heat shrink tubing or electrical tape. Repeat this for each row. Now you have several sections of grouped wires. Lastly connect the groups of wires so that all the positive wires are connected together and all the negative wires are connected together. To test it out, connect the fan assembly to a large 12 volt battery. This should turn on all the fans.

Step 7: Glue Down the Wires

You don't want a lot of loose wires hanging around. The easiest way to deal with the wires is to use hot glue to hold them down to the body of the fan.

Pull the wires tight. Then put a large drop of hot glue in a corner of the fan. Hold the wires down on the glue until it cools and hardens. For large bunches of wires, you may want to put another drop of glue on top of the wires to help hold them in place. Do this for all the wires. Be very careful to keep the wires away from the fan blades. If the fan blades rub against a wire, it will not blow properly.

Step 8: Powering the Fan

A typical PC fan will run at 12 volts and 0.20 amps. So 16 fans combined will require 12 volts and about 3.2 amps. There are several ways that you can supply this.

The easiest way to power your fan is to hook it up to a large 12 volt battery such as a car battery. You can easily add a car power adapter plug to the end of the wires so that you can plug the fan directly into the cigarette lighter of your car or RV.

Another option is to use a computer power supply. You can hook it up to the power supply of your desktop and run the wires out of the back of your computer to the fan. You can also use an old power supply as a bench power supply and use that to power the fan. I also have a project that show how to set this up. https://www.instructables.com/id/Computer-Power-Sup...

You can also use a 12 volt AC adapter. I had a few old laptop power adapters that were able to power it. Just make sure that the adapter can output 12 volts and 3.2 amps.

Step 9: Enjoy You PC Box Fan

Now you can enjoy your new PC Box Fan. It works great. It's quiet. It is small enough to fit behind furniture or in a in a packed car.



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Very 'cool' idea :)

And if you use the 5 volt wire on your PSU then you can reduce the noise and yet still have a decent fan for hot days or when soldering etc :)

I like this one. Thanks for it :)

I know this is an old instructible now, but I have a question based on a project I'm thinking about utilizing PC fans.

What's the noise level like on this fan? As I know that sometimes PCs get loud, and I'd imagine that with 16 fans (more than I'm planning on using) it'd be unbearable in a small enough area that it'd be useful.

Also, what's the power consumption if you're using a PC power supply?

1 reply

It does make some noise. But it is significantly quieter than an regular box fan.

bro i think four fan for pc cabinet is ok...max to max 5....but this much fan !!!! The SMPS cant give that much power to run all these fans

Don't you need to add a capacitor to smooth out the voltage spike when you power all of them together?

3 replies

I'm thinking of building one... If a capacitor is needed, How is it possible to decide which capacitor (type/mf) to use? (Without an oscilloscope)

It needs to be atleast 12V, personally I would go with a 25V and the size, hust use "bigger is better"

First of all I love the concept but I don't know which cables to connect because my box fans have 3(Black,blue-not sure if the blue is for control of the fan,red) and you show how to make it with only 2(black,red). I plan to make 2 PC towers to the left and the right of my monitor to cool me off each tower will have 4 and each box fan requires .25 amps so that means 2 amps for both

1 reply

The red wire is positive. The black wire is negative. The third wire is for feedback to the computer. It typically sends a signal back to the motherboard to indicate the speed of the fan. That way the computer know if the fan is malfunctioning. You can just ignore this third wire and just connect the red and black wires as I describe in the procedure.


I have everything I need to make this(all be it on a much smaller scale), so it looks like I'm going to be busy for a wee bit! 8=D

TY for sharing this!

Took this idea with a usb cable to power 2 fans and it works like a charm, not to mention great portability.

The PC fans i salved from a old mac come with 3-pin & 4-pin with all grey wires which is hard to tell which ones positive or negative, help please?

1 reply

Just use trial and error. Hook it up to the power supply and if it is correct, it will blow. If not, just switch the wires.

I've got to ask. Are these fans wired in series of parallel?

1 reply

Hmmm, if you recycled the drive cage and maybe the corners from inside a case, you could build a pc case out of pc fans! Gamers delight!


Cool idea. I bet you could stick this fan array out in a stiff wind and it would charge a 12 volt battery or two. Nice 'ibble.

1 reply

To turn them into generators, would require stripping the pulse circuitry from the motor windings, re-wiring the coils like a 3-phase generator, and feed the voltage it creates through a diode bridge array (Nutshell response: Not practical.) (Note, Not impossible, just impractical.)