Upcycle your old PC fans into mini wind generators

Have stacks of old computer equipment gather dust ? Now you can put some of it to use! This instructable shows you how to use PC fans as mini wind generators for recharging solar lights and ni-cads. You'll need some basic soldering skills, but this is otherwise a very easy project. My little wind generator makes around 1.5 - 2V in a 8mph wind, about 20ma into a ni-cad. This wasn't a huge success, I'd hoped to get a little more power out of it.

Materials needed:

Thick plastic bottle.
Old PC fan, bigger the better!
A few feet of small wire
A piece of wood about 1.5" square and around 20cm long
Two lengths of steel tubing that slide inside of each other, about 1/2"
4 Schottky diodes, I used BAT85 but any will do
Epoxy
Super Glue.
Zip ties
An old CD

*** Update 26/06/10 It was pointed out to me that the wiring isn't quite right, I had assumed that the 3 legs of the coils are three phase (I don't know why I did!) but it's actually just a centre tap. I've photo-shopped the photo's so that the new wiring makes sense, so if the photo's look dubious, that's why! Thanks Culturespy

Step 1 Dismantle your PC fan

Normally these fans are held together by a little circlip. This is hidden under a seal on the back of the fan. Remove the sticker, and prise the little rubber seal off. This should reveal the circlip, you can prise this off with a little screw driver. You should be able to pull the blades off now.

Comments

[zigzagchris]

My fan says its allready dc so does that meen i need the alternator?

[scraptopower]

No, all PC fans are DC. Follow the instructions and it will work :)

[dasimpson1981]

the 4 pole ones are not 3 phase the 6 ones tend to be thor this you would need 2 full brudge rectifires or a full bridge and a half bridge

[scraptopower]

You're right, I think. I confused myself a lot with this one because, I was working with a few different types of fan. Hope I got everything right though!

[dasimpson1981]

well i have just done a 4 pole my self just now and what you said works well i got my bridge rectifire from a dead pc psu as well as the fan

but the other fan i have has no poles just a big ring with 2 coils on so did the same for that and works also

3 phase gets more fun lol you need to decide if you going to use star or delta i can not remeber what one is best

[dasimpson1981]

delta is the best the voltage stays the same but the ampage is higher
star voltage is higher ampage is the same

[dasimpson1981]

why do you have 3 wires on the fan your using as an alternator.
when you have said to only solder 2 in your instructable

[scraptopower]

"Update 26/06/10 It was pointed out to me that the wiring isn't quite right, I had assumed that the 3 legs of the coils are three phase (I don't know why I did!) but it's actually just a centre tap. I've photo-shopped the photo's so that the new wiring makes sense, so if the photo's look dubious, that's why!"

I changed it because I got it wrong.

[dasimpson1981]

technicly it is 2 phase
you have a coice more voltage or more ampage.
to charge a 1.5 volt battery you need at least 2-2.4 volts.
so this way if you mark the leads you can decid if you wont more voltage or ampage

[NunamedDragon]

Nice idea, but i cheated with the blades as i used spare blades from a RC helicopter

[scraptopower]

That's not cheating, that's progress!

[eyas.fazul]

I dont understand step two properly, could some1 explain!

[mroy9]

Is it not possible to use an incandescent electric bulb instead of an LED Bulb so as to skip this test. I think most incandescent bulbs work on AC.

[jamiemacko]

i'm kinda new to this. my box has a "DO NOT OPEN DUE TO RISK OF ELECTRICK SHOCH" should i open it or not

[seraine]

If it is a fan, you shouldn't have anything to worry about.

[sanjeshnz]

Awesome. Thanks for this! I was going to turn an old pc fan I found in a charity barn into a little wind vane/anemometer thingy but now Im going to add electricity to it and have some LEDs running on it too - if is all works that is! :-)

[jmarcelo]

I've already finished the model,now,how can I charge using it?can you please post some picture or some guides?thanks for the help!Im just a beginner.Thanks

[paul76]

can i ask why you removed the old wires and replaced them?

and excuse my noobness but wouldn't a battery make the motor spin and drain a battery rather than charge it??

[TheBookworm]

can I use a prebuilt rectifier?

[benji.abrams]

this is my version of your Mini Wind Generator build by your instructions + a Way to get the electricity down without stopping the 360 movment

[27ace27]

I'm pretty sure this also works with brushless RC plane motors, but they're a lot easier as they aren't in a case and already have the 3 leads from the coils. I'm not entirely sure, but I have a spare and I'm going to give it a try!

[cardo218]

Can you remove the copper coils and add different coils such as gold or aluminum ? Just out of curiosity so that maybe i can get more power out of a better conductor >:D

[scraptopower]

if you have an infinite amount of patience you can :D

[cardo218]

What do you mean by that?
Cant i just buy already made coils and replace them?

[Gambit510]

I can't tell which two coil legs I should solder the wires onto, there are 3 legs that look exactly the same to me.

[scraptopower]

One of the legs will have two wires twisted onto it don't use that one.
Or you can check the resistance between the legs, the two with the highest resistance will be the ones you want.

[Amar143institute]

Great , But Minor Power Will be Genenerated

[baven]

mine is generating only 0,1 volts did i something wrong?

[wesdom]

Thanks for the instructable. Got it working, but left the fan as is and stuck it over my AC. It worked like a top and lit the LED. Not sure how fast the fan was running but it was going pretty fast.

Not understanding much. I was thinking my ac is creating a lot of wasted energy.

Can I make a series of fans having their wires combine and raise the ampage?

Like 1 fan push 1.5 amps. 2 fans = 3 amps.

[jimbo13]

i connected a piezo buzzer directly to a pc fan and it works as a wind alarm, the faster the wind the louder it gets.

[rajat s d]

how much elec. does it produce please tell me

[CaptainPatent]

assuming the blades are half a foot long, in 10mph winds, the maximum amount of power this would produce is around 2.39 Watts.

I'm guessing that because the fan motor is a bit inefficient at lower and higher speeds and the blades are probably a bit more inefficient than fiberglass cast or wood carved blades, the actual output is probably something like this:

5mph = 0.1 Watts
7.5mph = .3 Watts
10mph = .8 Watts
15mph = 2.7 Watts
20 mph = 4 - 6 Watts (depending on the fan size)

Most PC fans are rated at 2-10 Watts so you won't get too much more electricity back out of them than that without causing some damage.

Most also spin at 600 - 1500 RPMs and most of the time, you won't see more than 400 RPM out of a wind turbine.

This is more of a "toy" setup than an actual utility electricity generating unit. If you know what you're doing with a circuit board and a soldering iron, you may be able to charge a bank of batteries (a typical NiMH battery requires 1.2V at .075A for around 14 hours (only about .09 watts each) so if you can make a good regulator and properly dump any extra voltage, you may be able to charge 2-6 batteries if you get a constant wind.

[voyteck]

Congratulations for this clever idea, i have made two of these but some questions have reached my mind, how can you make an array of these pc fans to get a high output? I'm thinking on using them for some garden lights, but i want to know how to connect two fans outlets.

[jlopez felizzola]

depends on what you are looking for, if you want more Voltaje (to power a bigger LED) series is the way to go,

|
FAN_out
|
FAN_out
|
FAN_out


but if you want Current (to power many small LEDs) id recommend parallel configuration,
______________
| | |
FAN FAN FAN ...
__|___|____|___


plus, It is a good idea to add a capacitor to the output of the rectifier to reduce the curl (which is a good idea since many people are thinking of charging an iPod or things like that with this)

[ddavis662]

Your small motors probably produce more power than my larger motors :)
http://www.instructables.com/id/Small-Wind-Powered-Generator/
It's still fun just to tinker around with them. I'm going to give your istructables a try ASAP

[Geeko]

How could use this to charge AA batteries? Is there anything I would need to worry about?

[mmorrissette]

mine only does 0.2 volt

[scraptopower]

You must have something wired wrong .

[mmorrissette]

I think that my fan was broken so i've replaced it with a small dc motor that can does 6 volt by spinning the shaft by my fingers.

[seekanddestroy]

I'm thinking of taking a car alternator to make a generator out of that do think that would work i have literally 5 good ones