Bicycle Cell Phone Charger (Wind Turbine With Build in Battery)





Introduction: Bicycle Cell Phone Charger (Wind Turbine With Build in Battery)

About: Hi, I'm Tamas (Thomas), a 19 years old Hungarian guy. My hobby started more than 10 years ago. I learn electronics, physics, programming, IoT and I'm sharing my projects with you, hope you like it!

I go very often to cycle in the nature where is no electricity, and during a long bike tour my phone usually discharges. These smartphones have a large capacity but its consumption is big too. I made a few weeks ago another bike turbine for the Bicycle Contest, but I think I can make a better one. So created an all in one wind turbine power bank.

I like to combine cycling with electronics (these are my favorite hobbies) so that's why I create so much bike gadgets now for the Bike Contest.

This project requires basic soldering experience and some patience.

The price of a device like this is very high on the eBay, 112 bucks!!! Click here if you want to see. OK, my one can't light and isn't so smart but this price on the eBay is ultrahigh.

The gadget was made from scrap parts and from very cheap circuit parts. Now go gather materials!

Step 1: Gathering Tools and Materials

• Soldering Iron
• Glue Gun
• Wire Stripper and Cutter
• Electrical Tape

• an old CPU fan
• toroidal inductor
• 2N2222 or 2N3904 or BC547 transistor
• 5v step-up module, (boought on eBay)
• germanioum diodes (5 pieces)
• a small perfboard
• an old phone battery or a 18650 cell
• and a small switch
• bike support element

And that's all. The fan generates AC current that we'll convert to dc current to charge up the battery via a Joule Thief circuit.The Joule Thief gives enough voltage boost for the build in Lithium ion battery. I don't use a charger circuit, because this current isn't enough to damage the battery.

Step 2: AC to DC

First take off the propeller, because we need to find two pins that gives the highest AC voltage. You can see three pins inside the fan. Solder to each one wire then check with a multimeter (in AC mode) that which two gives the best voltage. Remove the third wire that is unusable.

Put back the propeller, and create a diode bridge just like on the images. Connect this to your compter fan. Now the gadget could generate 4 volts and 60mA, that's almost enough for charging the li-ion battery. But using a joule thief we can get a very cool voltage for our battery.

Step 3: Joule Thief

This step is pretty easy. Simply solder together the well-known Joule Thief circuit. If you're done connect it to the DC output of the CPU fan.

On the diagramm the 1.5v single battery means the CPU fan. And the LED means the battery.

Step 4: The Charger Unit

Hook up your battery and connect it to the 5v step-up module. Place between these a power switch. Connect this thing too to the Joule Thief's output. Now the circuit is done and device can be used, but we'll need to make them nicer.

Step 5: Glue!

Get your glue gun and fix everything on the CPU fan's sides.

Step 6: Waterproofig

Using some electrical tape waterproof the system. It isn't the best solution but do his job.

Step 7: Testing

The pictrure qualty is not the best but on the third picture you can see that it works. If works for you too go and put on your bike.

Step 8: Setting Up to the Bike

Get a bike support element and glue oon the top of the device. Now you're done.

Step 9: Have a Good Bike Ride!

If everything works just enjoy the free energy of your bike. I hope you liked and if you want give a vote for me! Thanks for watching :).

Bicycle Contest

Third Prize in the
Bicycle Contest



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    Casting Contest
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    Woodworking Contest
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    Make it Move Contest

We have a be nice policy.
Please be positive and constructive.




Hey, I think is such a great idea! I would to do this project myself. Could you please give me some more information on the model of the 5V step up module? I actually haven't used one of them before so I'm not to sure which one I should buy. Thanks!


can you give me link of 5v step-up module. I need to buy it.

thank you

I'd like to see it adapted to use a window fan mounted on the back rack. Power my TV as I ride. Alright!


I hear all the "professionals" in the comments who are going on about their engineering things and that's fine but dude for a 16 year old this is pretty cool..sounds like a fun project!

1 reply

Can we use this without attaching a mobile bateery
I mean simply using usb port instead of the battery??

1 reply

I would imagine, but without the battery you would probably not be able to keep a charge stored.

My email is could you possibly email me we have a coupke questions including what you used to attach the fan to the bike?

1 reply

I believe he used an old bike bell mount.

approximately how long does it take to charge?

Love the idea! You know what you personally need to advance in, and you do so. Naysayers are just parasites addicted to stagnancy, rather than the naked joy of experimentation! You know, there is a platform that supports those like you and I Tamas. It believes Creators have not been paid their worth near enough over the past centuries, so it allows their fans to do it for them. If you're interested, give me a ring why don't ya? They pay us to tell like-minded individuals like yourself about it. Keep on creating bud!


This was published before Kipkay made his video.

What about motorcycle ? Can we implement same idea on motorcycle

Heyyy we're planning to make this for our scientific investigative project, hmmm can i ask? What's the average speed you must go for it to power up?

1 reply

If there is wind 10km/h is enough.