Introduction: How to Build a Bicycle Generator

Picture of How to Build a Bicycle Generator

The intention of this project is to build a straight forward human powered generator from a used bicycle and to use it to power light bulbs, blenders, cell phones, laptops, and other small appliances. This project will help one develop engineering skills while learning about a clean way of generating electricity.

The project was created as part of Infrastructure Academy's environmental technology curriculum for high school students, so it is intended to be both achievable and affordable.

Before continuing with the actual bicycle generator, one should understand how it works, and the components that make it up. View the PowerPoint presentation before moving on to the next step.


- 2" X 4" Wood
- Wrench
- V-belt
- Saw
- Diode
- Wood screws or nails
- Battery
- Hammer or Screwdriver
- Inverter
- Tape Measure
- Wire
- Screwdriver
- Motor (12-V or higher)
- Perforated plumbers steel
(if motor does not have mounting bracket)

Note: The bicycle generator could be accomplished by skipping steps 5, 6, 7, and 8, to save money, but connecting anything other than a halogen lamp directly to the motor is not recommended due to the varying voltages.

Step 1: PowerPoint Presentation

Picture of PowerPoint Presentation

Step 2: Obtain a Bicycle and Remove the Back Tire.

Picture of Obtain a Bicycle and Remove the Back Tire.

You will need to unscrew the back rim to remove the tire and tube. Since the only part of the bicycle that needs to work is the chain and pedals, a junk bike or an old used bike would work just fine.

Step 3: Build a Stand to Elevate the Bicycle Off the Ground.

Picture of Build a Stand to Elevate the Bicycle Off the Ground.

The design of the stand is completely up to you. A few examples are shown below. Just be sure that the stand keeps the bike elevated and secure. If your bike has pegs attached to it, make sure your stand accommodates that feature.

The stand should be built so that the rear wheel of the bike is about 5-7 inches off the ground. The dimensions of your stand will be specific to your bike.

Before beginning construction of the stand, be sure to draft a design with appropriate dimensions. A design on paper will save time and prevent mistakes.

Step 4: Attach the Drive Belt Along the Back Rim.

Picture of Attach the Drive Belt Along the Back Rim.

A drive belt can be purchased at any auto parts store. You will need to remove the back rim to attach it. Make sure to measure the distance from the motor to the rim so you obtain the appropriate size.

Step 5: Attach the Motor to the Stand.

Picture of Attach the Motor to the Stand.

A 12-volt DC motor or higher is recommended. The wattage of the motor depends on what you want to power. The motor should be securely mounted to the stand. Mount the motor at a distance that will tightly secure the drive belt on the motor shaft. The belt and motor shaft should spin concurrently – make sure there is no slipping between them.

Step 6: Place a Diode in Series With the Motor and Battery.

Picture of Place a Diode in Series With the Motor and Battery.

Make sure the diode is only allowing current to flow from the motor to the battery. The cathode should be pointing towards the positive terminal of the battery.

Step 7: Connect Battery to the Diode.

Picture of Connect Battery to the Diode.

The battery should be connected in series with the motor and diode. The negative lead form the motor should attach to the negative terminal of the battery. The positive lead from the motor should be attached to the diode, and the diode to the positive terminal of the battery.

Step 8: Connect the Battery Leads to the Inverter.

Picture of Connect the Battery Leads to the Inverter.

You could use an adapter to connect the battery to the inverter, or you will need to solder or tape the battery’s leads to the inverter so the circuit is secure. Be sure to correctly connect the positive and negative terminals of the battery to the inverter or you will blow the fuse in the inverter.

Step 9: Plug the Appliance of Your Choice Into the Inverter.

Picture of Plug the Appliance of Your Choice Into the Inverter.

Once the motor is secured to the belt, you will need to use a multimeter to measure how much voltage is being exerted while you pedal. Depending on how much you exert, you will be able to power small appliances. With the knowledge you’ve gained, try to make changes that will make your generator better and more efficient.

Fun Ideas
Here are just a few suggestions to what you can do using your new bicycle generator.

Charge your phone and exercise: Ever charged your phone and just waited until it was done charging? Why not get a workout and charge it at the same time! See how much time it takes to charge your phone. Try to set a time and try to beat it in the future.

Human-Powered Smoothie: Think you can make a smoothie without wasting energy in your home? See if you can generate enough energy in your bicycle generator to run a blender. Then, see if the blender has enough power to make a smoothie.

Eco-Breakfast: If you are the type of person who wakes up in the morning wanting to exercise, then try this. Use the bicycle generator to make some waffles and toast. There’s nothing like building up an appetite, exercising, and cooking at the same time.

Think about some more fun ideas you can execute using the generator and test them out!


VasV (author)2016-05-29

I was actually hoping this would have been, or included instructions, on how to make the bike produce power while you're outside doing stuff, not just a stand still bike. I want to be mobile while I power a battery on the bike. My goal was to replace the back tire with a motored tire, and charge the battery that powers this motor while I ride, and turn the motor on when I need to go up a big hill or need a break in peddling for a bit.

JoshD164 (author)VasV2017-12-14

Look into hammacher schmlemmer.. they have 2 different styles with a chain 1500$ and with out 3800$ chainless your pedals are cranking an alternator and harvesting power off each tires natural movement.... I know you don't want to spend that, but maybe between this article and brain power you could "reverse" engineer something

Theelvenarcher (author)VasV2017-01-25

so you clicked on this even though you wanted something completely different.

adriansebastiani (author)VasV2016-06-22

JoshD164 (author)2017-12-14

Is there anyway this could be adapted with an actual power bank like that of a solar power generator? I want to build this in hopes to power a 32ft pull behind trailer

IsaacSTEM (author)2017-11-28

Is there any alternate motors I can use such as a Fan Motor?

CloudS7 (author)2017-11-06

Hi Masters? Can i light a bulb using the generator but the mechanical force is much smaller?

IsaacSTEM (author)2017-11-02

I feel like you should do a nice cover so that way it looks nice and fits with your type of house design

IsaacSTEM (author)2017-11-02

Can this charge a laptop or Eye pad? Can i make one without the wheel?

jeevankumark (author)2017-05-10

total cost

2021W (author)2017-05-04

Hi, I'm trying to make this for a school project and I had some questions.

Where can I get the supplies?

How much energy does this produce?

Is there a way to increase the amount of energy produced?

Is there a certain length I would need for the belt?

Thanks for the help, and if you have any recommendations I would love to hear them.

EduardD8 (author)2017-04-19

Hi! Can you help me with the belt? Which belt did you use? It is not visible from the photo. I have a problem to choose a belt on the chain sprocket :/ I have the same motor and the same sprocket as you do. Thanks a lot!

Please write me also to

YashB59 (author)2017-02-21

sir how much power will it make.( ampere,volts,watt)

dumpstar (author)2017-02-19

I attached a PM DC treadmill motor directly to this 250w Grid Tie Power Inverter:

And it plugs directly into my wall and brings down my electric bill.

MikaM2 (author)2017-02-02

IMHO. From inverter there will be big losses of energy. It is better to use 12V battery and to connect the laptop via car devices.

smart maran (author)2017-01-03

why we using diode in the battery??

spadoosh (author)smart maran2017-01-11

A diode allows the current to flow in one direction. It stops the battery providing power to the motor.

BayBuilder (author)2016-10-25

Charging a battery at 30A requires an input power of 12Vx30 = 360 watts. You may be able to pedal that hard for a short while, but not long enough to fully charge a large battery. Doing a quick Google search: Olympic cyclists peak at about 1,200 watts during a 5-8 second sprint and can sustain 400 watts for about an hour.

Using a 1,000W inverter would drain your 200Ah battery in less than 2.5 hours, not 50. (100W/12V = 83A, 200AHr/83A = 2.4 hours) Actual running time will be considerably less due to battery inefficiency at high discharge rates.

Dick_Knipple (author)BayBuilder2016-10-26

oops :-)

Dick_Knipple (author)2016-10-26

removed because of error.

See comment below...

martinbeaulne (author)2016-09-02

Please, before trying to build this, be sure your motor uses permanent magnets; otherwise it will not generate electricity.

Few motors, these days, use magnets. I'm very surprised no one talked about that.

Mr_knownothing (author)2016-01-22

Can I use a stepper motor for this project?


JamieF32 (author)Mr_knownothing2016-08-28

Probably not, as a stepper motor has wierd wiring (not -ve and +ve)

forgivableirwin (author)2016-08-21

How much would the materials cost? Thank You!

AbdullahK45 made it! (author)2016-07-09


I have gotten all the parts ready to build this the only problem is that I cant get the motor to spin as the connection is too lose. How did you manage to get it to rotate like that? This is the v belt and motor I used. Many thanks.

GroceryO (author)2016-04-07

What will the Independent, dependent and controlled/fixed variable be for this experiment?

YasserK3 (author)2015-11-20

I could not find the right motor or generator to use .. Can someone plz attach me a pic of the right one ,,, and what kind of belt I should use

Dick_Knipple (author)YasserK32016-03-25

Try a car alternator

chidvilash (author)2016-02-05

am doing on this project...
can i know ,how much distance to be kept between the cycle and dynamo in order to get max power? is this distance effect the power generation?
can we add any extra equipment ,in order to look project differ from simple

DearH (author)chidvilash2016-03-25

I dont think distance actually matter but you can add a couple of gears in shaft which connects your dynamo with belt or add a shaft, use gear ratio gear 1 teeth/gear 2 teeth make sure first gear has more teeth than second one for more speed and effciency.

JohnnyW16 (author)2016-03-20

What is the point of the car battery? And What are those blue and red wires called?

Tirtharajking (author)2016-01-29

Can i use fan's motor to generate elcricity???/

KyleM80 (author)Tirtharajking2016-02-28

Granted, while there are other factors that play into it (such as how MUCH electricity you can generate), yes you should be able to.

notoriouslev made it! (author)2016-02-14

So I came up with a way to guesstimate the v-belt length you'll need to order for this project. It's pretty simple and should work with any sized bike. A quick note. You may want a bit more room for your generator, but mine is small enough that it fits nicely at the outer edges of the rim (see pic)

Step 1: Measure the size of your bike's rear wheel. Mine (from rim to rim - not including the tire was 26" tall, which means I have a radius of 13". The equation to get the circumference of the rim is 2 x pie x radius = 2 x 3.14 x 13 = 81.64" around.

Step 2: Subtract 1/4 of the circumference: 81.64 * 75% = 61.23

Step 3: Add the diameter: 61.23 + 26 = 87.23" Long


Optional Step 4: You can add extra length to the v belt in case you don't want the generator sitting just below the rear wheel's exterior. For instance to place the generator 1 foot behind the rear wheel, you add 12" for the extra distance behind the wheel, and then you use the Pythagorean theorem to get the additional v belt required to reach back to the tire: (12 x 12) + (13 x 13) ...then get the square root = 17.7". So to place the generator 1 ft behind the rear wheel of this bike, we add 29.7 inches to the 87.23" we already had and get 116.93"

chidvilash (author)2016-02-05

am doing on this project...
can i know ,how much distance to be kept between the cycle and dynamo in order to get max power? is this distance effect the power generation?
can we add any extra equipment ,in order to look project differ from simple

YasserK3 (author)2015-11-20

I'm working on A Bicycle Generator project . I need some help with the calculation like the equations for calculating Ratio and speed ,,,, plz if u can help me with the calculation here is my email.


Mariaalejandraescalante (author)2015-11-16

If I use a 12 v motor, 24 v battery. Which inverter do I need, and which diode?


HarshitK4 (author)2015-11-16

can any one give synopsis onthis

mohameda186 (author)2015-10-23

what is the out put power of this setup ?

AlexM154 (author)mohameda1862015-11-15

Power will be limited by your electrical generator, or your pedaling ability, whichever is smaller. Note, average long-time (e.g. an hour exercise) human pedaling ability is about 100-200W.

AdityaP32 (author)mohameda1862015-10-27

Exactly the same Question I also need to know ..... ??

krishnakk (author)AdityaP322015-11-14

it depends how much current and voltage u are able to draw from motor.

akosikulot (author)2015-11-13

what about the diode, what kind of diode to use? any specific resistance or wattage?

krishnakk (author)akosikulot2015-11-14

u can use diode amp. producing. diode having least voltage drop . may be schottky diode

krishnakk (author)2015-11-14

can i use washing machine motor (220v, 50Hz, 1 phase, 4 poles)

ddemille (author)2014-01-08

Can you just use a altenator instead of a motor? Or are they the same thing...

_CrashA_ (author)ddemille2014-12-23

No they are not the same thing. An alternator is an AC generator which requires electricity to excite the rotors magnetic field (since there are no magnets in an alternator). When the voltage gets to about 12v+ it will disconnect the battery since it would have "self excited" the rotor by the electricity it is generating itself. The problem is, is that the alternator needs to be spinning at an a solute minimum of about 800RPM+ to start self exciting. You need to spin the rotor at about 1000-3000RPM depending on the alternators specifications in order to generate the amount of power its rated at / you want to generate.

brightout27 (author)_CrashA_2015-07-01

Does that mean a sufficient energy is still generated if the dc motor will be run up to 100 RPM? Thanks!

souheib.sfaxi (author)2015-06-16

Is this battery rechargeable ? How does it work exactly ?

GregH5 made it! (author)2015-05-13

What size diode do I need?

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