Picture of How To Build A Bicycle Generator
bike generator 3 (light bulb)-whitebg.png

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.

Parts Tools

- 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.
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Step 1: 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.

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!

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ddemille1 year ago
Can you just use a altenator instead of a motor? Or are they the same thing...
_CrashA_ ddemille7 months ago
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.

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

Is this battery rechargeable ? How does it work exactly ?

GregH5 made it!2 months ago
What size diode do I need?
duckyforbes made it!6 months ago

I made this for my middle school science project. I just twisted the diode around the wire from the motor and held it in place with the clamp of the inverter. Why was the live wire from the motor the black wire and not the red wire? The red wire did nothing, but when I connected the black wire, the motor turned (before I added the diode)


if i understood this right , you need both wires connected to complete a circuit, current flows from negative to positive and without the diode the battery will power the motor as it can leak backwards causing the motor to move in the opposite polarity to the direction you are driving it to create power.

Hello i am doing this same project. Did you do a display board for it? If so can you take a pic of it and send it to my email. My email is javanmsterling@outlook.com.
MuhammadA227 months ago

i want to charge a 12 v 200amp battery with this method it is possible ? and i want to charge it in short time 20 to 25 mints ??? please reply some one ....

dmeyer131 year ago

what if i hook the motor straight up to the chain instead of using a v belt and back rim

_CrashA_ dmeyer137 months ago
Well the ratio would differ that's for sure.
kjdmac7 months ago

Thats Awesome!

but why use a motor? mechanical power from the bike is converted into electrical power, not the other way around

_CrashA_ kjdmac7 months ago
Because a DC motor can work as a generator as well as vice versa. At the end if the day, its just a rotating coil inside a magnetic field - which obviously generates an electrical current.
MuhammadA227 months ago

admin where are you?

MuhammadA227 months ago

admin where are you?

MuhammadA227 months ago

i want to charge a 200amp Battery with 12 volt dc car alternator it gives 30 to 35 amp in normal speed , on extreme speed i think 45 amp? it is possible ? how many minutes required to charge a 200 amp battery?can i charge the Battery with cycle Generator and at the same time can i use the Battery power with an 1000 or 3000 watts inverter/ups

Danp111 months ago

will a DC 12V 50mA 5RPM 31Kg.cm High Torque DC Gear Motor work? It would be great to get specific details about the motor, diode, batery and inverter for those of us unskilled in the electronic arts.

Mojo_JoJo1 year ago

I've been thinking of using a solar cell to charge my inverter
batteries, while I understand the use of the diode, the only problem I
have is how do you stop current being driven into the inverter circuit
by the motor/solar cell?

hnadeem21 year ago

can i use a 12v 7 ampere battery

Ian114871 year ago

you should put this in the green design contest

i made it


johnsv61 year ago

I'm thinking mountain bike for the gears to get a flywheel going. Also, there is a double chain ring (the thingie thats connected to the cranks) Why not run another rear wheel on the front with another chain connected to the second chain ring and be able to turn 2 alternators at the same time?

svdkisore1 year ago

what is the voltage that is poduced during cycling??

do u have a video for the second picture?

how do i make the second one do u have a vide?

dsweid1 year ago
can i by any chance get a bicycle generator to store energy in order to produce electricity to run a builiding??
cyfekt3 years ago
Could you possibly use a larger motor, and 6 batteries??

And if you did what kind of inverter would you need??
depending on wat u like to power up. small fridge, lamp, net work gear. 4000k would do nicely. then yr talking batteries. wat type do u plan to use seald lead acid, universal, or golf cart. golf cart types are the best but expensive. go universal cheaper plus u can get them from harbor freight for roughly 75 bucks or so.
viciousz0rz3 years ago
What is the overall price of a project like this (if I already have a bicycle, anyway)?
from 100 too 200 dollars depending on the route u take.
ExxoShock2 years ago
I was wondering. What affects of a larger than 12V motor on the amount of electricity produced? Because I would like it as efficient as possible, without it being overkill.
go with a geo metro alternator abut 50 bucks +/- at a local auto scrap yard.
Aron3133 years ago
Where did you get the motor?????
correct me if im wrong but it looks like a 24 volt 250 watt electric scooter motor
Is it ok to charge a 12 v battery with a 24v motor?
Sure In fact you need at least 15 volts to efficiently charge a 12 volt battery this is because of the internal resistance. I wouldn't risk going over 30 thou :D
but take care of the current and make sure the current given to battery remains lower than the capacity of the battery if it exceeds the battery will be drained instead of being charged
wagman452 years ago
is it possible to run an inverter straight from the generator without a battery? or do i need one for any excess energy produced? could i just use a capacitor?
yes of course you can ... but the voltage will surely vary on the speed you pedal. if the voltage goes high the inverter will take care but on low voltage nothing can be done..
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