Bike Generator -

Bike Generator

Ever wonder if human energy could turn into energy that can be utilized by electronic devices? Well this Spring the SDSU Green Campus team is showing you how it CAN be done! The team has built a bike generator that can charge your phone, run a fan or even blast your stereo! Keep an eye out for it across campus this semester!

How to Build a Green Campus Bike Generator

****** WARNING *****
This project is DANGEROUS.
Always use caution and protection when dealing with electricity, machinery, and moving parts. This project has the potential of starting a fire, electrocution, dismemberment, severe bodily harm, etc. Consult trained professionals, experts, and engineers. Do not work outside of your comfort zone or base of knowledge. Please use this page as a guide, not as instructions, and always use your best discretion.
The bike generator is really really cool, but not as cool as keeping all of your fingers or just staying alive!
***** ANOTHER WARNING ******
This will be an exercise in trial and error. Prepare yourself.

STAGE ONE - MECHANICAL

Step 1: Find a Bike

We approached our resident halls and found that they had abandoned bikes to donate. The simpler the bike, the better, so long as it has a decent range of gears. ProTip: Suspension systems will take energy out of the system, for comfort get a really big seat.

Step 2: Find a Stand

You will need a stable platform to elevate the rear wheel and to mount the alternator to. An indoor bike trainer will do just that, we got ours from craigslist as they can be pricey. You could also build a stand. Remember though, it will have to be stable, support the bike, and the rider, and mount the alternator.

Step 3: Mount the Alternator

Somehow, someway, mount the alternator so that the pulley is in line with the bikes rear wheel in the stand. It also must turn the correct direction once it is mounted.
ProTip: To tell which way an alternator should spin look at the fan blades. They should blow air into the alternator when it is running.

Step 4: Measure and Belt Up

Measure around the wheel and alternator to see what length of belt you need. You want to size the belt to fit in the alternator pulley, typically a "fractional 3L". Here is a great source for your v-belt.
ProTip: V-Belt names are made up of the size and then the length. So if you were looking for a 3L v-belt 75" long, you would want a 3L750.

STAGE TWO - ELECTRICAL

Step 1: Get Help

Find someone who has experience wiring DC systems. Good resources are electricians, car stereo enthusiasts, and engineering students.
ProTip: Many engineering programs require students to design and build a system for a senior project. Maybe they want to build a bike generator?

Step 2: Run DC

Have an expert run DC into a protected housing and connect to a terminal block (of the right size for your connectors) using appropriately sized wire and connectors. When in doubt, go bigger on the wire gauge and use yellow connectors.
ProTip: Use male/female connectors to make reconfiguration easier.

Step 3: Parallel DC

Have an expert wire the capacitor, DC outlets and inverter in parallel.
ProTip: Capacitors store a lot of energy for a long time and discharge it quickly. They are mean, think of a cattle prod, that can explode if wired wrong. Treat them with respect.

Step 4: Try and Troubleshot

Have an expert seal everything up and go for a spin. If everything doesn't work the first time around, that's ok. Pedal for a little bit to charge the capacitor, make sure the inverter is turned on, and pedal at a good pace until you feel the resistance lighten up.
ProTip: Patience.

STAGE THREE - AESTHETICS

Step 1: Housing

Having nice, clean and organized electrical components is one of the key aspects to the presentation of the bike generator. There are various housing options, but we decided to go with an electrical cabinet which can be found online and a plexiglass cover can be found at your local hardware store.

Step 2: Painting

To accent the clean housing, now is a good time to add some new color to the actual bike. It helps to have friends in the art department who also have access to industrial sanders to get a proper clean start. Spray paint will work just fine, as long as it is administered carefully and as instructed. Remember to only paint in well ventilated areas.

STAGE FOUR - BIKE AWAY!

The donated bike before the makeover

Adding support to the trainer for the alternator is always a good idea.

Housing for all the electronic components

Painting the trainer stand.

School colors. GO AZTECS!

The bike will be a hit with everyone!

For more on home-built bike generators and other DIY information check out instructables