This page covers the technical details of how to build the energy bikes that we designed and built for the Occupy Wall Street encampment in Zuccotti Park, NYC.
(Note: our direct-contact wheel-to-roller design is not the most efficient for energy output. However, this design was perfect for the needs of Zuccotti Park/Liberty Square after all the outlets had been turned off. We needed to have power 24 hours per day, we could not have people pedaling 24 hours per day, so we needed to use batteries. With two bikes per unit, this system generates the perfect amount of energy to charge batteries. Any more would damage batteries. If your energy bike is going to remain stationary and you are going to use it to direct power appliances or offset the grid, you may want to use more efficient systems with belt drives or generators with bike cogs.)
The two crucial components of the system are the battery boxes and bike stands.
First, The Battery Boxes:
Here are links to all of the parts in our electrical schematic (You can also find many of these parts at your local hardware store): Generator, Diode, Terminal Board, Fuse holder, Fuse, Charge Controller, Watts Up Meter, Battery, DC Outlet, DC Port, Inverter, Box
On the left, you can see that we mounted the terminal, inverter, and watts up meter to the outside of the box. This is so you can easily connect and disconnect bikes from the system, plug directly into the inverter without opening the box, and read the watts up meter to keep an eye on how full the battery is and how much power you are generating.
On the right, you can see that we kept the charge controller, fuses, and most of the wiring on the inside of the box so that it was less likely to be ruined by the elements.
Our Stands were built using a drill press, welder, hand tools, and automotive parts. If you do not have access to a welder, consider this no-weld model from our friends at Occupy Boston
On the left, you can see our motor is attached to a flange. The shaft that comes out of the motor is attached to a coupling, to which we attached a much longer shaft. This shaft passes though two bushing that hold bearings on either side of a roller that is secured to the shaft with set screws. The flange is adjustable to accommodate any wheel size with the large t-screw on the right, which passes through a threaded nut welded to the flange.
On the right, you can see we welded two threaded nuts to the top of our a-frames, into which we screwed bolts, onto which we welded two more nuts to clamp on any size wheel. The bolts easily clamp onto quick release skewers as well as bolt-on hubs, and generally hold well enough that hand-tightening will never slip off.
You can see we taped the diode to the stand, and left plenty of extra wire so the unit can be moved free and easy.