Introduction: BikeGen

About: I enjoy building things more than actually using the things I build

BikeGen is a small power generator, mounted to a bike, that recharges two AA batteries while you ride. The batteries can then be used to power the lights on you bike or you can take them out and use them in your other electronic devices. BikeGen also has a standard car 12v power outlet that could be used to recharge your Ipod or cell phone.

This is an updated version of my original Bike Generator. The first version served its purpose but was fairly limited. BikeGen, is better in almost every way and here are some of the reasons why:

1. The generator motor is now mounted with more rigidity to the rack instead of the frame.

2. The friction drive wheel is mounted to the motor with a clamping coupler and now runs on the braking surface of the wheel and not directly on the tire.

3. BikeGen recharges two AA batteries instead of powering the headlight directly, so the lights stay on even while your stopped.

4. Two AA batteries are used to power both the head light and the tail light, which means I don't have to bother buying AAA batteries for the tail light.

NOTE:Please read my Bike Generator Instructable and follow the steps about building the the circuit board before attempting to build BikeGen.

Step 1: Get the Tools

Step 2: Get the Materials

Here is all the materials I used to build BikeGen.

Raw Materials
Aluminum Angle 3/4"x3/4"-1/16"thick
Aluminum Angle 1-1/4"x1-1/4"-1/16"thick
#6-32 All-thread

4 - #6-32 nylon-lock Nuts
2 - #6-32 x 1-1/2" long Machine Srews
2 - Springs
2 - 1/2" #4-40 Stand-offs
4- #4-40 x 1/4"long Machine Screws
2- #4-40 Nuts

Electrical Parts
18 gauge wire - roughly 25ft
2 - DPDT switches
12volt car outlet
2200 ohm resistor
Battery Holder for 2 AA batteries
D-Sub connectors
Everything used to make the Bike Generator

Other Needed Items
Small Plastic Organizer Box

Step 3: Make the Generator Motor Mount

The motor mount is spring loaded and the friction wheel rides on the braking surface of the rim. This works much better than my original Bike Generator which tended to bounce around on the tire while riding. I also got different tires which wouldn't work well that set up because the have tread vs. the smooth tires I had.

The 3/4" aluminum angle was made to mount to the motor The 1-1/4" aluminum was made to mount to the rack. These two parts are connected together by the two #6-32 machine screws and the two spring. The screws thread into the tapped holes on the motor mount with the springs around them. This allows for the motor to move with the rim as you ride. This ensures that the generator wheel is always in contact with rim. The #6-32 all-thread was used to make two U-bolts. They fit the size of the bars on the rack.

I have included two drawings in the pdf for the two brackets I made to mount the motor. I also created an assembly drawing of the motor, wheel, and brackets. You will need to download the freeeDrawings Viewer to view the drawing.

Step 4: Wire the Electronics

All of the electronics of my Bike Generator were reused and I added the AA battery car charger. The circuit from Bike Generator needs to be changed slightly though. For instructions on how I put together the circuit refer to Bike Generator. For BikeGen I wanted to be able to recharge batteries while I rode and then use those batteries to power both the headlight and tail light. I wanted a good charge controller as well so that the batteries would not be over charged. I looked at a few charge controller kits that you solder together be decided to hack something instead. So I found thisAA Car Charger on ebay and was able to get it shipped for less than $7. This charger has a 1amp charge rate and can charge two AA's in two hours in a car. It also has a trickle charge feature that maintains full battery charge. This is perfect for what I wanted. Also because I was going to output 12volts I got a car power outlet so that I could recharge my cell phone as well.

The variable voltage regulator needs to be set up to output roughly 12 volts. Here is all the information you'll need on the voltage regulator LM317 Voltage Calculator I chose to shoot for 13.75volts, because I have measured the power outlet in my car and its usually over 12 volts. Also I could reuse the 220ohm resistor for 13.75volts. The original 220ohm resistor needs to be desoldered and then placed in the same location as the 150ohm resistor. The 2200ohm resistor can then be soldered in the place of the 220ohm resistor. I then used a dremel to spin the motor to make sure the regulator was working right. It output 13.88volts which was right on the money.

So the original Bike Generator circuit will rectify the AC power from the motor and regulate the voltage to 13.75volts. That power will then be fed to the charger circuit. The charger is then connected to a DPDT switch which is used to switch the batteries form the charger to the lights.

Step 5: Mount Everything to Your Bike

The motor mount should be easy to mount, but I haven't figured out the best way to mount the electronics yet so for right now their just duct taped to the handle bars. The lights will also have to be modified so that you can connect them to the batteries in the electronics box. For the tail light I soldered wires to the PC board and drilled two small holes to run the wires through. In the head light I just wedged the wires onto the connectors for the bulb and put a drop of hot glue there to hold them in place. For both lights I used a D-sub connector on a short section of wire, this is so that I can disconnect the lights easily. I ran wire from the electrical box to each light with pins soldered to the ends. I twisted two wires together with a drill for each light.

Once everything is connected mount it all to your bike and your ready to go.

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