So you want to make yourself an electric generator? Well that's great. In a few easy steps, you can make an electric generator to charge a battery and power anything you need. They are great for power on the go, such as camping, hiking, or picnics!
The first thing to do is find a DC Motor. Any size will work, but you'll need to match your battery to the voltage of your motor. A 12 volt DC Motor is a common size, and will be good for home applications of an electric generator.
Make a crank for the shaft of the motor. This can be done a few different ways. One of the easiest is to use a piece of metal or plastic bar stock, and drill a hole that fits snugly over the shaft of your motor. Consider putting a spinning handle on the crank to make it more comfortable to turn. You can model yours after the cranks seen on wind up flashlights and radios.
Find a rechargeable battery of comparable voltage to your motor. For a 12 volt DC Motor, use a 12 volt battery. I like to use Sealed Lead Acid (SLA) batteries, since they can be recharged many times, are relatively inexpensive, and can be turned upside without spilling the battery acid (unlike car batteries).
Connect the DC Motor's anode and cathode (the prongs at the rear of the motor) to the battery, being sure to match the proper positive and negative. If you aren't sure which is positive and negative, use a volt meter to test. Use wiring that is suitable for the amount of voltage and current the motor is rated for. If you aren't sure, stop by an electronics store such as radio shack, they can help you choose the appropriate sized wiring.
Turn your crank on the motor and you will begin generating electricity. Connect a device capable of running on 12 volts (or an inverter for 115 volts) to your battery and you will now be powering your device!
Plan out your build before you start. This will help you eliminate waste and mistakes
Be careful when using power tools Use proper safety equipment when using tools, such as gloves and safety goggles