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[on:]

Want to set up a Arduino outside for some data logging and thought it would be fun to run it of wind power.

So....I understand using a DC motor as a generator, but how would I take this power and store/dump to say a 12v battery?  

[Reply #1 on:]

Either the generator needs to produce enough voltage to charge the battery, or you need an inverter to step the voltage up. The atmega328 in most Arduinos only needs about 1.8v at lower clock speeds, so why use 12v? I suggest 3NiMH AA cells, which produce 3.6v nominal, a bit more when on charge.

The simplest way to charge them is to connect the DC generator to the battery via a diode. The diode ensures that the battery doesn't drive the generator, only the other way round. I suggest you try a 9v motor. The battery will limit the motor speed and voltage.

One problem with this simple arrangement is that the rate of battery charging will depend greatly on the wind speed. In high winds, the batteries will be over-charged. NiMH cells can stand this to some extent, but it may shorten their life.

An Arduino Uno draws about 45mA, which is quite a lot to drive from wind power using a small DC motor as generator. I suggest you prototype your system on Arduino and then move it to a stripboard design based on the atmega328 chip. Or you can buy a PCB for the atmega328p, without the serial-to-usb chip and other Arduino bits that you don't need. Run your atmega328p at a lower clock speed to reduce power consumption, and consider using the sleep mode when the processor has nothing to do.

[Reply #2 on:]

Use an alternator and a battery. The alternator has a regulator to stop the 12V BATTERY from overcharging

[Reply #3 on:]

Use an alternator and a battery. The alternator has a regulator to stop the 12V BATTERY from overcharging

Without any intelligence in the system you'd have several problems:
1. The excitation coil would drain the battery when the blades were not spinning.
2. The windmill would be difficult to start spinning because the regulator always fully excites the coil.
3. When the regulator cuts off charging it would result in the windmill spinning without resistance and potentially out of control.

To the OP, In general if you're trying to generate power below ~100W you should stick with solar.

[Reply #4 on:]

To the OP, In general if you're trying to generate power below ~100W you should stick with solar.

Solar, if attached to a battery large enough to get you through those long dark winter nights. 

[Reply #5 on:]

Want to set up a Arduino outside for some data logging and thought it would be fun to run it of wind power.

What is the kind of data you want to log?

[Reply #6 on:]

Arduino Fio would be smart option. It works with low power consumption and has connector ready for li-accus. You can hook up Xbee on it for data logging.

http://www.arduino.cc/en/Main/ArduinoBoardFio