# Windmill powered iPod charger

1. Oct 14, 2013

### LightningB0LT

I'm a high school physics student, so keep my limited knowledge in mind. Basically the other day I had the idea to create a charger for my iPod that's powered by a windmill, which I could attach to the outside of my car. I've never actually built a windmill before, but I'm pretty confident I can get one working. What I don't know, however, is whether I can charge my battery with the AC current the windmill will produce. Can you charge a battery with AC, or does it have to be DC? I'm sure there's also other potential problems that I haven't thought of, but I thought it was a cool idea so I decided to look into it. Is something like this even possible?

2. Oct 14, 2013

### Aero51

You would need an AC to DC converter first. I do not know if they make them at the small AC power levels you will be generated. You are going to need (12V DC at 1A according to the apple website). One problem I can think of is maintaining a constant frequency of the voltage going into the AC-DC converter. For example, if you drive real fast you will probably get greater than 60hz of electricity, but if you travel, say at 20 mph, you may only achieve 20hz.

I am not an electrical engineer so I cant give you 100% full-proof advice.

3. Oct 15, 2013

### SteamKing

Staff Emeritus
4. Oct 15, 2013

### LightningB0LT

Without knowing exactly what voltage I'm going to generate yet, do they make AC/DC converters that would potentially work? And yeah, I wondered about the varying current too. Is there something l could buy to somehow regulate that?

And no, my car's a 93 so it doesn't have cigarette lighters. Otherwise that would have been my first solution lol

5. Oct 15, 2013

### SteamKing

Staff Emeritus
My car's a 97 and I got a lighter.

6. Oct 15, 2013

### Aero51

You cant answer your question without addressing the issue of voltage output. You may be able to generate DC current directly using a small hobby shop motor (with very little internal friction and magnetic resistance) and a very light propeller. You will not get many rpms unless you use a pinwheel like configuration.

7. Oct 19, 2013

### peterBC

I have had cars from 1963 to 2006 and they have all had cigarette lighter sockets.
It is fairly easy to add, they are sold in auto parts stores.

You should connect the cigarette lighter (12v socket) to the fusebox or if you connect directly to the battery use an inline fuse of 5 or 10 amps (or less) so you do not cause problems.

If you are generating power with a windmill when driving your car, the energy produced will be far less than the extra gas used because of wind resistance and losses. You might also have trouble attaching it securely so it will stay attached at highway speeds. using the car's electrical system and a ready made car charge cord is a better choice IMO.

I think the charging circuit is fairly simple with a voltage regulator and probably a capacitor or battery to smooth the power. but I would not trust it to charge a valuable thing like an ipod without damaging it.

8. Oct 19, 2013

### peterBC

an ac to dc converter is just a rectifier which can be 4 diodes arranged in a diamond shape for a full wave rectifier. You can also buy a rectifier which does it for you with 4 legs. While I do not think using a windmill on your car is an especially easy or inexpensive way to charge your ipod, it is good that you are thinking about it and learning about circuits and electricity