I was thinking along the lines of a Bicycle wheel with fan blades attached using the large sprocket to drive a small sprocket attached to an alternator to charge the batteries in my Disco, which sometimes sits for 2 weeks without being started.
Something along the lines of Scrapheap Challenge (ABC2 Mon./Sat. 6:30pm), see who can build a workable wind Generator out of whatever is lying around, Regards Frank.