There was a great post last year that use a rechargeable 12 volt battery, an otter box and simple electronics attached to a car iPhone charger. A little heavy but a lot of energy and could be trickle charged with solar.
Spidennis.... I believed you posted it. Do you still have link?
Hopefully the beauty in this new forum is that we'll be able to go back and find all that great info that all of us have been finding, I'm sure I got the link somewhere ........
Anyway, all the rage is with the mirage drive but for me it misses on quite a few points and I'm still favored to the typical bike peddle prop idea and with that method I could possible incorporate a hub dynamo?
I'll try and dig up all that past info I had going on but technology is advancing and there's always something new happening.
One cheap idea is to use a walmart D cell to 6 v lantern battery adapter, use 2 and you got 12 volts. I'll try this out sometime as I also want to power an electric bilge pump. I'd not mind the weight if it all tied in together. Are there rechargable D batteries?