Ok. Folks, first off this is my first post, and I am looking for some answers to some questions I have. I hope someone has the time to answer them :) First off, I'm no expert in physics. I know a billion times more than any of my friends but believe me that is not saying much. I have never really studied it in an academic atmosphere, I have only read several books for laymen, QED, Brief history of time, a couple more hawkings papers, schordingers cat (spelling) and a few others. Just enough to blow my mind. Anyway, I have a long story that I wont bother you guys with that explains how I came up with the idea for a Exercise bike that produces electricity, and then either offers the consumer the option to plug right in to an AC outlet or to store it in a battery. I have some questions that i need answered before I start looking on how to design it. 1. If I were to say use a normal Generator, say like the ones wind turbines use, what kind of current would that produce? AC or DC? 2. A motion specific physics question. http://askalexia.com/2009/02/06/cylec-exercise-bike-generates-electricity-to-charge-your-gadgets/" [Broken] This is the only working prototype that is currently even close to being production value. And I notice the Electrical output is minimal. It takes 2 hours to charge a battery that will power a fan for 3 hours. What would be a system that would maximize the effort used to make the electricity. I was thinking about how a gear system works. Would there be a way to get the bike to were you peddle less and turns the generator faster? 3. What would be the right battery to use. Obviously in America all the power is AC, are standard rechargeable battery's put out AC or DC current? Also any other things I need to look at? I am not familiar with wiring or circuitry so any resources would be great.