I am trying to find this out myself.... what can be generated with various coils/configurations. I tried this with my faster wheel ( 8 ceramics spinning at 2500 RPM ) I could get it to generate with the coils but it seemed not to be as effective as with my 300 RPM Neo set. ( mind you the 300 RPM is turning a wind generator which is now up to 5.5 V ) But the thing that got me was it did not slow down the speed of the turnning of the wheel. I could easily hook up 12 of these around the wheel and get 7V * 12 with out slowing down the wheel and I am sure charging the batteries at the same rate. As I said, I can't wait till my larger sphere neos get here. :-)

I am hoping the fine magnet wire is not a factor.... and i can use my 20 gauge wire.