Originally Posted by
Road Fan
...
Please explain in detail how the Magnic works. I'm especially curious about the electromagnetics. How can the energy transfer be efficient compared to a hub dynamo when the primary magnetic system, unlike both hubs and bottles is based on a solenoidal geometry and hence has huge leakage fluxes? Air core magnetics are not used for reliable, efficient power systems for this reason - flux linkage is usually quite poor compared to using cores to direct the flux.
I don't know the details any more than you do, and this was my first thought also. But then, why really care? The eddy currents will generate heat and we'll ultimately feel that as a drag, as in magnetic brakes - given that the lights have an acceptable brightness, the drag is the only real issue. I could be wrong but I don't see leakage inductance as looming very large in this application.