So newtus from the previous roll call....watch batteries can be charged through motion but the mechanism is still as big as a watch and doesn't generate much power at all. Normally a watch battery can power a watch for like 2 years without any sort of power so it uses a very low amount, not enough to generate sound...if you ran a radio on a watch battery it would have the duration of an iPod mini at most....that doesn't even have a receiver and it only runs 12 hours max.....so not enough power.