A method and apparatus for charging a battery with a finger actuated low mass spinner electromagnetically converts the mechanical spinning energy to the desired battery charging voltage. The charger may be a self-contained portable battery charger unit for use with any of multiple devices containing respective batteries, or it may be a permanent part of such a device. The spinner may be a modified fidget spinner to which a shaft or axle is fixedly attached to rotate about that axis with the spinner and has one or more permanent magnets secured for rotation therewith. Alternatively the spinner may be more like the fidget spinner, without an axle rotating therewith, and having magnets on its rotating arms. In either case, the magnetic fields of the rotating magnets induce voltage in one or more induction coils to generate a battery charging voltage.