Here's a solution for pacemakers & other low-draw, implanted medical devices that currently require surgery to replace batteries. Here's how an entry in Wikipedia puts it, "More recently, electronic quartz watches that are powered by arm movement have been developed. A weighted rotor turns a tiny electrical generator, charging a rechargeable battery or capacitor which powers the quartz movement. This automatic quartz arrangement provides the accuracy of quartz without the need to replace the battery or capacitor until it reaches the end of its life, which may be decades." While we're at it, this could be adapted to that expandable vertical rib developed for scoliosis patients.
-- quibix, May 19 2008

US Patent 3,693,625 (1972) http://www.google.c...nts?id=b7YuAAAAEBAJ
Heart Stimulator and Heart-Powered Energy Supply Therfor, by someone French. [jutta, May 19 2008]

Primary cells used in pacemakers typically last about ten years, IIRC. Secondary cells have a limited cycle life, in that their capacity diminishes as they get cycled more and more times. If I had a pacemaker, I'd rather get surgery every ten years than have to worry about whether I'd moved my body around enough recently, and whether I'd need to move my body around more and more often as the cell wore out. Plus, it might last less than ten years before the capacity got too low to be useful (judging by how long phone and laptop batteries last), so surgery might be more frequent, not less.
-- notexactly, May 27 2018



random, halfbakery