The wind-up battery is simply a multi-purpose version of other wind-up devices which require small amounts of electrical power, such as the wind-up radio. My invention was stimulated by the advent of battery powered wrist-watches that replaced the wind-up variety about a decade ago; I thought, why not reverse the process?! The key idea is that most dry cell batteries are of a standard size and a cylindrical shape, it would be sensible and practical to have spring-loaded wind-up energy storage devices - "wind-up batteries" - of the same size and voltage characteristic; terminals are mounted at top and bottom as with standard batteries as well. In this way, the wind-up device becomes multi-purpose. For larger batteries (like the A-D cells common in flashlghts and the like), a simple spring-driven motor-generator and capacitor sytem should suffice. In order to achieve miniaturization, efficiency or durability, it would be sensible to replace the small motor-generators used in the recently invented (and marketed) wind-up radios with solid-state device, such as torque-sensitive piezoelectric crystals.