Battery University provides a wealth of information about batteries of all types, in English and in German. Sponsored by Cadex Electronics, the material is based on the book Batteries in a portable World - A handbook by Isidor Buchmann on rechargeable batteries for non-engineers. The site is divided into three parts, on the make-up, charging and storing of batteries; explanations on the different types of batteries; and the people behind Battery University, respectively.
(David Alison's Blog. Photo: Wikipedia) | Cost: Free | For further info...