Filled with information about everything from lead acid to lithium polymer, Red Scholefield’s R/C Battery Clinic is a great reference for battery information for R/C and non-rc applications.
Red’s unique knowledge comes from years of working in the battery industry (for GE) and even more years of building and flying models. The one thing to keep in mind is that R/C flyers take their batteries more seriously than almost any other group. Loss of a battery in flight means a loss of control of the airplane which all adds up to a crash. With hundreds to thousands of dollars in the air there’s no room for error on your battery pack.
The concepts Red presents can be applied to other devices. Knowing how to properly charge and use rechargeable batteries will extend their lives considerably and though this site could be organized better there is still a wealth of information here.