Have you thought about using Lithium Ion Laptop batteries to replace those NiCads or Lead Acid batteries in your robot? The SRS has published a new article by Don Carveth of Botgoodies that describes how to build a universal Lithium Ion battery charger with Smart Battery interface. The charger is based on an Atmel ATMEGA 8 processor running code compiled with GCC 3.2. The article covers the hardware design, software, construction and operation of the charger. It also provides a lot of generally useful info about the use of Lithium Ion batteries in a robot.