The DS2781 measures voltage, temperature, and current, and estimates available capacity for rechargeable Lithium-Ion and Lithium-Ion Polymer batteries. Cell stack characteristics and application parameters used in the calculations are stored in onchip EEPROM. The available capacity registers report a conservative estimate of the amount of charge that can be removed given the current temperature, discharge rate, stored charge and application parameters. Capacity estimation is reported in milliamp hours remaining and percentage of full.