CORDLESS POWER TOOL SYSTEM

This application relates to a power tool system including a plurality of power tools, a plurality of battery packs and at least one battery pack charger and method for operating the power tools with the battery packs. This application also relates to a method for charging the battery packs and a method for monitoring a state of charge of the battery pack. In one implementation, the system includes an existing battery pack designed to provide (output) a relatively low voltage, an existing power tool designed to operate at the relatively low voltage, a new battery pack designed to provide (output) the relatively low voltage and a relatively high voltage, and a new power tool designed to operate at the relatively high voltage.