battery run time
Battery run time is a measure of the continuous run time offered by a fully charged battery (the time it takes for it to run down completely while the computer is continuously operated). Battery run times typically extend to several hours for a notebook PC, and 10+ hours for a hand-held audio player. Attaching an extended battery can dramatically extend a battery's run time.
An electric device's energy consumption varies greatly depending on its environment and manner of use, and strictly speaking battery life varies each time it is used. Therefore it is necessary to understand that the battery life given in a magazine or other advertisement is merely a reference value derived from a posited typical user and manner of use.
Moreover, while the measuring methods are likely to differ from maker to maker, there are several industry standards in effect for notebook PC's that make it possible to compare across makers. Such standards include the "Japan Electronics and Information Technology Industries Association (JEITA) Battery Run Time Measurement Method for Notebook PCs" and "BatteryMark", which is one in a family of benchmarks measuring PC performance that were originally developed by Ziff-Davis Media, the ZDBOp benchmark division (later renamed eTesting Labs), and turned over to the VeriTest division of Lionbridge Technologies in 2002 (www.veritest.com).