A smart battery power balance system and method to maximize the operating life of a mobile computing device and a portable peripheral (e.g., a peripheral having scanning capability). The mobile computing device battery and portable peripheral battery parameters such as battery level, velocity/rate of consumption and usage history are collected. A curve fitting and estimation is done to predict the empty time for complete battery discharge of the mobile computing device and portable peripheral. Based on this analysis, if the calculated empty time of the mobile computing device battery is less than the portable peripheral battery, the portable peripheral charges the mobile computing device battery and if the calculated empty time of the mobile computing device battery is greater than that of the portable peripheral battery, the portable peripheral battery does not charge the mobile computing battery.