Quartz watch battery life depends mainly on two factors: (1) battery capacity, (2) watch movement circuit power consumption. The greater the capacity of the battery, the smaller the power consumption of the circuit, the longer the battery life. The capacity of the watch battery unit with mAh (maH) said, depending on the size of the battery, the general capacity of silver oxide batteries in a few milliamperes to dozens of milliampere hours, the larger the capacity of the more Big. Watt-hour watch power consumption is micro-level, the current IC circuit level can do a microampere or so. In theory, battery life equals battery capacity