Battery capacity is the size of the battery storage capacity. Battery capacity of the unit is the "mAh", Chinese name is mA (high-capacity battery to measure such as lead batteries, in order to convenience, general use "Ah" to represent the Chinese name is Ah, 1Ah = 1000mAh). If the battery's rated capacity is 1300mAh, if 0.1C (C is battery capacity), or 130mA of current to the battery discharge, then the battery can last 10 hours (1300mAh/130mA = 10h); If the discharge current of 1300mA, that for electric time only 1 hour (actual work time due to the battery's actual capacity of the individual differences and there are some differences.) This is the ideal state analysis, digital equipment, the actual work was not always possible when the current is constant at a value (in digital cameras, for example, because of the work of the current LCD display, flash and other components which occurs on or off the larger change), so the battery can power a device is about the value of the time only, and this value is only through practical experience to estimate. 
 Why use mAh battery capacity as a unit? Because you are certainly buy pre-determined battery voltage, so voltage is determined, the current increases, the stronger the natural Reserve generating capacity, if a parameter used to express the specialized capacity is not necessary. Battery capacity of the unit is mAh (mAH ) instead of mA it! MAh: 1 mAh = 1 mA discharge current, 1 hour, is the power of the unit, rather than the current battery capacity test method: constant current constant voltage to a battery charge, and then to constant current discharge, release How much power is the battery capacity, battery, nickel-metal hydride batteries, but lithium batteries will not do, he has a minimum discharge voltage, discharge voltage that is not less than 2.75V, 3.0V as the lower limit is usually protected voltage. For example, lithium battery capacity is 1000mAh, the charging and discharging current to 1000mA, 4.2V maximum voltage within the battery into the 3.0V, released the battery capacity is the most realistic capacity.