The Capacity Of Laptop Batteries Explained Laptop batteries are rated by, Voltage (V) and Milliamp-hours (mAh). Voltage
is the rate at which energy is drawn from the battery and Milliamp-hours Represents the capacity of the battery. The Milliamp-hour rating Corresponds to the run time of the battery. A battery with a high Milliamp-hour rating has a relatively longer run time than a battery with a Low Milliamp-hour rating.