Explanation: The capacity of a battery is usually expressed in terms of ampere-hours (Ah), which is a unit of electric charge. This represents the amount of electrical energy that can be stored in the battery and is typically used to determine how long a battery will last before needing to be recharged or replaced. Voltage (volts) and current (amperes) are also important factors in determining the capacity of a battery, but they are not typically used as the primary measure of capacity. Weight and watts are also not typically used to express the capacity of a battery.