Battery capacity, often expressed in Ampere-hours (Ah) or milliampere-hours (mAh), represents the amount of electrical charge a battery can store and deliver. A higher capacity signifies that the battery can provide more current for a longer duration. For instance, a 2000 mAh battery theoretically can supply a current of 2000 mA for one hour, or 1000 mA for two hours, before being fully discharged. However, this is a simplified view, as real-world factors such as discharge rate, temperature, and internal resistance affect the actual usable energy.
Understanding this characteristic is crucial for selecting the appropriate power source for a given application. It ensures the device operates as intended for the desired period. Historically, improvements in battery technology have centered around increasing the amount of energy a cell can store within a smaller size and weight. This progression has significantly impacted the portability and runtime of electronic devices, from mobile phones to electric vehicles. Knowing the amount of charge a battery pack can hold allows for informed decisions regarding efficiency and suitability.