How is a battery's capacity measured?

A battery's capacity is measured in amp-hours (Ah), which indicates the total amount of charge a battery can store and deliver over a specified period. This unit provides a clear understanding of how long a battery can power a device before it needs recharging. For example, a battery rated at 1 amp-hour can theoretically supply 1 amp of current for 1 hour, or 2 amps for 30 minutes. This measurement is critical for determining how well a battery can meet the energy demands of various applications, thereby allowing users to select a battery that fits their needs.

The other units mentioned, such as volts (V), represent the electrical potential or force that drives the current. Ohms (Ω) measure resistance in an electrical circuit, while watts (W) quantify power, which is the rate of energy conversion over time. While these measurements are essential in understanding a battery's performance in a circuit, they do not convey its storage capacity directly, which is the core focus when selecting batteries based on their operational lifespan and energy delivery capabilities.