Which unit is used to express battery capacity?

Which unit is used to express battery capacity?

• A. Amperes
• B. Amp-hours
• C. Volts
• D. Watt-hours

Answer: (B)

Battery capacity is about how much electric charge a battery can store and deliver over time. Amp-hours quantify that charge: it tells you how many amperes you could draw for how long before the battery runs out. For example, a battery rated at 2 Ah can supply 2 A for 1 hour, or 1 A for 2 hours. This makes amp-hours the standard way to express capacity because it directly reflects the total amount of charge available. Volts measure electrical pressure, not how much charge is stored, so they don’t describe capacity. Amperes describe the instantaneous current at a given moment, which varies with load. Watt-hours express energy content (voltage times amp-hours), useful for comparing energy across batteries of different voltages or estimating runtime in energy terms, but when simply stating capacity, amp-hours is the most direct unit.

Battery capacity is about how much electric charge a battery can store and deliver over time. Amp-hours quantify that charge: it tells you how many amperes you could draw for how long before the battery runs out. For example, a battery rated at 2 Ah can supply 2 A for 1 hour, or 1 A for 2 hours. This makes amp-hours the standard way to express capacity because it directly reflects the total amount of charge available.

Volts measure electrical pressure, not how much charge is stored, so they don’t describe capacity. Amperes describe the instantaneous current at a given moment, which varies with load. Watt-hours express energy content (voltage times amp-hours), useful for comparing energy across batteries of different voltages or estimating runtime in energy terms, but when simply stating capacity, amp-hours is the most direct unit.