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How are volts, amperes, and watt-hours used to describe a battery?
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battery
Cutaway view of an alkaline–manganese dioxide power cell.
Batteries are described using several key electrical units that define their potential, current capacity, and total energy output:
- Volts (V): This unit measures electrical potential or electromotive force. It indicates the difference in potential between a battery's terminals, which drives the flow of current through a circuit. A battery's total voltage is determined by its internal chemical reactions; for example, multiple cells can be connected in series to increase the total voltage.123
- Amperes (A): The ampere measures the rate of electric current flow. In a battery, the current is generated by chemical reactions at the electrodes. The amount of current a battery can deliver is limited by the diffusion rates of its internal chemicals and the surface area of its electrodes.32
- Watt-hours (Wh): This unit represents the total energy capacity of a battery. It is calculated by multiplying the current (in amperes) by the time of discharge and the average voltage. Essentially, it quantifies the total work a battery can perform over a specific period.3