Battery capacity is a term used to indicate how much energy is stored within a battery. The unit used for this purpose is known as watt-hours or the symbol Wh. A watt-hour is the amount of voltage that is provided by the battery provided by the amount of current (Amps) that the battery is able to provide in a specific amount of time. Generally, battery capacity is indicated in denominations of one hour each to simplicity. For example, a single 1 Ah battery is capable of providing a maximum of 1 Amp of current for an entire hour.

Battery Capacity and Power Capability

One thing that many tend to forget is that the actual amount of power drawn from a battery is usually limited. Which means that a 1 Ah battery will not offer 1 Amp of current every hour? The actual output level is usually significantly lower too prevent a battery from overexerting itself. The actual amount of power drawn is what we call power capability.

Power capability is normally measured in C’s. Battery manufacturers divide the amp-hour capacity by one hour to calculate C. A 2Ah battery’s C is 2A. It is essentially the amount of current that a battery allows to be drawn without exerting itself. The higher the power capability of a battery is, the more current it can supply to appliances.

Lithium-Ion cells usually have low power capability, but they are designed specifically for appliances that are meant to be used for extended periods of time. Li-On batteries with low power capability and high durability are included in commonly used appliances and electronics, electronic cars and for industrial uses.