Battery Capacity

[technoguy]

The capacity of a battery to store charge is often expressed in ampere hours (1 A·h = 3600 coulombs). If a battery can provide one ampere (1*A) of current (flow) for one hour, it has a capacity of 1*A·h. If it can provide 1*A for 100*hours, its capacity is 100*A·h. The more electrolyte and electrode material in the cell, the greater the capacity of the cell. Thus a tiny AAA cell has much less capacity than a much larger D cell, even if both rely on the same chemical reactions (e.g. alkaline cells), which produce the same terminal voltage. Because of the chemical reactions within the cells, the capacity of a battery depends on the discharge conditions such as the magnitude of the current, the duration of the current, the allowable terminal voltage of the battery, temperature, and other factors.