Battery capacity is the stored electrical energy in a battery. It is a major characteristic of batteries which cannot be predetermined with certainty, because there is variation between cells and tests of this variable are destructive. However, battery capacity can be estimated from tests of samples. In the case of small lot quantities of expensive batteries, the capacities of batteries and battery packs can be estimated from test results of sample battery cells. Conversely, battery or battery pack capacity requirements can be translated into specifications for tests of sample cells. Capacity test specifications are discussed and developed from the consumer's point of view.