IEEE Std 1115-2014 pdf download – IEEE Recommended Practice for Sizing Nickel-Cadmium Batteries for Stationary Applications.
2. Normative references The following referenced documents are indispensable for the application of this document (i.e., they must be understood and used, so each referenced document is cited in text and its relationship to this document is explained). For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments or corrigenda) applies. IEEE Std 1106™, IEEE Recommended Practice for Installation, Maintenance, Testing, and Replacement of Vented Nickel-Cadmium Batteries for Stationary Applications. 1, 2 IEEE Std 1184™-2006, IEEE Guide for Batteries for Uninterruptible Power Supply Systems. 3. Definitions For the purposes of this document, the following terms and definitions apply. The IEEE Standards Dictionary Online should be consulted for terms not defined in this clause. 3 available capacity: The total ampere-hours or watt-hours that can be withdrawn from a cell based upon a specific set of operating conditions (including initial state-of-charge, discharge rate, initial cell temperature, and end voltage) and the state of health of the cell. battery duty cycle: The sequence of loads a battery is expected to supply for specified time periods. float service: Operation of a dc system in which the battery spends the majority of the time on float charge with infrequent discharge. Syn: standby service. period: An interval of time in the battery duty cycle during which the current (or power) is assumed to be constant for purposes of cell sizing calculations. rated capacity: The capacity assigned to a cell by its manufacturer for a given discharge rate, at a specified electrolyte temperature, to a given end-of-discharge voltage. standby service: See: float service. state of charge (SOC): The stored or remaining capacity of a battery expressed as a percentage of its fully charged capacity.
4. Defining loads 4.1 General considerations The duty cycle imposed on the battery by any of the conditions described here will depend on the dc system design and the requirements of the installation. The battery must supply the dc power requirement when the following conditions occur: a) The load on the dc system exceeds the maximum output of the battery charger. b) The output of the battery charger is interrupted. c) The ac power is lost (may result in a greater dc power demand than in item b) above). The most severe of these conditions, in terms of battery load and duration, should be used to determine the battery size for the installation.