10. REPLACEMENT STORAGE BATTERY SIZING

Sizing of a storage battery is generally based on three kinds of loads: 

1. Power circuit breaker or circuit switcher tripping. This load is normally of short duration and uses few ampere hours. When replacing a station battery, the battery must have ample ampacity to handle this short term load. 

2. Normal battery loads that turn on automatically with loss of station power must be calculated by multiplying load amperes times expected duration and a rating factor. Typically, this rating factor would be 1, based on a 3­ hour discharge rate. 

3. Loads remaining after personnel have manually deleted all possible loads. This battery load would normally be based on an 8-hour discharge rate with a rating factor of 1. 

The ampere-hour rating combining loads No. 2 and 3 normally is used to size a station battery provided the short term ampacity is sufficient to handle the load of No. 1. 

Computer software is available from battery manufacturers at no cost to simplify the sizing of different type batteries using IEEE methods. 

11. STANDARDS 

Additional information on batteries can be obtained from battery suppliers and from IEEE standards as follows: 

IEEE 485-1983—Recommended Practice for Sizing Large Lead Storage Batteries for Generating Stations and Substations 

**IEEE 450-1995—Recommended Practice for Maintenance, Testing, and Replacement of Vented Lead-Acid Batteries for Stationary Applications 

IEEE 1184-1994—Guide for Selection and Sizing of Batteries for Uninterruptable Power Supply (UPS) 

IEEE 1115-1992—Recommended Practice for Sizing Nickel-Cadmium Batteries for Stationary Applications 

*IEEE 1106-1995—Recommended Practice for Maintenance, Testing, and Replacement of Nickel-Cadmium Batteries for Stationary Applications 

IEEE 1189-1996—Guide for Selection of Valve Regulated Lead-Acid Batteries (VRLA) for Stationary Applications 

*IEEE 1188-1996—Recommended Practice for Maintenance, Testing, and Replacement of 

Valve Regulated Lead-Acid (VRLA) Batteries for Stationary Applications

 * These IEEE Standards are referenced extensively in this FIST.