COMPARISON OF SERVICE TEST-RESULTS WITH ANALYTICAL PREDICTIONS FOR A LEAD-ACID-BATTERY

IEEE Standard 485 [1] recommends methods to adequately size lead acid storage batteries for generating station or substation use. However, it is often necessary to evaluate changes in the battery duty cycle because of proposed load additions, load changes, or changes in the operating times of loads. The ability to reasonably predict battery terminal voltage for a given duty cycle is a useful tool for performing voltage drop calculations and predicting battery performance. An analytical method for predicting battery terminal voltage versus time for a given duty cycle has been used for years in the industry. This paper reviews the analytical method, including considerations for battery aging, temperature correction, and adjustments to manufacturer supplied data, and presents the results of Service Tests as compared to predicted battery terminal voltages for an eight year period.