Survey of reliability information on lead acid batteries for commercial, industrial, and utility installations

This paper describes one component out of 239 contributing to the culmination of a 24000 man-hour effort to collect operational and maintenance data. The data collection process and the resultant data on lead acid vented batteries used in uninterruptible power supplies (UPS) equipment is the subject of this paper. In this paper the use of lead acid batteries in UPS is compared to the use of gel cell-stored batteries in them. Gel cell-stored batteries operate in the same manner as a lead acid battery, but a self-contained gel replaces the liquid chemical that is the electrolyte. Information was obtained on a variety of commercial and industrial facility types (including office buildings, hospitals, water treatment facilities, prisons, utilities, manufacturing facilities, school universities and bank computer centers), with varying degrees of maintenance quality. Data collection guidelines and goals were established to ensure that sufficient operational and maintenance data were collected for statistically valid analysis. Time-to-failure data, helpful in model development, were collected, when available, to determine device failure characteristics. A database system, with flexible output capabilities, was developed to track both the equipment information. The results supported the main hypothesis. Maintenance quality level was a predictor of availability. In addition, the information obtained can aid facility designers and engineers in evaluating different designs to minimize production/mission failure and to estimate the down times associated with various systems or subsystems