Performance of Ni-Cd batteries after five years of deployments in telecom networks worldwide

As Ni-Cd batteries continue to be deployed in telecom applications worldwide, their operational history is being established. With thousands of strings deployed over rive years, several were chosen as candidates for case studies, to investigate performance in their "as found" condition. The purpose of this paper is to present these results and compare them with expectations. Test sites include field trials, where operational history was measured and recorded, and others sites deployed in a business-as-usual context. Laboratory results are presented and used as a baseline for expected performance when comparing field test data. Some Telcordia test results are also presented. Factors such as battery temperature, operating voltage, and handling of the strings are summarized and compared against recommended practice.