APPLICABILITY OF ACCELERATED TESTING CONDITIONS ON LEAD-ACID BATTERIES FOR PV SYSTEMS ― RESULTS FROM CYCLING AND DEEP-DISCHARGE LABORATORY EVALUATION

摘要

This paper reports on the applicability of accelerated lifetime procedures on solar type lead-acid batteries. Two different testing procedures were examined, namely "cycling" test and "deep discharge" test. The "cycling" test simulated battery-shedding phenomena, while the "deep discharge" test provoked rapid battery sulphation and examined the recovery capability of a battery. Seven lead-acid battery types were tested from five different manufacturers. The results showed that flooded batteries lasted approximately 500 cycles under the accelerated conditions of the "cycling" test. The equivalent cycling ability was calculated more than 1300 cycles under normal operating conditions taking into account that during its lifetime the battery's capacity does not fall below 80% of the nominal. With VRLA batteries, the final results indicated that under accelerated conditions, cycling capability was between 265 and 305 cycles for three different battery types. This corresponds to an average of 1100 cycles at room temperature. These results are satisfactory in terms of battery performance and also, in terms of validation of the applicability of the accelerated cycling procedure as a standard test in laboratories for the assessment of the lifetime of lead-acid batteries.