Float life verification of a VRLA battery utilizing a high purity electrochemical system

Claims made at INTELEC battery workshops suggest that VRLA batteries may have a reliable life limited to as little as 2 years in standby applications. Furthermore, several published papers propose that one of the inherent failure modes is loss of capacity of the negative electrode. This paper examines float life verification of commercially available high purity VRLA batteries in light of this concern regarding negative electrode capacity loss and includes data from real-time room temperature float testing which has been ongoing well in excess of 10 years. The condition of the negative electrode, from both new and real-time aged product, has been carefully examined by both electrochemical measurements of the product and also by analyzing the morphology and crystallography of the plates. The condition of the positive grid has also been examined to determine the extent of corrosion. In conclusion, this paper demonstrates that by using a high purity VRLA technology, which has been commercially available for 25 years, it is possible to far exceed 2 years of reliable service. Properly designed batteries using this technology have been proven to deliver greater than 13 years in real-time float service