Oxygen reduction cycle VRLA batteries are here to stay

The technology used in Powersafe products is defined in terms of its capability to operate the oxygen reduction cycle, and the related effect of electrolyte saturation, electrolyte density and open circuit voltage are considered. The significance of the relationship between the technology and its recommended float voltage is explained in terms of the open circuit potential, the required over voltage and recharge time. Life temperature issues are considered in terms of initial criteria used in 1982 and the subsequent evolution of acceptable accelerated testing techniques. Operational service lives are reviewed and differences of performance are identified in terms of the cell configuration within a bloc and its type of accommodation. This technology can produce standardised operational lives of between 8 and 15 years. Application management is considered in terms of the relationship between product life and temperature. A method of estimating operational lives from temperature profiles is proposed. Recent developments review improved corrosion resistant grid alloys, improved heat management in systems and some new valve-regulated Pb-acid batteries (VRLA) for higher temperature applications recently introduced into the range.