Powersafe valve regulated cells and batteries-a review of operational performance with design life predictions

The Powersafe produce, launched in October 1982, was the first sealed lead-acid recombination product (of a large capacity) to be developed for use in telecommunication power systems. The authors indicate that performance data on prototype products, can, when tested in sufficient quantities and presented as a population distribution plot, indicate the viability of a product. Performances based on the arithmetic mean value or the mode value of unit test data are overstated compared to the performance of a battery of units. The claimed battery performance for Powersafe is based on the arithmetic mean of cell performances minus three standard deviations. From initial capacities and service life capacities obtained from field tests, the authors project that the Powersafe product should have a design life of 10 years