Predicting life of valve regulated batteries, how can we do it right?

The experience with valve regulated batteries have been far from expected concerning life. The batteries found to fail early in these studies have all been tested and evaluated by the manufacturers to have a long life expectancy in the range of 10-20 years. This raises serious doubts about the applicability for accelerated testing techniques used for telecommunications batteries. This paper discusses accelerated testing methods. A presentation of the methodology is made. Results from a study made by our organisation is used to illustrate some of the shortcomings of existing methods. Finally we suggest some improvements in life evaluation techniques.