Non-Destructive Testing of Telephone Stationary Batteries

This paper describes a technique for monitoring positive plate growth of normal production lead-acid cells without damaging the cell. The measurement is done in conjunction with a temperature-accelerated aging program. The method is based upon the use of a `reflectoscope', a sonar based instrument which can externally measure the distance between the end of each positive plate and the inside jar wall. The positive plate growth can then be monitored and the rate of growth calculated. A procedure is outlined for calibration of the instrument to this intended use. Typical plate growth measurements are given for commercially available lead-calcium and lead-antimony telephone batteries. The possible application of the reflectoscope in the field and some related problems (for measuring some cells) are discussed.