Float behavior of VRLA cells: theory vs. reality

Production VRLA cells, made by different manufacturers and designed for a 20 year life, were tested on float. Their actual water consumption rates were measured and compared with target rates based on the amount of water available in the cells. Although the tests are continuing, the data so far suggests that while some cells will achieve their 20 year goal, others may be marginal. Tafel curves and conductivity profiles are presented which show that VRLA cells of the AGM type have characteristics that are extremely variable, even in cells of the same design and batch.