Lab testing of battery charge management systems for electric and hybrid electric vehicle battery packs to evaluate cycle life improvement

A project was undertaken to evaluate the benefits of battery charge management systems to control charge and provide equalization to high voltage series-strings of valve regulated lead acid (VRLA) batteries. The goal of the project was to compare the resulting cycle life of charge managed packs to nonmanaged (control) packs. Project results indicated some benefit with use of battery charge management systems and the enormous influence of the charge algorithm applied to the batteries. This paper summarizes the project results, including a description of the test methodology and the battery charge management systems.