Fast charge of lead acid batteries at the SCE EV Tech Center

Different types of VRLA technologies from five manufacturers were evaluated and compared for their suitability for fast charging and the effect of successive fast charging on cycle life. Testing was performed on both laboratory bench packs and in vehicle packs. Pulsed current type algorithms were developed in-house and optimized for each battery pack. The packs were life cycled in a partial state of charge (PSOC) mode. It was found that a 70 to 80% charge return could be accomplished, starting from an initial 20% SOC, in a range of 13 to 17 minutes at 3C to 4.6C charge rates. Fast charging of selected lead acid batteries has shown the favorable capability of extending daily EV range without a significant reduction in cycle life.