A load-leveling (LL) system is needed for the effective use of electric power to preserve the environment in Japan. Although the valve regulated lead-acid (VRLA) battery is considered to be one of the suitable candidates, high requirements of long cycle life such as 2000 cycles or a calendar life of 7 years needed to be solved. We are currently developing a new VRLA battery for this application, and have succeeded in achieving over 2000 cycles with a 35 Ah class VRLA battery. It was confirmed by the detailed investigation after a cycling test of the battery that this cycle performance was achieved by improving the charge acceptance of the negative plate, avoiding the grid corrosion by applying an optimized charge condition. (C) 2003 Published by Elsevier B. V.