Panasonic Storage Battery Co., Ltd. developed a flooded type lead acid battery at a low cost, which is suited to an idling stop system aim to improve fuel economy. When compared with conventional vehicles, a deep discharge and charge cycle is repeated in the battery of the system, resulting in a severe damage to the life. Accordingly, excellent cycle life characteristics, when compared with a conventional battery, were obtained by large increase in charge acceptance by optimization of additives in the negative active material, densification of the positive active material as well as increase in reaction area of the electrode plate. And further, excellent cold cranking performance applicable to frequent and fast restarting was achieved by increase in reaction area of the plate, and adoption of the positive grid in anti-corrosion property made it possible to install the battery in the engine compartment. Production and sales of a new product developed based on above technologies have already been started.