The invention provides a battery managing system, which includes: a charging/discharging unit, configured to operably charge/discharge the battery; a sensing unit, configured to operably sense a voltage, a discharging current and a discharging duration time of the battery during discharging the battery; and a calculating unit, determining a charge/discharge capability of the battery according to the voltage, the discharge current, the discharge duration time, and temperature of the battery. According to the present invention, the battery managing system can be included in a chip insides each cell of the battery for early indication of poor reliability, so that the chip can be used to determine the charge/discharge capability or to prevent explosion.