Patent attributes
A battery device includes a storage battery unit, a current sensing unit, a temperature sensing unit, a storage unit and a processing unit. The current sensing unit detects load current. The temperature sensing unit detects the battery temperature of the storage battery unit. The storage unit stores a cycle number, multiple threshold intervals, and multiple charging voltage values. According to the load current, the battery temperature and the cycle number, the depth of discharge of the storage battery is acquired. The storage unit stores the load current, the battery temperature and the cycle number. The processing unit operates a charging procedure. The charging voltage value corresponding to the working threshold interval is selected to be the main charging voltage value, and the DC voltage that is identical to the main charging voltage value is used to perform a constant voltage charge for the battery unit.