BATTERY, CAMERA AND CAMERA SYSTEM

A battery takes in a charge current value or a discharge current value from a current detection device at predetermined sampling intervals. Then, based upon the current value, a power consumption quantity representing the extent to which power has been consumed during a sampling interval is calculated and a total power consumption quantity is determined by sequentially adding the power consumption quantity corresponding to each sampling interval. Based upon the total power consumption quantity calculated at each sampling interval, a determination device determines as to whether or not the battery needs to be refreshed, and the determination results are transmitted to the camera. The camera informs the user that the battery needs to be refreshed if the determination device judges that a refresh operation is necessary. The sampling interval may be set longer when the power to the camera is in an OFF state compared to when the power to the camera is in an ON state.