Sony Cyber-shot DSC-W560 Handbook page 136

On the internal rechargeable backup battery
This camera has an internal rechargeable battery for maintaining the date and time and other settings
regardless of whether the power is on or off.
This rechargeable battery is continually charged as long as you are using the camera. However, if you use
the camera for only short periods, it discharges gradually, and if you do not use the camera at all for about
one month it becomes completely discharged. In this case, be sure to charge this rechargeable battery before
using the camera.
However, even if this rechargeable battery is not charged, you can still use the camera, but the date and time
will not be indicated.
Charging method of the internal rechargeable backup battery
Insert charged battery pack in the camera, and then leave the camera for 24 hours or more with the power
off.
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