Nokia 5250 - Manual (Page 18)

3 When the device indicates a full charge, disconnect the charger from the device,
then from the wall outlet.
You do not need to charge the battery for a specific length of time, and you can use
the device while it is charging. If the battery is completely discharged, it may take
several minutes before the charging indicator appears on the display or before any
calls can be made.
Tip: Disconnect the charger from the wall outlet when the charger is not in use. A
charger that is connected to the outlet consumes power even when it is not
connected to the device.
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