Samsung SCH i830 - Manual (Page 31)

Section 2: Understanding Your Phone 31
Battery
Section 2
Note: Long backlight settings, searching for service, vibrate mode and
browser use affect the battery’s talk and standby times.
There is also an internal backup battery that saves all
settings in the phone if the regular battery is discharged.
An internal backup battery needs an initial charge of 24
hours.
The internal battery maintains data for about four hours.
Perform ActiveSync operations or a backup utility
frequently to avoid loosing any information in case the
battery is fully discharged. For more information see
"ActiveSync®" on page 152.