59
Preparations
Backup battery
The unit uses a backup battery (rechargeable battery) to operate the clock.
While power to the unit is on, the backup battery will be charged. It will
also be charged while power to the unit is off if external power is connected.
The relationship between charging time and retention period is shown below.
A full charge of the backup battery is achieved after 24 hours.
Charging time
Retention period
1 hour
2 days
12 hours
30 days
24 hours
45 days
Use the AC adapter when connecting external power for battery charge while
the unit is turned off. The service life of the backup battery is limited. You
should have the battery replaced about once every fi ve years. Please contact
your supplier.
Note
The charging time, retention period and service life
of the backup battery may vary depending on the
operating condition.
When the backup battery is old, the retention peri-
od will be shorter.
Summary of Contents for DA-21
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