Consult your nearest Sony dealer for replacing the built-in battery.

If you do not use your Network Walkman for a prolonged period, battery life may become shorter.
In this case, efficiency of the battery will be improved by repetition of charging and discharging.

If battery life becomes a half than the usual battery life with full-charged condition, the built-in battery needs to be replaced.
Consult your near Sony dealer for replacing the built-in battery.

Although it depends on the environment how to use the unit, generally, it is possible to repeat full charge and discharge about 500 times.

* Charge of one time is considered as charging from discharged level to full.

If battery duration becomes about half of the normal duration even though it is fully charged, it indicates the built-in battery needs to be replaced. Consult your nearest Sony dealer for replacing the built-in battery.

Remaining battery power is indicated in the OPR lamp.
The OPR lamp blinks green at about 5 second intervals during playback. As the battery power gets lower, the color of the OPR lamp changes to red. When the OPR lamp changes to red, recharge the battery.

Green -> Red ->　Quick Red Blinking (When the battery is used up, the OPR lamp blinks red quickly and a long beep is heard. You cannot operate the player.)　

It takes approximately 1.5 hours for full-charge of the battery.

* The charging time will vary depending on remaining battery power and battery condition. If the battery is charged in a low-temperature environment, the charging time will be longer.

The battery duration (continuous playback) is as:

The battery duration will vary depending on temperature and usage.