Sony MZ-DH10P Operating Instructions Manual page 15

When the battery is completely charged, the
CHG lamp goes off.
If the battery is completely drained at the
start of charging, it will take about one hour
for the CHG lamp to go off and the battery to
become sufficiently charged to allow use of
the player. When the CHG lamp goes off, the
battery is charged up to 80%. After 2 more
hours of charging, the battery will be fully
charged.
If the CHG lamp turns off after a short
time, the rechargeable battery is sufficiently
charged.
When using the player powered by the AC
power source
You can use the player without draining the
rechargeable battery.
1 Connect the AC power adaptor to the USB
cradle and the AC power adaptor to a wall
outlet.
2 Place the player on the USB cradle and
push it in firmly.
To remove the player from the USB cradle
Press RELEASE.