Oppo HA-2 - Manual (Page 7)

12. Charging and Battery Use
This unit has a built-in rechargeable lithium polymer battery. It
should be charged before use.
VOOC Rapid Charging
Connect the USB micro-B port of the HA-2 to the supplied
VOOC Rapid Charger using the included USB A – USB
micro-B data and rapid charging cable. Plugging the charger
into a power outlet will begin charging the HA-2’s battery, and
the Charging Indicators on the side of the unit will start to
blink. It may take a few seconds to enter the rapid charging
mode, which is indicated by the Charging Indicators quickly
blinking. When the battery is almost full, rapid charging will
change to normal charging automatically, and the blinking
speed of the Charging Indicators will slow down.
Normal Charging
The unit can also be charged by connecting the USB micro-B
port to a USB port on a Mac or PC. The Charging Indicators
on the side of the unit will blink when the unit is being
charged. Rapid charging is not possible using this connection
method.