Oppo A54 5G Notes On Usage page 26

■ Internal battery
(The internal battery of the product is a lithium-ion
battery)
The internal battery is not fully charged at the time
of purchase. Charge the internal battery before use.
Charge the internal battery if you have not used the
product for a long time.
• In summer, the capacity of the internal battery decreases and the
usable time becomes short under extreme high or low temperature
environment, for example, leaving the product inside a tightly
closed car (automobile). Also, that shortens the internal battery life.
Use the product at room temperature as much as possible.
• The internal battery gradually discharges after being charged even
if the product is not used. The internal battery may discharge
completely after long time no use. Charge before using.
• The internal battery is a consumable item. If the functions are not
recovered even when it is charged, for example, the usable time
remains extremely short, the internal battery is at the end of service
life, so stop use. Because of the built-in battery, the product must
be kept at au shop/au Style etc. to repair for a charge. And you
may not be able to use the product during certain period of time.
Please be forewarned. Note that the length of service life varies
depending on the usage condition etc.
• The internal battery sometimes swell up as they approach the
end of their service life. This is due to the properties of lithium-ion
batteries, and is not a problem in terms of safety.
■ Charging equipment
• Do not wind up a power cable of the specified charging equipment
(sold separately) around the adapter unit. Do not forcibly bend the
connection part of a plug/connector and a power code of charging
equipment. Do not place a heavy object over a cord of adapter or
charging equipment (sold separately), or do not apply force to the
cord by pulling etc. May cause a malfunction.
• When disconnecting a power plug of the specified charging
equipment (sold separately) from a power outlet, grasp the power
plug. If you pull the cord to disconnect, the cord may be damaged.
24
Safety Precautions