Hyundai Sonata Hybrid 2021 Owner's Manual page 23

Foreword
Engine generation/motor drive
The engine charges up the high-voltage
battery. The motor power is used to drive
the vehicle.
(Engine → Battery → Wheel)
Engine generation/regeneration
The engine and regenerative brake
system charges up the high-voltage
battery.
(Engine & Wheel → Battery)
1-20
Engine brake/regeneration
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The engine braking is simultaneously
used to decelerate the vehicle and to
charge up the high-voltage battery.
(Wheel → Engine & Battery)
Start engine to avoid battery
discharge
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If the engine is not turned on with
the Engine Start/Stop button in ACC
or ON for a while, the battery can be
discharged. Please turn on the engine to
prevent 12V battery from discharge.
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