KERN HFA Series Operating Manual page 20

Accu operation:
When the rechargeable battery is empty, appears on the balance's display.
Turn off balance and connect power supply unit; battery is charged.
Once the battery has been fully charged the display will show the symbol.
Insert rechargeable battery:
Unscrew battery compartment in arrow
direction.
Remove batteries including battery
mount from the device.
20 HFA-BA-e-1612