Salter Brecknell S122 - Manual (Page 13)

Connecting to the AC power supply.
Make sure that there is no weight on the platform before switching
on.
Plug the power supply lead into the scale.
Make sure that the battery switch is set to the internal battery.
When the scale is connected to the AC power supply you will
see a red, yellow or green charging lamp depending on the
condition of the internal battery.
Using batteries
You can either use the internal rechargeable battery or use 6 size
’D’ cell batteries (alkaline batteries are recommended).
Use the battery switch to select either the internal battery or the ’D’
cells.