MSW Motor Technics BLS-A001 Manual De Instrucciones página 25

3.3.
Working with the unit
3.3.1 CHECKING / CHARGING THE BATTERY
The unit is shipped with a fully charged battery, but you should
nevertheless check the battery charge status before operating the
unit for the first time.
To do this, press the button with the battery icon on the battery
housing - as shown in the images below:
Illuminated 3 lights indicate a fully charged battery.
If none of the lights is illuminated, the battery is discharged and
needs to be recharged.