Datalogic ELF User Manual page 25

BATTERIES AND MAINTENANCE
In order to maximize operating autonomy, the Elf checks its
battery level at all times. If the battery is not sufficiently charged,
the Elf will not turn on when the ON/OFF Power button is
pressed.
In this case, either substitute a sufficiently charged battery, insert
NOTE
the Elf into a powered cradle, or plug it into a wall charger.
To maximize battery life, turn off radios when they are not
needed.
NOTE
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