Ventilogic LS:

Care of the internal battery:
Fully charge the battery before carrying out the following steps. Leave the device connected to the power supply for at least 15 hours. We recommend discharging the battery once a month by operating the device until the alarm Battery capacity critical appears (approx. 25 % capacity remaining). Then recharge the battery until full by operating the device from the power supply. This boosts the shelf life and the service life of the battery. If the battery lasts less than 45 minutes if having previously been at full capacity, have the battery replaced by the manufacturer, Weinmann, or by specialist staff expressly authorized by the manufacturer. We recommend that the device remain connected to the power supply at all times, except for the monthly discharge procedure. This ensures that the internal battery is always fully charged and ready to use.