The Cerbo can have several battery monitors connected to independent batteries. You then have to choose one as your master battery, typically the house battery that is your main power source and has the inverters, solar etc. and is the one shown on the main screens with battery SOC, charge current and volts etc. The other batteries are then reported on the device list or by clicking on the main battery icon on the overview screen. None of the info from the secondary battery gets taken into account in the main battery system.