The Battery system (ongrid) to be simulated is defined on the _Battery system (ongrid)_ page. The navigation page can only be selected for corresponding grid-connected PV systems. A battery system consists of the battery inverter, the batteries and the charge control. Charge control and battery inverter are usually combined in one device. Depending on the system, a PV inverter with MPP tracker can also be integrated, but these are defined in PV*SOL® as independent devices on the page Inverters.