The balance of system (BOS) encompasses all components of a solar system other than the photovoltaic panels. This includes wiring, switches, a mounting system, one or many solar inverters, a battery bank and battery charger.
Balance of Solar PV Systems (BOS) A Solar PV Balance-of-System or BOS refers to the components and equipment that move DC energy produced by solar panels through the conversion system which in turn produces AC electricity.
The Balance of System components of a photovoltaic system, can be understood as balancing the DC power-generating subsystem of the solar array (left side) with the power-using side of the AC-household appliances and the utility grid (right side).
The Balance of System (BoS) refers to all of the system components that are necessary to integrate the photovoltaic panels with the building load and/or the electric utility supply. The direct-current output of the solar array is not compatible with building loads and the grid, and isn't safe for direct use either.