A photovoltaic module or photovoltaic panel is a packaged, interconnected assembly of photovoltaic cells, also known as solar cells. The photovoltaic module, known more commonly as the solar panel, is then used as a component in a larger photovoltaic system to produce electricity for commercial and residential applications. Because a single photovoltaic module can only produce a limited amount of power, many installations contain several modules or panels known as a photovoltaic array. A photovoltaic installation typically includes an array of photovoltaic modules or panels, an inverter, batteries and interconnection wiring. Photovoltaic systems are used for either on- or off-grid applications.