Do I need a photovoltaic system to have a battery?

Not at all. However, solar cells and batteries work very well together and in symbiosis create very good profitability. Solar cells generally produce electricity when the price is highest, i.e. during the day, which means that you can either charge when you have a surplus of production to use when the sun is not shining. At present, it is cost-effective for private individuals to install batteries and solar cells at the same time as the installation is then eligible for a 50% tax reduction through green technology.