Flow batteries are an old invention that can be used in stationary applications where weight and space is not critical. In the future they will be used as a grid balance of intermitent enregy sorces like solar and wind energy. In Sweden, a lot of small family houses have some kilowatt solar on their roofs, that could benefit from a flowbattery of 10-20 kWh. Our flow batteries works with an ion fluid made out of zink and iron. As long as there are some concentration of ions left, the battery will produce energy. There are no theoretical limit for the numbers of charging and dischargings. The battery is made to last for 20 years.