KOSTAL Solar App The free KOSTAL Solar App offers professional monitoring of your photovoltaic system. You can conveniently and easily retrieve all functions from your smartphone or tablet at any time. To set up and use the app, you need access to the KOSTAL solar portal and an inverter installed there. For the login of the app the same access data as for the solar portal are needed. General information With the KOSTAL Solar App, you can now conveniently monitor your solar systems while you are