This talk will explore, how different experimental conditions impact the ageing behaviour of perovskite solar cells and which parameters are important to control during ageing experiments. We will present the design of a stress test system dedicated to perovskite stability measurements. Furthermore we will analyse the performance of 20%-efficient perovskite solar cells under simulated weather conditions based on real temperature and irradiance data of selected days during the course of a year at a location in central Europe., Presenter: Konrad Domanski