As an answer to the increasing energy demand of mobile battery-powered electronic devices, we propose a new approach offering an autonomous power source. Comprising a thin film organic or hybrid solar cell connected to a Lithium-polymer (Li-polymer) battery, the so-called EURO-PSB device possesses attractive characteristics like low weight (<10 g), small thickness (<1 mm) and mechanical flexibility. Thanks to a smart interconnection between the two units, the battery is always charged with optimized voltage, independent of the illumination conditions. Such a product, compatible with roll-to-roll production processes, might open a new way for producing and storing energy for small consumption electronic devices.