Propulsion batteries will become increasingly important for powering ships and will reshape port infrastructure. While many batteries are no longer suitable for onboard use, they can still be reused in other applications. Using these retired batteries for shore power improves both cost efficiency and sustainability. The “2nd2Sea” project explores this potential by developing an AI-based battery management system (BMS) at the module level to accurately assess battery condition and reduce complexity in selecting module and cell technologies. In parallel, the project investigates flexible battery module designs and develops power electronics and an energy management system (EMS) that can intelligently integrate and optimize modules of varying quality. This project will be conducted at CAU Kiel.