I am trying to optimize a charging station for EVs in matlab with intlinprog, which is connected to a PV-Modul, to an system storage systeme and to the network grid. I am using different Storage technologies (Lithium, Lead acid and flywheel). I have issues to simulate for some charging scenarios with time resolution of 15 minutes (PV and load data). The charging scenarios are 350kW with 3 Charging points (total energy demand for a year 665 MWh); 150 kW with 12 Charging points (allover 253.58 MWh)and 11kW with 25 Charging points (for a whole year 83.8 MWh). When the demanded energy is lower, the model runs slower, and when there is higher self-discharge, the model also slows down. The simulation varies 3h30 for Li and first scenario (so lowest self discharge and highest Demand) to nearly a day for Flywheel and 11 kW. Can someone help me, explain to me why?