How long can lithium-ion batteries be stored without recharging?

If the battery modules are connected together, i.e. installed in a cabinet, the storage times are 6 months at 25°C. This is due to parasitic losses from the BMS. If the battery modules are NOT connected together (either power or communication connections), then the storage times are 1 year at 25°C. Note: Samsung requires a ‘voltage check’ of the batteries every 180 days during storage.