MULTI-PACK CURRENT LIMIT ROLL UP

A modular battery system includes a battery bus, multiple battery packs connectable in parallel to the battery bus to provide a system current, and a battery system controller. A battery pack includes multiple battery cells and provides a battery pack current to the battery bus. The battery system controller is configured to determine whether individual battery packs are online or offline, receive individual battery pack current limits of online battery packs and set a system level current limit of the battery system, determine system current and individual battery pack currents, compare the individual battery pack currents to their respective individual battery pack level current limit, update the system current limit according to the comparing, and scale a current demand for the individual battery pack currents using proportions of the measured system current and the updated system current limit.