Wall-mounted LiFePO4 batteries adopt ultra-slim compact bodies for direct wall mounting, saving floor storage space and fitting narrow areas such as balconies, garages, power distribution rooms and store walls. Single person can finish transportation and fixation without dedicated battery rooms, simplifying construction and shortening installation time. It supports parallel connection of multiple units for flexible capacity expansion; users can add batteries gradually according to PV capacity and power load without one-time high investment. Built-in universal CAN/RS485 communication protocols are compatible with over 20 mainstream PV inverters for seamless matching with new and old PV systems. Modular independent design ensures single-unit failure won’t crash the whole energy storage system, easy for later expansion and replacement, meeting power demands of small apartments, villas and retail stores of various scales.