Small-sized balcony PV systems feature low installed power, making 2–4kWh wall-mounted energy storage the ideal match. Slim and wall-hung, it saves precious balcony floor space, perfectly fitting enclosed balconies in high-rise apartments. It supports dual charging: self-generated PV power and grid backup. Electricity generated by balcony solar panels in the daytime is stored for basic appliances like lights, fridges and routers at night. The smart BMS adjusts charging power dynamically to avoid overloading small balcony PV modules. No civil reconstruction is needed for quick wall installation. It cuts daily power bills and supplies emergency power during outages, serving as the top entry-level storage for high-rise balcony photovoltaic systems.