Stacked LiFePO4 home energy storage batteries are widely used for small residential PV matching and power outage backup. Single module capacity is 5.12kWh (51.2V 100Ah), matched with a 5kW hybrid energy storage inverter. Up to 4 modules can be stacked, with maximum expandable capacity of 20.48kWh. Continuous maximum load is 5kW, and short-time peak load reaches 7.5kW. Adopting safe LFP cells, the plug-and-play modular design avoids complicated wiring renovation. It supplies lighting, refrigerators and routers, realizes surplus PV power storage and peak-valley arbitrage. Extra modules can be added later to expand capacity, meeting basic energy reserve demands of ordinary families.