Standard capacity of household energy storage batteries ranges from 5kWh to 30kWh, among which 10kWh, 15kWh and 20kWh are mainstream models. Small apartments adopt 5–10kWh for lighting and refrigerators; ordinary houses choose 10–20kWh to power all household appliances with solar storage; villas can stack modules to expand capacity to 25–30kWh. Residential batteries adopt low-voltage design with 3kW–12kW power to eliminate high-voltage risks and support parallel expansion, forming standard capacity collocation for household photovoltaic systems.