Household energy storage system case

Beijing Mujiaoyu·Zixiagu Single-family Villa 12 kW / 25.6 kWh Optical Storage System (Commissioned in 2023)

1 Project background

• Location: Changping Mountain District, Beijing, 50 km away from the city. The mains power supply is unstable and there are frequent power outages in summer and winter.

• Construction area: about 500 m², suitable for a family of 4, including central air conditioning, floor heating, fresh air, swimming pool pump, and charging pile

• Electricity consumption characteristics: 31 879 kWh throughout the year, including 19 513 kWh in peak periods; owners’ demands – non-stop power supply during power outages, peak shaving and valley filling, and zero-carbon demonstration

2 Photovoltaic system

• Roof area: 51 m² (unshaded south)

• Component: LONGi Hi-MO 5 single crystal 550 W × 22 pieces

• Installed capacity: 12.16 kWp

• Annual power generation: ≈ 15 000 kWh (Beijing irradiation 1 350 kWh/kW)

• Inverter: 12 kW three-phase hybrid inverter (compatible with off-grid)

3 Energy storage system (core data)

Subsystem Parameter Description

Battery model Lenercom LC-E2-1225 lithium iron phosphate module

Rated capacity 25.6 kWh / 12 kW 0.5 C continuous

Battery structure 1P16S module → 8 modules connected in series into a cluster → 2 clusters connected in parallel Can be maintained independently

Voltage range 44.8–54.4 V (cluster end) → 380–480 V (DC link)

Cycle life 6000 times @25 ℃, 0.5 C, 80% EOL

BMS level three (BMU-BCU-BA), SOC accuracy ≤ 2%, active balancing

Thermal management air cooling + intelligent temperature control (15–30 ℃)

Backup switching < 20 ms off-grid switching, UPS level response

Protection grade IP65 indoor cabinet, noise ≤ 45 dB

Communication RS485 / CAN / Wi-Fi, access to mobile App for remote monitoring

4 Operation strategy

• Summer: peak discharge 20 kWh from 06:00–22:00, valley charging 15 kWh from 22:00–06:00

• Winter: Floor heating load is high, set 70% battery reserve power

• Blackout mode: critical loads (security, refrigerators, fish tanks, lighting) 3 kW for 8 hours

• Annual electricity bill savings: approximately US$1,624 (≈ RMB 12,000)

5 Construction and operation and maintenance

• Cabinet size: 600 × 550 × 1 200 mm, wall-mounted on the side wall of the garage, area < 0.5 m²

• Grid connection: 220 V single-phase + 380 V three-phase dual circuit, supports anti-reverse flow

• Warranty: 10 years on inverter, 10 years or 6000 cycles on battery

• Remote operation and maintenance: Cloud OTA upgrade, failure response within 24 hours

6 Environmental protection and added value

• Annual carbon emission reduction: ≈ 7.5 t CO₂

• Value of backup power supply: avoid losses due to power outages in refrigerators, fish tanks, and security guards

• Housing premium: Green low-carbon label brings about 3–5% premium on second-hand housing