This solution is custom-designed for the roof of an 80-square-meter villa and features 24 high-efficiency 645W solar panels, a SW-12KL1 12kW European-standard off-grid inverter, and 2 SW-T512V16KWH-L2 rack-mounted lithium iron phosphate battery packs (total storage capacity of 32kWh). This setup creates a smart power supply model centered on solar energy with grid backup. Based on an average of 5 hours of effective sunlight per day, daily power generation can reach 77.4 kWh, truly achieving energy self-sufficiency, worry-free power outages, and low-carbon energy efficiency, providing stable, all-scenario power assurance for high-end residences.

How a 12-kW Off-Grid Solar-Storage System Works

The core equipment features the SW-12KL1 12kW European-standard single-phase off-grid inverter, which supports intelligent control modes such as PV priority and grid-tied operation. It serves as the cornerstone of stable energy supply for the home:
Dual MPPT design, with a maximum efficiency of 99.9% and an operating voltage range of 85V–450V, accommodates a wide range of PV modules to maximize power generation;

Rated output of 12kW, peak output of 24kVA/5s, pure sine wave output, and voltage distortion rate <3%, enabling safe operation of high-power loads such as air conditioners, underfloor heating, water heaters, and charging stations;

Automatic grid-off-grid switching with UPS-level response speed (typically 10 ms); intelligent three-way dispatch of grid, PV, and battery power—prioritizing PV when available, supplementing with the battery when PV is insufficient, and automatically switching to the grid when the battery is depleted;

Supports dual AC outputs and multi-unit parallel operation; IP54 protection; wide operating temperature range of -10°C to 55°C; space-saving wall-mounted installation; RS485/Wi-Fi remote monitoring;

Built-in comprehensive protection against short circuits, overvoltage, overloads, and surges; Type III surge protection on both the PV and AC sides, ensuring safer long-term operation.

Features two SW-T512V16KWH-L2 lithium iron phosphate batteries with a total capacity of 32 kWh, perfectly matched to the inverter:
Nominal voltage of 51.2 V, operating voltage of 43.2–58.0 V, compatible with 48 V systems, and smooth charging and discharging;

150A charge/discharge per unit, maximum 300A, cycle life ≥6,000 cycles, 90% depth of discharge, service life of over 10 years;

Supports up to 16 units in parallel for capacity expansion, with active balancing and BMS intelligent protection; supports RS485/CAN/Bluetooth/APP monitoring;

Rack-mounted design, IP20 protection rating, 5-year warranty, ensuring reliable indoor operation.

This system employs a smart complementary control logic that prioritizes solar power, uses energy storage as a buffer, and relies on the utility grid as a backup, providing 24-hour uninterrupted power supply:
Daytime: Solar Power Priority

When sunlight is abundant, the solar array directly supplies power to the entire home’s loads, prioritizing solar energy and conserving battery and utility grid resources; excess electricity automatically charges the battery until it is fully charged, with the system intelligently limiting the charge to protect the battery cells.

Evening / Cloudy or Rainy Days: Battery Backup

When sunlight is insufficient or load demand increases, the battery automatically discharges to supplement power, working alongside the PV system to support electricity consumption. This ensures stable power output, prevents voltage drops, and keeps appliances running without shutdowns or restarts.

Late Night / Prolonged Cloudy or Rainy Periods: Grid Backup

When there is no sunlight and battery levels are low, the grid automatically and seamlessly takes over to ensure uninterrupted power to loads at minimal cost; Once sunlight returns, the system immediately switches back to PV mode, prioritizing solar energy to minimize grid consumption.

Smart Complementary Operation and Protection

The inverter continuously monitors PV power, battery SOC, and load power, automatically optimizing energy flow. It provides comprehensive protection against overcharging, over-discharging, overloading, and overheating, ensuring stable, round-the-clock operation without manual intervention.

This solution is particularly well-suited for 80-square-meter detached villas that rely primarily on solar power, with grid power serving as a supplementary backup:
Households that prioritize solar power usage, aim to minimize electricity costs, and embrace a green, low-carbon lifestyle;

High-end residences located in areas with unstable power grids and occasional outages that require uninterrupted power supply;

Villas where residents prioritize quality of life and require stable operation of high-power equipment such as air conditioning, underfloor heating, smart home systems, home theater, security systems, and EV charging stations.

In practice: On sunny days, the entire home is powered by solar energy, with excess energy stored in the battery; in the evening and at night, power is supplied by the battery; during consecutive days of rain or overcast weather, when battery levels are low, the grid automatically supplements power to ensure uninterrupted service; as soon as the weather clears, solar power resumes as the primary source. Simply soak up the sun during the day, and your home will have electricity—the grid serves only as a backup, requiring almost no out-of-pocket expenses. This solution is both comfortable and economical, truly delivering freedom in electricity usage.