The Deye SUN-K-SG04LP1-EU series are hybrid hybrid inverters designed for use with PV systems, the grid, and energy storage installations, enabling easy increases in self-consumption and providing backup power for selected circuits. A major feature is support for low-voltage batteries (lithium and lead-acid types) with intelligent integration via BMS, simplifying compatible energy storage selection and ensuring stable operation of the entire system. The presence of a 2 MPPT system is also advantageous-it allows independent management of two PV string circuits, which helps with various roof orientations and partial shading, improving energy yield in challenging conditions. The high European efficiency means better energy production in real-world operation, typical for Polish installations. Monitoring is convenient through communication (including WiFi and Ethernet) and an app, and the installer appreciates the clear display and outdoor-mounting enclosure. The series comes with required certifications for grid standards (including PN-EN 50549) and a standard warranty with an option for extension, making it suitable for both homes and small commercial premises.
Ranking
Specifications
Pros and cons
Two separate MPPT inputs (each capable of handling up to 25A, as specified in the datasheet) allow for the independent operation of two separate solar panel strings with different orientations or tilt angles. In practice, this minimizes losses due to partial shading of one section, which is particularly important in Polish rooftop solar installations with irregular geometries.
The maximum DC/AC conversion efficiency is 97.6%, and the MPPT tracking efficiency exceeds 99% - figures that place the series among the best in the range of single-phase hybrid inverters of LV class. The high European efficiency (taking into account the load profile under partial shading) directly translates into a higher annual yield in the Polish climate.
The series natively supports LiFePO4, lithium-ion, and lead-acid batteries with 24V and 48V voltages, along with BMS communication. In contrast, many competing hybrid inverters often require expensive high-voltage storage (>100V). This significantly expands the selection of compatible and more affordable energy storage solutions available on the Polish market.
The series is certified to comply with the PN-EN 50549 standard, which is required by Polish distribution system operators (DSOs) when connecting to the distribution network. The IP65 enclosure allows for external mounting without additional protection, which simplifies design and reduces installation costs.
The built-in WiFi and Ethernet communication module eliminates the need to purchase external loggers (such as those offered by Growatt or Sofar in certain models), enabling immediate remote monitoring and parameterization via the SolarmanPV app, as well as integration with energy management systems (e.g., Home Assistant via Modbus).
Users on the DIY Solar Forum report radiator temperatures exceeding 76°C under full load and ambient temperatures below 30°C. In poorly ventilated locations (closed cabinets, south-facing sunlit walls), this can affect the lifespan of components and cause the thermostat to limit power.
In emergency mode (EPS/UPS), the inverter passes the mains voltage directly to the load, without actively stabilizing it - this results in an output voltage range of 200-245V instead of the regulated nominal voltage. For sensitive devices (e.g., precision medical equipment, some appliances with electronic components), this may be a limitation that requires an additional stabilizer.
Alternatives
About the SUN-K-SG04LP1-EU series
These answers cover the whole series. Where a figure differs, the specification above is this model's own.