Deye 2.5kW SUN-BK250-2.56KWH-EU-AM4-32L Hybrid LV 1 phase inverter AIO

Deye SUN-BK250-2.56KWH-EU-AM4-32L Micro Hybrid ESS

The SUN-BK250 is not a traditional string inverter, but rather a compact, integrated micro hybrid energy storage system (ESS): a 2.5 kW hybrid inverter and a 2.56 kWh LiFePO4 battery housed in a single IP65 enclosure. The system thus simultaneously serves as both an inverter (DC/AC conversion, grid management) and an energy storage unit, enabling it to operate independently without additional equipment.

Deye SUN-BK250-2.56KWH-EU-AM4-32L Micro Hybrid ESS

The SUN-BK250 is not a traditional string inverter, but rather a compact, integrated micro hybrid energy storage system (ESS): a 2.5 kW hybrid inverter and a 2.56 kWh LiFePO4 battery housed in a single IP65 enclosure. The system thus simultaneously serves as both an inverter (DC/AC conversion, grid management) and an energy storage unit, enabling it to operate independently without additional equipment.

The product falls into the low-power, plug-and-play category: it can be plugged into a standard outlet and is primarily intended for balcony solar systems (balcony PV), small-scale residential self-consumption, and portable applications, rather than large hybrid inverters designed to power an entire home.

What can it be used for?

It operates in three modes, which determine its typical uses. In hybrid, grid-connected mode, you use it to increase self-consumption: it stores the energy generated during the day and releases it when the household is actually using it. In off-grid mode, it functions as a standalone, portable power source—for camping, mobile locations, or temporary power supply.

The third option, AC-connected mode, is the most common upgrade scenario: it can be added to an existing balcony-mounted solar system (with a microinverter), expanding it with storage without requiring a complete overhaul of the existing installation. It’s also a viable option for small C&I sites or leased properties where major construction isn’t possible.

How does it work?

The unit converts DC power from the solar panels into 230 V AC, while charging the built-in battery and managing the flow of energy to and from the grid. The zero-export function controls the system wirelessly with low latency, making it suitable for use even where feeding energy back into the grid is not permitted or undesirable—the generated energy is used for self-consumption and stored in the battery.

In the event of a power outage, it provides UPS-level backup: the switchover between grid and off-grid operation takes ≤4 ms, which is imperceptible to most sensitive devices (routers, computers, refrigerators). The 6 configurable charging/discharging time slots allow you to tailor operation to time-of-use or dynamic rates, charging during off-peak hours and discharging during peak hours.

Technical and System-Level Benefits

The 32L version accepts up to 5,760 W of PV power on the solar side via 4 independent MPPT inputs—this enables the management of multiple panel strings with different orientations, which is a real advantage for balcony and smaller rooftop systems. With a peak efficiency of 96.5% and MPPT efficiency of >99%, conversion losses are low, and thanks to 99% module compatibility, it can be paired with most panels on the market.

At the system level, IP65 protection allows for outdoor installation, and the 10-year warranty ensures a long service life. If you outgrow the built-in 2.56 kWh capacity, the system is expandable: up to 3 units can be connected in parallel (max. 7.5 kW), and storage capacity can be increased with external AE-F2.56 battery modules.

Differences

Within the BK series, the main difference is the rated AC power: BK80 = 800 W, BK160 = 1600 W, BK200 = 2000 W, BK250 = 2500 W. The BK250 is the top model in the series, with a total output of 2.5 kW—this is the recommended choice if the combined load of the appliances you wish to back up approaches this level.

The 18L and 32L models differ in their PV input: the 18L accepts a maximum panel power of 4,400 W, while the 32L accepts a maximum of 5,760 W, with a higher allowable input current. If you want to connect a larger array of panels, the 32L is the better choice—this is the version to choose.

Important to Know

This is a 2.5 kW / 2.56 kWh microgrid system; it is not designed to power an entire house. The total power of simultaneously operating loads must remain below 2,500 W, and the 2.56 kWh capacity is primarily sufficient for bridging the power supply to critical loads for shorter periods (e.g., a router and lighting for several days, a refrigerator for 1–2 days, and larger loads for much shorter periods). Single-phase (L+N+PE, 230 V) device.

This is the right choice if the goal is to increase self-consumption and provide a basic backup supply, rather than complete grid independence.

SOLARKIT Reviews

We recommend the BK250-32L to those who want to add storage and backup power to their existing balcony-mounted or smaller solar systems in a simple way, without major installation work. Thanks to its plug-and-play installation, IP65 rating, and wireless zero-point feed-in, it’s a viable option even in situations where a traditional hybrid inverter would be oversized or difficult to obtain permits for.

In practice, the 32L version is preferable to the 18L if you plan to connect a higher panel capacity; the full 2.5 kW BK250 is recommended if the load of the battery-backed appliances is in the upper range. For those who want to take an entire house off the grid, we recommend a larger hybrid inverter and battery pack instead—this product is a smart choice in the entry-level/supplemental segment.