The Deye SUN-BK 2.56kWh is a plug-and-play micro hybrid energy storage system that lets balcony solar users store, manage, and back up their own power — without a roof, without an electrician, and without compromise. It combines a microinverter, a 2.56kWh LFP battery, and a BMS in a single compact, wall-mountable unit designed for the European market.
The SUN-BK delivers 2.56kWh of LFP storage with 6,000+ cycle life, UPS-grade backup with <4ms grid switchover, AC coupling for integrating with existing balcony micro-inverters, and scalability up to 102.4kWh via expansion packs. Smart scheduling via the DEYECLOUD App allows up to 6 programmable charge/discharge periods per day for peak-tariff savings.
The SUN-BK250 supports 2,500W AC output, 2.56kWh LFP storage, and 4 independent MPPT channels. Choose the 18L version for up to 4,400W PV access power with 18+18+18+18A PV operating current, or the 32L version for up to 5,760W PV access power with 32+32+32+32A PV operating current. It operates from -10 C to +50 C, carries an IP65 weatherproof rating, achieves up to 96.5% DC-AC efficiency, and can expand to 102.4kWh with compatible AE-F2.56 battery packs.
The SUN-BK is compatible with 80W to 250W micro-inverters and connects via AC coupling to most European balcony micro-inverter brands — no rewiring required. It integrates natively with the Deye Wireless CT (SUN-SMART-CT01) via LoRa for zero-export control, and with the DEYECLOUD App for remote monitoring and smart scheduling.
The SUN-BK is designed for balcony or outdoor wall installation with a compact footprint under 1/4 m². The split-body design separates the inverter and battery modules for easier handling. AC coupling to an existing balcony system can be performed by a qualified electrician. The DEYECLOUD App guides the commissioning process step by step.
The Deye SUN-BK carries CE marking under the Low Voltage Directive 2014/35/EU and EMC Directive 2014/30/EU, IEC 62619 lithium battery safety certification, UN38.3 transport certification, and complies with EN 50549-1 and VDE-AR-N 4105 grid connection standards for Germany. EU Declaration of Conformity documents are available at deyeinverter.com.
Both are Deye all-in-one balcony storage systems, but the SUN-BK is designed for users who need more. The SUN-BK delivers 2.56kWh of storage (vs 2kWh), 2,500W AC output (vs 800W), and scales up to 102.4kWh via expansion packs (vs 10kWh). It also supports 4 independent MPPT channels for larger or more complex PV setups. If you're starting small, the AE-FS2.0-2H2 is a great entry point — the SUN-BK is the natural next step when you're ready to go further.
The Deye SUN-BK includes a 10-year product warranty — the longest in its class. Deye's European support team provides technical assistance via email and the DEYECLOUD App. As an established solar inverter manufacturer with over 10 years of industry experience, Deye provides long-term spare parts and firmware support for all EU-sold products.
The Deye SUN-BK ships across the European Union from Deye's European warehouse. VAT is included in the price. Standard shipping takes 3–7 business days depending on destination. A 14-day return policy applies to all orders.
The SUN-BK supports up to 40 AE-F2.56 expansion packs connected in parallel, for a maximum total capacity of 102.4kWh. This makes it the most scalable balcony ESS available — you can start with 2.56kWh today and grow as your energy needs increase, all using the same base inverter unit and the same DEYECLOUD App.
