The SMA Sunny Boy STORAGE series comprises battery inverters (AC-coupled) designed for use with energy storage systems in consumer installations - particularly where PV systems are already operational, aiming to increase self-consumption and energy independence. Intelligent management of energy flows between the home, the grid, and the battery, along with stable operation under varying loads, is key. Unlike PV inverters, the Sunny Boy Storage lacks an MPPT for DC modules, so it does not optimize string performance regarding shading or different orientations. Instead, it focuses on efficient AC-DC conversion during battery charging and discharging. In practice, the high European efficiency means fewer losses under typical operating conditions, resulting in more real energy available at home. Additionally, features include monitoring via Sunny Portal and SMA Energy App, offering insights into consumption and storage status, along with communication (e.g., LAN/WiFi depending on the version). The series is primarily targeted at single-family homes and small commercial properties, where compatibility with selected energy storage systems, conformity certificates, and a reasonable manufacturer warranty matter.
Ranking
Specifications
Pros and cons
The AC-coupled architecture allows a battery energy storage system to be added to any existing PV installation without replacing the solar inverter. This is a key advantage in the retrofit market, where swapping out the PV inverter would incur a cost of PLN 2,000-5,000 and potentially void the existing warranty.
The SBS is among the first battery inverters on the market (since the 2nd generation) to support multi-string battery connection - the ability to simultaneously connect up to three separate high-voltage battery modules (e.g., BYD Battery-Box Premium HVS/HVM or LG Chem RESU-H, 300-600 V DC range). This provides the flexibility to incrementally expand storage capacity without replacing the inverter.
The IP65-rated enclosure allows installation on an exterior wall or in a garage without an additional protective enclosure, reducing installation costs compared to IP54-rated devices (e.g., select Victron or Fronius models) that require an outdoor cabinet or indoor siting.
The standard 5-year warranty extends to 10 years upon registration in Sunny Portal, with an optional extension to 20 years. By comparison, most AC-coupled competitors (e.g., GoodWe GW-BT series) offer 5-10 years with no extension option, making the SBS more attractive for long-term investments.
An integrated web server and native integration with the Sunny Portal platform and SMA Energy App provide real-time visibility into energy flows, battery SOC, and self-consumption statistics - with no need to purchase a separate energy manager (market value ~PLN 300-600). SMA also offers proactive service notifications upon detection of operational anomalies.
In an AC-coupled architecture, PV energy undergoes three conversion stages (DC→AC→DC→AC), whereas DC-coupled solutions (Fronius Symo Hybrid, SolarEdge StorEdge) require only two. The combined efficiency of the SBS (~96.5%) with a typical PV inverter (~97%) yields approximately 93.6% round-trip efficiency - 3-4 percentage points below peak DC-coupled systems, which achieve 96-97%.
The SBS is a single-phase device; in backup mode (Secure Power Supply), it supplies only one phase at up to 2 kW (SPS mode) or up to 3.7 kW from the battery. In homes with a three-phase grid connection or three-phase loads (heat pump, EV charger), additional switching automation or a second inverter is required, increasing the overall system cost.
Alternatives
StorEdge AC Coupled Single Phase Inverter (HD‑Wave) – SE3680H / H3680SE
3.68 kW
98.8%
-
7.8 kg
18.2 kg lighter
About the SUNNY BOY STORAGE series
These answers cover the whole series. Where a figure differs, the specification above is this model's own.