SMA Sunny Boy Mono 4 kW Grid-Connected Inverter – SB4.0-1AV-41

SMA Sunny Boy SB4.0-1AV-41 Grid-Connected Inverter – Maximum output, anti-shading and scalability for homes

The SMA Sunny Boy SB4.0-1AV-41 is a 4, 000 W single-phase grid-connected inverter from SMA’s AV-41 generation — the successor to the Sunny Boy 3000–5000TL, which has been used successfully worldwide. It represents a significant leap in quality compared to the previous generation: two independent MPPT trackers instead of one, SMA’s patented ShadeFix technology integrated as standard for optimisation in shaded conditions, native compatibility with TS4-R optimisers, and a scalable architecture allowing SMA energy management and storage solutions to be added at any time. With a rated power of 4,000 W, it remains below the Synergrid limit of 5,000 VA single-phase in Belgium and is ideally suited to residential installations with 10 to 12 solar panels.

2 independent MPPT trackers: maximum flexibility for complex rooftops

The SB4.0-1AV-41 features 2 independent MPPT trackers, each accepting up to 2 strings and a maximum current of 15A per input. The SB4.0’s MPPT range extends from 140 to 500 Vdc, with a maximum input voltage of 600 Vdc and a rated voltage of 365 Vdc. The minimum start-up voltage is 125 Vdc (minimum voltage 100 Vdc). The maximum rated DC power is 7,500 W, representing an overcapacity ratio of 187% — one of the highest on the market for a residential inverter — allowing a PV array significantly larger than the inverter’s rated power to be connected to maximise annual output. The two independent MPPT trackers allow two different roof orientations or pitches (east/west, mixed pitches) to be optimised separately, without the underperformance of one string affecting the other.

SMA ShadeFix: the patented anti-shading software included as standard

SMA ShadeFix is a patented software developed by SMA and integrated as standard in the Sunny Boy SB4.0-1AV-41. It represents a major advancement over the Sunny Boy 1.5’s OptiTrac algorithm: whereas OptiTrac Global Peak periodically scanned the power-voltage curve to find the global maximum, ShadeFix goes further by continuously analysing the shading signature of each string to dynamically determine the optimal optimisation strategy. In practical terms, ShadeFix maintains each string at the global maximum power point, even when shading creates multiple local maxima on the IV curve. This optimisation is transparent to the user and results in a production loss of less than 0.2% due to the algorithm itself. For residential rooftops with more complex or permanent shading (central chimney, nearby tree, overlapping panels), the integrated TS4-R communication allows SMA optimisers to be selectively added to the most affected panels, without replacing the inverter.

Dynamic active power limitation: making the most of every watt produced

The SB4.0-1AV-41’s dynamic active power limitation function is an advanced feature that allows the power fed into the grid to be adjusted in real time according to the household’s instantaneous consumption. When a household appliance is switched on (washing machine, dishwasher, water heater), the solar power is automatically directed towards that appliance rather than being fed into the grid. This function reduces reliance on the grid and improves the self-consumption rate without requiring a storage battery. It is particularly effective when combined with the SMA Energy Meter (sold separately), which measures the household’s energy flows in real time.

TS4-R communication: selective optimisation of shaded panels

The SB4.0-1AV-41 comes with TS4-R communication (Technology for SMA Rapid Shutdown and Power Optimisation) as standard, allowing SMA TS4-R-O optimisers to be connected directly to the panels most affected by shading. Unlike full optimisation systems that require an optimiser on every panel, the selective ShadeFix + TS4-R approach allows optimisers to be placed only on the panels that are actually problematic, thereby reducing installation costs whilst maximising yield gains on shaded panels. This combined architecture is the most cost-effective solution for partially shaded residential rooftops.

Transformerless: lightweight, efficient, reliable

The SB4.0-1AV-41 is a transformerless inverter. This design contributes to a maximum efficiency of 97.0% and a European efficiency of 96.5%, as well as the inverter’s compact size (435 × 470 × 176 mm) and its modest weight of 17 kg — allowing for installation by a single person. To compensate for the lack of galvanic isolation, the SB4.0-1AV-41 incorporates a fault current monitoring unit sensitive to all currents (AC and DC), protection against DC reverse polarity, and resistance to AC short circuits, in accordance with safety requirements for transformerless inverters (protection class I, overvoltage category III according to IEC 60664-1).

Scalable architecture: energy storage and management at all times

One of the strategic advantages of the Sunny Boy SB4.0-1AV-41 is its native compatibility with the SMA ecosystem. A system equipped with the SB4.0-1AV-41 can be expanded at any time with:

• An SMA Energy Meter for measuring energy flows and optimising self-consumption in real time.
• An SMA storage system (Sunny Boy Storage or Sunny Tripower Storage) to add a battery to the installation without replacing the existing grid-connected inverter.
• An SMA Data Manager or Webconnect module for remote monitoring via the SMA SunnyPortal.
• TS4-R optimisers to selectively manage the most shaded panels.

This scalability is particularly valuable in a context where a household’s energy needs may change (electric vehicle charging, heat pump, home extension), allowing the initial investment to be protected whilst gradually adapting the system.

SUNCLIX DC connection: quick and secure installation

The SB4.0-1AV-41 uses the proprietary SUNCLIX DC connection system from SMA and Phoenix Contact for both MPPT inputs. This quick-connect system allows DC cables to be connected in seconds without tools, with a mechanical lock ensuring a secure and watertight connection. The AC connection is made via a standard AC plug. Wall mounting is achieved via accessible external connections, facilitating installation and subsequent maintenance work.

Natural convection: zero maintenance, 25 dB(A)

The SB4.0-1AV-41 is cooled exclusively by natural convection — without a fan. The typical noise level is 25 dB(A), virtually inaudible even when installed near living areas. The absence of moving parts eliminates failures caused by fan wear and reduces maintenance to zero for the thermal section. The 4K4H climate classification (according to IEC 60721-3-4) guarantees resistance to harsh outdoor conditions, and the maximum permissible relative humidity is 100% — the inverter can operate in environments with high humidity.

Remote monitoring: SMA SunnyPortal

The SB4.0-1AV-41 is compatible with the SMA SunnyPortal monitoring portal via the addition of an optional communication module — the Webconnect (Wi-Fi) module or the SMA Data Manager, depending on the desired configuration. Monitoring includes real-time production tracking, historical production curves, yield reports and alerts in the event of anomalies. Comprehensive guides on Wi-Fi setup and reconnection after changing the modem are available in the Wattuneed blog posts dedicated to SMA inverters. Communication between the inverter and the monitoring modules takes place via the integrated data interface.

Night-time self-consumption and built-in protections

Outside of production hours, the SB4.0-1AV-41 consumes 5.0 W in night-time standby mode. All the protection features required for a transformerless grid-connected inverter are integrated: DC disconnect device, earth fault monitoring, grid monitoring (anti-islanding), DC reverse polarity protection, AC short-circuit resistance, and a fault current monitoring unit sensitive to all currents. The operating temperature range is from -25°C to +60°C, and the acceptable AC nominal voltage range is 180 to 280 Vac.

Key technical specifications