The SMA Sunny Island is the battery inverter designed for off-grid and backup: it powers your home from a battery, on an off-grid site or during a grid outage. wendows sizes, installs and configures this autonomy system, and remains your point of contact for warranty and after-sales.
Autonomy isn't a universal need: it answers specific situations. Here are the configurations we study most often in Belgium, sized to your objective.
The Sunny Island switches to the battery during a grid outage: the essential circuits stay powered. A safeguard for areas prone to outages.
For a site not connected to the grid, the Sunny Island builds a standalone grid powered by the panels and the battery. Electricity without a connection.
The Sunny Island is a battery inverter: it needs storage sized to hold the targeted autonomy. The inverter + battery pair framed at the study.
The state of the autonomy and the battery is tracked via Sunny Portal: charge level, switchovers and alerts to manage the system with peace of mind.
Beyond the brand, it's the ability to build a standalone grid that sets this inverter apart. The key points of the Sunny Island, sized by our teams.
The Sunny Island isn't a classic panel inverter: it's a battery inverter that builds and maintains a standalone grid, powered by the storage.
It works on an off-grid site or in backup mode: it switches to the battery to keep the essential circuits powered during an outage.
The power is sized according to the uses to hold in autonomy and the capacity of the battery bank. It all starts from the autonomy objective defined at the study.
Manufacturer warranty on the inverter, often extendable depending on the model. wendows handles the liaison and the intervention if needed.
Supervision of the autonomy state and the battery: charge level, switchovers and alerts. The tool that makes the system legible and eases after-sales.
The Sunny Island needs storage sized to hold the targeted autonomy. The inverter + battery pair is framed precisely at the study.
* Valeurs indicatives selon la gamme et la configuration. Les performances et garanties exactes dépendent du modèle, du vitrage et des dimensions — confirmées lors du métré.
A poorly sized autonomy system disappoints the day you need it. Our teams calculate the uses to hold, size the battery bank, install and configure the Sunny Island according to the manufacturer's rules, then handle warranty and after-sales directly.
Off-grid and backup answer specific needs. Depending on your autonomy objective and your installation, the approach varies. Compare, then we decide at the study.
An overview of the SMA ecosystem: inverters, battery and monitoring, to place the Sunny Island and its autonomy role.
See the SMA range → to combineThe SMA home battery, an indispensable building block of a Sunny Island system. Without storage, no autonomy.
See Home Storage → vs Sunny IslandFor backup, a hybrid inverter with a backup function may be enough, without a dedicated Sunny Island. A logic to compare against the need.
See the hybrid inverter → vs Sunny IslandFor a classic grid-connected installation without autonomy, the Sunny Boy is enough. The Sunny Island answers a specific need for autonomy.
See the Sunny Boy → by useBefore autonomy, storage: understand the residential battery to place the role of the Sunny Island.
All about home batteries → overviewPointers on the complete photovoltaic installation, to frame an autonomy project fitted with a Sunny Island.
See solar panels →Not everyone needs autonomy, but some projects demand it: an off-grid site not connected to the grid, or a home in an area prone to outages. The Sunny Island answers both cases: it's a battery inverter able to build and maintain a standalone grid.
In backup mode, it switches to the battery as soon as the grid goes down, keeping the essential circuits powered. In off-grid mode, it builds a complete grid from the panels and the storage, with no connection at all. In both cases, the battery sizing is central.
"Autonomy isn't just about an inverter: it's the battery, properly sized, that keeps the home running the day the grid fails.
This is where our role as an installer matters particularly. A poorly sized autonomy system disappoints the day you need it. We define with you the uses to hold, size the battery bank, configure the modes and test the switchover. You keep a single point of contact for warranty and after-sales.
Zero outage for your essential circuits. In backup mode, the Sunny Island switches to the battery as soon as the grid goes down — the actual autonomy depends on the installed capacity and the uses to maintain.
On the budget side, a Sunny Island system is costed mainly on the battery capacity needed for the targeted autonomy — that's the main item. To frame an autonomy or backup project, start from our solar panel pricing page, then ask for a case-by-case quote.
The price depends mainly on the battery capacity needed for the targeted autonomy — that's the main item, not the inverter alone. Here are starting ranges for an SMA system installed by our teams.
See solar panel prices →* Indicative ranges, excluding specific configuration and panels. Precise, costed estimate during your free quote.
It's a battery inverter for off-grid and backup. It powers your home from a battery on an off-grid site, or switches to the storage during a grid outage to keep the essential circuits running.
In off-grid, the system builds a complete standalone grid with no connection at all — for an off-grid site. In backup, the installation stays connected but switches to the battery during an outage. The Sunny Island handles both modes.
Yes. The Sunny Island is a battery inverter: without storage, no autonomy. The battery capacity is sized according to the uses to hold and the targeted duration of autonomy, framed at the study.
In backup mode, yes: it switches to the battery as soon as the grid goes down, keeping the essential circuits powered. The actual autonomy depends on the installed capacity and the uses you want to maintain.
For simple backup, a hybrid inverter with a backup function can sometimes be enough, without a dedicated Sunny Island. For genuine off-grid or extensive autonomy, the Sunny Island remains the right solution. We decide according to your need.
Expect from around €1,800 for the battery inverter alone, and from ~€5,000 for an installed backup system with battery. A complete off-grid is costed on quote depending on the targeted autonomy. Subsidies and 6% VAT are then deducted.
Free on-site survey, recommended range, grants calculated, a single point of contact. Describe your project in under a minute.