Off-Grid Solar, a 16 kWh Sigenergy Battery and an Auto-Start Generator in the Mullumbimby Hinterland: Case Study

A home in the Mullumbimby hinterland taken fully off the grid: 13.3 kW of solar on tilt frames, a 16.12 kWh Sigenergy battery with a Sigenergy Gateway, and an 8.5 kW diesel generator that starts automatically.

Our own in-house electricians designed and installed it in two stages between May and July 2026, finishing with the main switchboard disconnected from the network.

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The job

A hinterland home on a rural block. The household started with solar and a battery while still on the grid, then decided to go fully off-grid. Because the first stage was designed with a Gateway that already had a generator input, the second stage built on it instead of starting again.

What we installed

Stage one (May 2026), still on the grid:

• Solar: 6.65 kW
• Battery: an 8 kWh Sigenergy battery module (8.06 kWh) with a Sigenergy hybrid inverter
• Gateway: a Sigenergy Gateway with generator input, for backup and on/off-grid switching
• Safety: Type A RCBO protection on every backed-up circuit
• Load control: a Shelly smart load controller, so big loads can run on surplus solar

Stage two (June to July 2026), off the grid:

• More solar: another 6.65 kW of panels (14 Trina Vertex S+ 475 W), 13.3 kW in total
• Tilt frames: the new panels went on tilt frames, and the existing panels were re-installed on tilt frames too
• Battery doubled: a second module, for a 16.12 kWh Sigenergy SigenStor (15.6 kWh usable) with a 10 kW hybrid inverter
• Generator: an 8.5 kW (10 kVA) diesel generator, silent running, with two-wire auto start through the Gateway
• Off the grid: the main switchboard and meter box reconfigured to disconnect from the network, with the generator backing up the submains

How it works day to day

The solar runs the home during the day and charges the battery. The battery carries the home through the night. After a long run of cloudy, wet days, when the battery runs low, the Gateway starts the generator on its own to keep the power on and top the battery up, then the solar takes over again when the sun returns.

Tilting the panels gives a better angle to the winter sun, when an off-grid home needs every bit of solar it can get. Read how off-grid solar works.

How we run an off-grid job

1. Free energy assessment from your power bills, or a list of what you run if you’re already off-grid.

2. Custom design for winter and wet spells: panels, battery and generator sized together. Solar STCs come off at point of sale and we handle the paperwork.

3. Face-to-face site visit before install day: battery position, switchboard, panel and frame positions, and where the generator goes.

4. Install by our own electricians, no subcontractors, then monitoring set-up and a sign-off call.

Warranties

10-year battery, 10-year inverter replacement, 25-year panel performance and our 25-year workmanship warranty on our installation work. Equipment is covered by the manufacturer warranties.

Questions we get asked

Can you take a grid-connected home off the grid?

Yes. On this job we reconfigured the main switchboard and meter box so the home runs from its own solar, battery and generator, with no network connection. Before you go off-grid, read off-grid approvals: what to check in NSW and off-grid or grid-connected with a battery.

What does the generator do in an off-grid system?

It is the back-up for long runs of cloud and rain. Here an 8.5 kW (10 kVA) silent-running diesel generator is wired to the Sigenergy Gateway with a two-wire auto start, so it starts on its own when it is needed instead of someone having to go out and start it.

Can an off-grid system be added to later?

Yes. This one was built in two stages: first solar, a battery and a generator-ready Gateway, then double the solar, double the battery and the generator when the household went fully off-grid. Sigenergy batteries are modular, so more modules can go on later.

Do off-grid systems still get solar rebates?

Solar STCs still apply off-grid, and on this job they came off the price at point of sale on both stages. See your rebates.

How do you size an off-grid system?

From the household’s real power use, then for winter sun and a long wet spell, not a summer day. That sets the panels, the battery and the generator. See off-grid battery days of autonomy.

Thinking about off-grid solar in the hinterland?

We’re based near Mullumbimby and install off-grid systems across the hinterland and the wider Northern Rivers. See our off-grid solar page and Mullumbimby solar and battery installers page, work out what size battery you need, or compare Sigenergy, GoodWe and Sungrow, Solax and Tesla.

Or call 0483 903 020.

Find us on Google Maps to read our reviews, or follow our installs on Facebook and Instagram.

More from Sun Connect Solar: your rebates; battery rebate calculator; customer reviews; FAQ; recent installs: 96.72 kWh commercial Sigenergy battery, Murwillumbah area farm · 22.8 kW solar, 40 kWh Sigenergy battery and DC EV charger, Huonbrook · 12 kW AIKO solar and Sigenergy battery, Wilsons Creek · Solar and a 24 kWh Sigenergy battery, Mullumbimby area · 24 kWh Sigenergy battery added to existing solar, Lismore · all recent installs.