The question we get asked most on the Northern Beaches is simple: "If the power goes out, will my solar keep my house running?" The honest answer is no — not unless your battery is wired for backup, and that wiring usually adds $1,500 to $3,000 to the job.

A lot of homeowners assume a battery automatically means blackout protection. It doesn't. Here's how it actually works, what it costs, and where we see quotes quietly leave the backup out.

Why solar alone shuts down in a blackout

By law, a grid-connected solar inverter has to shut off the moment the grid goes down. It's called anti-islanding, and it protects the linesmen working on the network. So even on a sunny day with panels covered in light, a standard solar-only system gives you nothing during an Ausgrid or Endeavour outage.

Adding a battery doesn't change that on its own. A battery installed for self-consumption only — charging during the day, discharging at night to cut your bill — still drops out when the grid fails, unless it's been set up with a dedicated backup circuit.

What "backup" actually means on a quote

Real backup needs a hybrid inverter or battery system that can island — disconnect from the grid and keep running off the battery and solar. That requires a changeover device (an automatic transfer switch or a built-in gateway) and a separate backup sub-board.

Here's the part most homeowners miss: backup is almost never whole-home. The battery can only supply so much power at once — typically 3.3kW to 5kW continuous on common units. That won't run ducted air-con, an electric oven and an instantaneous hot water system together.

So we nominate "essential loads": lights, power points, the fridge, the internet, maybe one split-system. During a quote visit at a place in Frenchs Forest, we'll walk the switchboard with you and decide which circuits move onto the backup board. That choice matters more than the battery brand.

What it costs in Sydney and Newcastle

A typical 10–13kWh battery with a hybrid inverter, fully installed, runs roughly $9,000 to $15,000 in 2024–25. The backup wiring — transfer switch, sub-board, extra labour — sits on top of that, usually $1,500 to $3,000 depending on how your switchboard is laid out.

The federal STC rebate applies to the solar panels, not the battery — so a new solar-plus-battery install still gets that discount up front. From 1 July 2024 there's also a NSW battery incentive that knocks a few thousand dollars off an eligible battery, with an extra payment if you connect it to a Virtual Power Plant later.

Feed-in tariffs have fallen hard — most retailers now pay 4–7c/kWh for exported solar. That's the real reason batteries stack up: storing your own power and using it at night is worth far more than exporting it for loose change.

The switchboard and metering gotchas

Older homes around Dee Why and Mona Vale often have a switchboard with no spare space and no main switch suitable for a backup setup. Fitting a battery there usually means a switchboard upgrade — another $800 to $2,000 we'd rather flag on the quote than spring on you mid-install.

The other common trap is metering. Some battery and VPP setups need a smart meter reconfiguration or replacement, which is the retailer's job, not ours — and it can take weeks. We line that up early so your system isn't sitting half-commissioned waiting on a meter appointment.

A mistake we see from cheaper jobs: the battery gets installed for self-consumption only, the customer thinks they have blackout protection, then a storm rolls through Charlestown and nothing comes on. Always ask, in writing, whether your quote includes a backup circuit.

How much backup you really get

A 10kWh battery running essential loads — fridge, lights, Wi-Fi and a few power points — will comfortably get most homes through an overnight outage, often 8 to 12 hours. If the sun comes up and your panels are working, the battery recharges and can keep that going for days.

That's the genuine advantage of solar plus battery backup over a portable generator: it's silent, automatic, and recharges itself. The trade-off is the power ceiling — heavy appliances stay off until the grid returns.

Get a straight answer for your home

Every backup setup comes down to your switchboard, your roof and which circuits you can't live without. We'll come out, check the board, work out your essential loads and give you a fixed quote that spells out exactly what's backed up and what isn't. Book a free on-site assessment with Impressive Electrical & Solar and we'll map it out for your place.