Storm and cyclone season brings power outages to Darwin and the Top End. When the grid drops out, a solar system on its own switches off for safety reasons, which surprises many homeowners. A battery with backup is what keeps the lights, fridge and fans running. The real question is how much of your home it can power, and for how long.
Solar alone does not keep the power on
A standard grid-connected solar system shuts down when the grid goes off, even in full sun. This protects line workers repairing the network. To keep running during an outage, your system needs a battery and an inverter set up for backup, wired so your home can disconnect from the grid safely.
Whole-home backup versus essential circuits
Some backup systems only supply a few chosen circuits, such as lights and the fridge. We normally set up whole-home backup, where the battery can supply every circuit in the house. That is the most convenient option, but it also means a heavy load such as an air conditioner can drain the battery faster, so it pays to size the system around how you want to live during an outage.
How long will a battery last?
Run time depends on two things: how much energy the battery stores, measured in kilowatt-hours (kWh), and how much power your home is using at the time, measured in kilowatts (kW). As a simple example, a 12 kWh battery supplying a steady 2 kW load would last roughly six hours, before allowing for losses. Light use, such as fans, lights, the fridge and a phone charger, uses far less than that, so the battery lasts much longer. Running one or more air conditioners uses a lot more.
Home batteries generally range from about 12 kWh to 60 kWh or more. If your solar system is set up for it, the panels can also recharge the battery during the day while the grid is still down, which stretches your backup time. We will confirm how this works for your system.
Questions to ask before you choose
- Will the system provide backup, and does it cover every circuit or only some?
- How long will it run my air conditioning, hot water and fridge together?
- Can the solar recharge the battery during an outage?
- Does the system switch over automatically, and how quickly?
- Can the battery be expanded later if my needs change?
Rebates and next steps
The federal Cheaper Home Batteries Program funds around a 30% discount on eligible batteries, built into your quote. The certificates have been tiered by battery size since 1 May 2026, and the NT Government’s battery scheme has closed. The discount also steps down every six months, with the next reduction scheduled for 1 January 2027. Our guide to solar energy grants and programs explains how it works, and is a home battery worth it in Darwin covers whether the numbers stack up for you.
Florance Energy Solutions designs and installs Fronius and BYD battery systems with whole-home backup. See our solar battery storage and backup power service, or contact us for a free on-site consultation. For related reading, see the battery maintenance tips for Northern Territory homes on the Florance Electrical blog.
