Blackout backup planning
Choose what stays on before choosing how much battery to buy.
Backup is a designed operating mode, not a feature created by battery capacity alone. Start with the circuits and loads your household actually needs when the grid drops.
Capacity versus power
kWh tells you how long. kW tells you how much at once.
Stored energy · kWh
Battery capacity supports runtime. A larger number can keep a modest load operating longer, but it does not automatically increase the maximum load the backup output can supply.
Backup output · kW
The inverter EPS output, battery discharge limits and appliance starting currents determine what can run at the same time. Motors, pumps and air conditioners need particular attention.
Define the backup scope
Build from essentials, then test the larger loads.
Essential circuits
Fridge, selected lights, communications and chosen power points form a clear starting scope and make the expected behaviour easier to explain.
Comfort loads
Air conditioning, cooking and water heating may be possible in a larger design, but their continuous and starting demand must fit the backup pathway.
Managed loads
EV charging, pool equipment and other high-demand circuits may need to remain outside backup or operate under a deliberate load-management plan.
Tell us what must stay on.
List your essential circuits and any large loads you want considered. We’ll identify what needs checking at the switchboard and equipment level.
Backup questions
Set expectations before install day.
Will a home battery automatically work in a blackout?
Not necessarily. Blackout operation needs compatible equipment, a defined backup output, switching and selected circuits. A grid-connected battery without the required backup design may shut down with the grid.
Can I run air conditioning during an outage?
Possibly, but the answer depends on the unit, starting current, other simultaneous loads, inverter backup output and battery limits. The circuit and load need to be checked rather than assumed from battery capacity.
How long will a battery last during a blackout?
A rough estimate is usable battery kWh multiplied by system efficiency, divided by average backed-up load in kW. Real runtime changes with state of charge, temperature, appliance cycling and any solar available during the outage.
Can solar recharge the battery while the grid is down?
Some deliberately designed systems can; others cannot keep the existing PV inverter operating off-grid. It depends on coupling, compatible controls, load balance and the commissioned backup architecture.
Related decisions
Continue your research.
Installer comparison
How to choose a solar battery installer in Brisbane
Compare accreditation, equipment, site scope, backup, warranties and after-sales responsibility before signing.
Read the guide →Three-phase design
Three-phase home battery guide for Brisbane
Understand inverter architecture, existing solar, metering, Energex connection pathways and blackout scope.
Read the guide →Warranty and support
Home battery warranty and after-sales support
Separate product, performance and workmanship cover, registration, consumer rights and the fault pathway.
Read the guide →