Solar energy has become one of the most popular home upgrades in Cairns. This is due to our abundant sunshine. Rising electricity costs also contribute to its popularity. Once your solar panels are installed, you start wondering whether adding a battery is worth it. The short answer? It depends on your energy use and lifestyle. For many Cairns homes, a battery can be a smart long-term investment.
Why a Battery Matters
A solar battery stores the extra power your panels generate during the day. This allows you to use the stored energy later at night when your family needs it most. Instead of selling excess energy back to the grid for a small feed-in tariff (now around 8.66¢ per kWh in regional Queensland), you can store that power and avoid paying 30–35¢ per kWh during evening peak hours.
It’s also a great safety net. During tropical storms or blackouts, certain systems can keep your essential circuits running. These circuits include lights, fridge, or Wi-Fi. They continue functioning until grid power returns. That makes solar batteries especially practical for Cairns households that value energy independence and reliability.
When Adding a Battery Makes Sense
Adding a battery is particularly useful if you:
- Use most of your electricity after sunset — for example, for air conditioning, cooking, or watching TV.
- Have a solar system that often exports a lot of excess energy to the grid.
- Want backup power during outages.
- Are planning to buy an electric vehicle and prefer charging it at home overnight.
If your family’s energy use continues well into the evening, a battery can maximize your solar investment. In short, a battery helps improve energy usage.
How Big Should the Battery Be?
Battery sizing is all about your evening consumption. Start by checking your electricity bill — it shows your average daily usage. Estimate how much of that happens after sunset.
| Night-time Use | Suggested Battery Size |
|---|---|
| 6–8 kWh | 7 kWh battery |
| 10–12 kWh | 10–13 kWh battery |
| 15 kWh+ | 13–15 kWh+ battery |
A typical family in Cairns uses 25 kWh per day. About half of this usage is at night. They would gain from a 10–13.5 kWh battery paired with a 6.6 kW solar system. With Cairns averaging around 4.5 to 5.5 hours of sunshine daily, this setup easily produces enough energy to charge the battery and power the home.
Backup Power Reality
Not all battery systems automatically offer backup during a power outage. To guarantee your system does, you’ll need:
- A hybrid or backup-capable inverter,
- Proper landing configuration, and
- A dedicated essential circuits line (for selected appliances).
Ask your installer to explain what will and won’t stay powered during blackouts. A well-planned setup can keep your essentials running — even when the rest of the street goes dark.
