Punch in the usage from your last power bill. Nothing stored, no sign-up, no sales call.
Your usage
Evenings, overnight and early morning. For many working households 60–75% is a fair starting point.
How much do you want covered?
Recommended solar array
2.6 kW
6 × 440 W panels
Across the seasons
Sizing uses a Bundaberg annual average of 5.2 peak sun hours. Panels make less mid-winter and more mid-summer, so one yearly number overstates June.
Mid-winter this array is about 1.9 kWh/day short of your targets, so expect some grid power. Sizing up, or accepting lower winter coverage, are both normal. Worth talking through on site.
You average 10 kWh a day, with about 6.5 kWh used after dark. The array covers your daytime use and makes extra to recharge the battery, losses included. You set it to cover 100% of total usage. That is a target, not a guarantee.
Want this checked properly?
These are planning numbers. A real quote uses your meter data, your roof and your switchboard.
Planning estimate only. Final sizing must consider meter interval data, roof orientation, shading, export limits, tariffs, inverter compatibility, backup loads and an on-site assessment. A battery can hold enough kWh for the night and still lack the kW to run several big appliances at once. Fennway Electrical — Electrical Contractor Licence 1506444.
How it reads your bill
Total kWh on the bill, divided by the billing days. That’s your daily usage.
The battery covers the night. The panels cover the day and refill the battery.
Panels come in whole units, so we round up. Never down.
The honest bit
A Bundaberg roof makes about 20% less power in mid-winter than the yearly average. Most calculators hide that. Ours checks winter and tells you straight if the system falls short.
Adding a battery? The federal rebate takes around $250 off per usable kilowatt-hour. What the battery rebate is actually worth in 2026.
Want the real number?
The calculator estimates. A site visit and one fixed price is the answer. No obligation.
