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Solar & Battery Calculator

Calculate recommended solar panels and battery bank for your Australian off-grid system.

Off-Grid SizingAU Sun Hours

How to use this calculator

Enter average daily electricity use, peak-sun hours, autonomy target and system losses, then calculate a starting panel and battery size for installer review.

Useful real-world examples

  • Exploring a starting solar-system size from daily electricity use.
  • Comparing battery capacities against evening energy demand.

Important detail

Roof orientation, shading, inverter limits, tariffs, weather and battery efficiency all affect real performance.

About the Solar & Battery Calculator

This calculator estimates the solar panel system size and battery storage you need for your home or off-grid setup, based on your daily energy consumption and your location's average peak sun hours. It is designed for Australian conditions and provides a starting point for conversations with solar installers.

How to Use It

  1. Enter your average daily electricity usage in kilowatt-hours (kWh). This is on your electricity bill — divide the total kWh for the quarter by 90 to get a daily figure.
  2. Select your state or territory to apply the correct average peak sun hours.
  3. Indicate whether you want battery storage and what percentage of your usage you want to cover overnight.
  4. Review the recommended system size in kilowatts (kW) and battery capacity in kWh.

Solar in Australia

Australia has some of the world's best solar resources — particularly in Queensland, South Australia, and Western Australia, where peak sun hours regularly exceed 5–6 hours per day. The typical Australian home uses 15–20 kWh per day and suits a 6.6 kW solar system with an optional 10 kWh battery. Federal and state government rebates apply through the Small-scale Technology Certificate (STC) scheme, which reduces upfront installation costs. Feed-in tariffs (FiTs) paid for excess electricity exported to the grid vary by state and retailer — compare your options at Energy Made Easy (energymadeeasy.gov.au).

The typical payback period for a residential solar system in Australia is 3–6 years, depending on system size, your electricity usage pattern, local electricity prices, and whether you receive government rebates. High daytime electricity users (running appliances during the day rather than at night) see the fastest payback. Adding battery storage extends the payback period but increases self-consumption and provides backup power during outages.