Pro Calculator

Solar & Battery ROI Calculator 2026

Estimate your return on investment for rooftop solar and battery in Australia, with state-specific feed-in tariffs and 2026 rebates.

Step 1 — Your Profile

Daytime FiT

c/kWh

Evening FiT

c/kWh

Step 2 — System Details

kW
$/kWh
$
STC estimate: ~$1,661 rebate (6.6 kW × 6.8 × $37). Your installer should quote the net price.

Step 3 — Battery (Optional)

Configure your system and press Calculate ROI.

How It Works

This calculator estimates the financial return of adding a home battery to your existing solar system. It models how much solar energy you currently export (at low feed-in rates) versus how much a battery could store for evening use (at full retail electricity rates).

The key metric is the price difference between your feed-in tariff (typically 3-10c/kWh) and your electricity rate (25-35c/kWh). A battery captures this spread by storing cheap solar energy for later use instead of exporting it.

The calculator accounts for battery cost (after any state rebates), degradation over time, and your self-consumption patterns to give you an accurate payback period and 25-year savings projection.

Frequently Asked Questions

How long does a solar battery take to pay for itself in Australia?
Typical payback periods for home batteries in Australia range from 7-12 years, depending on your electricity rate, feed-in tariff, battery size and daily energy usage patterns. Government rebates in some states can reduce this significantly.

What size battery do I need for my solar system?
A 10 kWh battery suits most Australian households with a 6.6 kW solar system. It stores enough to cover evening usage (5-8 kWh). Larger households or those wanting backup power should consider 13-15 kWh systems.

Are there battery rebates available in Australia?
Several states offer battery rebates: Victoria's Solar Homes Program, South Australia's Home Battery Scheme, and the ACT's battery incentives. Federal STCs apply to solar panels but not batteries. Check your state government website for current programs.

How long do solar batteries last?
Most home batteries are warranted for 10 years or a set number of cycles (typically 6,000-10,000). Premium brands like Tesla Powerwall and BYD offer warranties of 10-15 years. Expect 70-80% capacity remaining at end of warranty.

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Last updated: April 2026

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