Australia · Planning tools

Solar Battery Payback Calculator

Estimate whether a battery could reduce your electricity bill enough to recover its cost. Compare the same household with and without storage, including the value of solar energy you would otherwise export.

Your details

Your scenario

Solar-only charging, no grid charging or battery exports. Chronological dispatch respects usable capacity, kW and round-trip efficiency; each year begins empty. Sample-day mode repeats the declared 24-hour profile and is an assumption scenario, not measured annual dispatch. One annual profile repeats with capacity degradation; no tariff escalation. Imported interval data stays in this browser.

Profile basis Usable battery capacity (kWh) Charge / discharge power (kW) Round-trip efficiency (%) Annual capacity degradation (%) Installed cost (AUD) Confirmed rebate / discount not already in price (AUD) Annual ongoing fees (AUD) Projection years Replacement year (0 = none) Replacement cost (AUD) Annual discount rate (%) Tariffs, profile basis, installed price and rebate checked

Interval CSV: hours, load kWh, solar kWh, import cents/kWh, export cents/kWh

Paste a complete chronological 24-hour sample or full year. Five numeric columns; optional header. Load example inserts a declared sample day. Hourly or half-hourly rows only. Prices must already match each interval’s tariff window.

Import local CSV (maximum 3 MB)

Entries stay in this browser. Examples use illustrative confirmations; replace them with your own checked details.

How to use this tool

Enter solar generation and household use, preferably by time interval.
Add battery specifications, tariffs and confirmed installed cost.
Compare annual savings and payback under alternative assumptions.

How the result is calculated

The model tracks energy used, stored, imported and exported. Battery losses and foregone feed-in credits reduce the value of avoided grid purchases.

Worked example

At a 30-cent import rate, avoiding 5 kWh saves $1.50 before accounting for charging losses and the export credits given up. Those deductions are needed for a realistic comparison.

What this result does not cover

Results depend strongly on usage timing and tariffs. This is not an installation design, quote or guarantee of savings.

Questions people ask

Is every stored solar kWh free?

No. You may give up a feed-in credit and lose energy in storage.

Can annual usage alone predict exact savings?

No. Timing matters; interval data improves the estimate.

What if savings are zero or negative?

There is no positive simple payback under that scenario.

Supported scope and official sources

Source snapshot: 22 October 2026. Independent specialist review is pending. Calculations do not confirm eligibility or replace official decisions.

Privacy · Corrections