A quote is financially promising when the battery is sized to the energy you can actually cycle, the final installed price is complete, and degraded savings comfortably recover that price inside the warranty.
What makes an Australian battery quote fair?
Start with the final amount you will pay after federal support and installer discounts. Divide that by usable battery capacity, then check what the price includes. A lower number is not automatically better if the quote omits switchboard work, metering, monitoring, approvals or the backup hardware you expected.
The financial test comes next. Stored solar replaces electricity bought from the grid, but it also gives up the feed-in tariff that exported solar would have earned. The calculator values only the energy your home can realistically charge and use, applies efficiency and degradation, and compares the result with the warranty period.
Compare the same six things on every quote
| Quote line | What a complete quote shows | Warning sign |
|---|---|---|
| Final installed price | The amount payable after incentives and discounts | An allowance or essential work excluded from the total |
| Usable capacity | Energy you can actually cycle—not nominal capacity | Only the larger nominal figure appears |
| Federal support | Estimated STCs and the certificate value credited | A rebate is advertised without showing the maths |
| Inverter and power | Continuous output, phase compatibility and backup limits | Capacity is quoted but power limits are missing |
| Installation scope | Switchboard, metering, approvals, monitoring and backup circuits | The cheapest quote leaves major electrical work open |
| Warranty recovery | Modelled savings repay the price before the warranty ends | Payback relies on unexplained VPP or tariff income |
Use your household—not a generic sales profile
Useful daily storage = the lowest of usable capacity, solar available to charge, and evening demand adjusted for efficiencyExtra capacity above the household’s real charging or discharging limit does not automatically create extra savings.Use exported energy from your electricity or solar-monitoring data where possible. If the quote’s payback uses a different usage profile, ask the installer to reproduce it using your actual exports, evening demand, import tariff and feed-in tariff.
Australian battery quote red flags
- The quote highlights nominal capacity but does not state usable capacity.
- The federal incentive is described as a fixed cash rebate without showing estimated STCs or certificate value.
- The payback assumes VPP income, future tariff arbitrage or electricity-price growth without separating those assumptions.
- Backup is promised without listing the circuits, output limit or additional hardware.
- Switchboard upgrades, metering, approvals or monitoring are excluded or left as allowances.
- The battery is much larger than both your average solar export and after-sunset electricity use.