Solar battery cost by size: 5, 10 or 13.5 kWh?
What a 6 kW solar system costs in Australia with no battery or a 5, 10 or 13.5 kWh battery, how the federal battery discount works and how to size storage.
A 6 kW rooftop solar system with a 5 kWh battery typically costs $8,900 installed in Australia, after STCs on the solar and including GST. A 10 kWh battery brings it to about $10,300, and a 13.5 kWh battery to around $11,300. The same panels with no battery come in at about $7,500. On top of that, the federal Cheaper Home Batteries Program has cut the price of home batteries since July 2025, through a discount that reduces every six months until 2030.
The same system, four battery sizes
Every row below is the same 6 kW system on a pitched tiled roof - panels, mounting, inverter, cabling, monitoring, scaffolding and commissioning - with only the battery changed. Figures include 10% GST.
| Material | Typical | Usual range | Lifespan |
|---|---|---|---|
| No battery | $7,500 | $5,850 – $9,750 | – |
| 5 kWh battery | $8,900 | $6,950 – $11,600 | – |
| 10 kWh battery | $10,300 | $8,050 – $13,400 | – |
| 13.5 kWh battery | $11,300 | $8,800 – $14,700 | – |
Because everything else stays the same, the gap between two rows is what the extra storage costs. Change the system size and see every line in our Solar panels.
What each size suits
No battery
Panels only ($7,500) are the cheapest way into solar and pay back fastest if someone is home during the day to use the power as it is generated. The rest is exported at the feed-in tariff, which is usually far less than you pay for grid power.
5 kWh
A 5 kWh battery ($8,900) covers a typical small household's evening: lights, cooking, TV and the fridge until bedtime. It suits couples and small families out during the day.
10 kWh
A 10 kWh battery ($10,300) suits bigger families, or homes running air conditioning into the evening in summer. It also leaves room to join a virtual power plant, where the battery is partly managed by a retailer in return for credits.
13.5 kWh
A 13.5 kWh battery ($11,300) makes sense with an electric car, a pool pump, ducted air conditioning or very high evening use. With a 6 kW array it will not fill every day in winter, so check that your usage really needs it, or consider more panels.
Size to your evening use, not your panels
A battery only saves money on the power that actually cycles through it. An oversized battery sits partly empty much of the year and takes much longer to pay back.
- Check your bills or your retailer's usage data for how much you use from late afternoon until the next morning.
- Aim to cover most of a typical evening, not the worst day of the year.
- Add capacity for a specific reason: an electric car, evening air conditioning or a virtual power plant you plan to join.
How the battery discount works
The Cheaper Home Batteries Program works through certificates created when an eligible battery is installed. In most cases the installer claims them and takes the value off your price, much as solar installers handle STCs on panels. The discount reduces every six months until 2030, so the same battery attracts less support the later you install it.
In practice:
- Ask for the discount as a separate line on the quote, so you can see the real price of the battery and installation.
- Compare quotes on the price you actually pay, after the discount.
- Get eligibility confirmed in writing before you sign.
- Don't let a step-down date rush you. It is a reason to plan, not to sign a quote you have not compared.
Battery prices are moving quickly while the discount steps down, so check the date on any quote you compare.
State schemes
Some states add support. In WA, the residential battery scheme pays up to $1,300 (Synergy) or $3,800 (Horizon Power) with virtual power plant participation. In Victoria, Solar Homes offers a solar panel rebate of up to $1,400, with a household income cap of $150,000 from 1 July 2026. Check eligibility before you sign, not after installation.
What the price includes
- About 13–14 all-black 450 W panels on aluminium rails
- A hybrid inverter that manages panels and battery, with isolation and surge protection
- Cabling to the switchboard with a dedicated breaker
- Monitoring of generation, battery and household use
- Scaffolding, permanent roof anchor points, connection and commissioning
Not included: a switchboard upgrade, a three-phase supply upgrade, network connection fees, or roof repairs.
We build these prices from the equipment and the hours licensed electricians need at local labour rates, then check them against market prices and real quotes.
Licensing and your quote
Solar and battery installation is electrical work and must be done by licensed tradespeople under state licensing. Quotes to households include 10% GST, and so do our figures.
Ask every installer to quote the same panels with two battery sizes and to state the usable capacity. Then compare each total with typical prices in your state using our "Is my quote fair?" tool: Is my quote fair?. Enter the price you will actually pay, after any discounts.