Key Takeaways More Australian households are looking at 10kW solar batteries for one simple reason. Power bills keep climbing, and […]
| Quick Answer Adding a Battery to an Existing Solar System typically costs between A$8,000 and A$20,000+ in Australia. This will, of course, depend on the battery size, brand, and installation complexity. |
Electricity prices in Australia are high. For instance, in NSW and Victoria, the average retail electricity rates commonly sit between 30 and 40 cents per kWh, depending on provider and tariff structure. That’s a serious rise compared to a few years ago.
Meanwhile, over 4 million Australian homes already have rooftop solar installed. But here’s the issue. Without a battery, most homes only use about 20–40% of their solar energy directly, exporting the rest back to the grid for low feed-in tariffs (often under 10 cents per kWh).
That gap is why batteries are getting attention, and adding one to an existing system generally costs A$8,000–A$20,000 installed pre-rebate for a 10–13.5kWh system
After federal incentives, this can fall to A$6,000–A$12,000.
The good news is that retrofitting is usually straightforward. Most existing systems use standard string inverters, which makes AC-coupled battery installs relatively simple.
Battery Types for Retrofits
When adding storage to an existing solar system, the type of battery setup matters.
1 AC-Coupled Batteries
These are the most common retrofit choices.
Systems like Tesla Powerwall and Enphase batteries are AC-coupled. This means they connect to your existing system without replacing your inverter.
That keeps installation simpler, and a 13.5kWh AC-coupled battery typically costs between A$11,500 and A$16,000 installed.
They’re often described as “plug-and-play” because they don’t require swapping your original inverter.
For most households with an existing 5–10kW solar system, this is the easiest path.
2 DC-Coupled Batteries
DC-coupled systems such as Sungrow SBR or BYD connect on the DC side of the inverter.
They can be more efficient if paired with a compatible hybrid inverter. But if your current inverter doesn’t support batteries, you may need to replace it.
That can add A$1,000–A$2,000 to the job.
For a 10kWh DC-coupled battery, pricing generally sits between A$8,500 and A$12,500 installed.
Installed Cost Breakdown
| Capacity | Pre-Rebate (AUD) | Federal Rebate (~$336/kWh) | Net Cost Estimate |
| 10kWh | $8,500–$12,500 | ~$3,360 | $5,100–$9,100 |
| 13.5kWh | $11,500–$15,500 | ~$4,500 | $7,000–$11,000 |
| 20kWh | $15,000–$20,000 | ~$6,700 | $8,300–$13,300 |
Installation labour typically costs:
- A$1,000–A$2,500
- Usually completed in 1–2 days
- Metro areas can add 10–20% more
Rebates and Incentives
Under the federal Cheaper Home Batteries Program, households can receive approximately $336 per kWh of usable battery capacity (until May 2026).
That’s roughly:
- ~$3,300 for a 10kWh battery
- ~$4,500 for a 13.5kWh battery
In addition, some states offer extra programs:
- NSW Peak Demand Reduction Scheme – incentives often exceeding A$1,500 depending on the system
- VIC Solar Homes Program – rebates up to A$4,000 (when available)
- Small-scale Technology Certificates (STCs) may add another A$1,000–A$2,000 in benefit
Combined, rebates can reduce upfront costs by 30–40%. Eligibility generally requires:
- Existing solar system
- CEC-approved battery and installer
- Grid-connected property
Factors Affecting Total Cost
Battery pricing isn’t fixed, and several things influence your final quote. These include:
Location
Where you live matters more than people expect.
Labour rates differ across states. Grid rules also vary. A 10kWh battery installation in Sydney can cost around A$1,000 more than in Adelaide. Regional areas may face higher travel and freight charges. Metro areas can add 10–20% depending on demand.
Some states also have additional compliance or metering requirements, which increase labour time.
Brand and Battery Size
Premium batteries such as Tesla typically sit at the higher end of the market. Mid-range and value brands have become more competitive in recent years. Industry reporting shows battery prices have fallen by roughly 40% since 2022, but premium brands still command a higher installed cost.
Capacity also scales pricing directly. A 13.5kWh system will cost thousands more than a 10kWh system and larger 20kWh setups increase both hardware and labour costs.
Inverter Compatibility
This is one that many homeowners miss.
If your existing inverter isn’t battery-compatible, you may need:
- A new hybrid inverter
- Or an AC-coupled battery instead
Replacing an inverter can add A$1,000–A$2,500 depending on size and brand. Older solar systems (10+ years old) are more likely to need upgrades.
Switchboard Upgrades
Sometimes the battery isn’t the issue — the switchboard is.
If your main board doesn’t meet current electrical standards or lacks space, upgrades may be required. That can add anywhere from A$500 to A$2,000.
It’s not common in newer homes, but it does come up.
Backup Configuration
If you want blackout protection, costs increase.
Basic battery installs may only reduce bills. True backup requires:
- A backup gateway or automatic changeover switch
- Rewiring of essential circuits
This can add around A$1,000 to A$2,000, depending on complexity.
Payback and Savings: Is the investment worth it?
On average, an Australian household using 10kWh of stored energy daily will save between A$800 and A$1,500 per year on their power bills.
With a net cost of A$8,000 (after rebates), your payback period is roughly 6 to 8 years. If you join a Virtual Power Plant (VPP), you can shave another year off that by earning “event credits” when the grid is under stress.
Considering most tier-one batteries like Tesla and Sungrow are warrantied for 10 years, you’ll likely see 2–4 years of “pure profit” before the battery’s performance significantly degrades.
When a Battery Doesn’t Make Financial Sense
While batteries are becoming cheaper, they are not necessarily a smart decision for every household.
If you don’t use much electricity in the evening, it’s not worth it.
Batteries are most cost-effective when you have excess solar electricity generated in the day and you use it at night when you are using your electricity at maximum capacity. If you are home in the day and you are using most of your electricity, you might not get much out of a battery.
In addition, in some states, particularly Queensland and NSW, older feed-in tariffs pay rates of over 20 cents per kilowatt hour. In these situations, feeding your electricity into the grid might be more cost-effective than using a battery.
Furthermore, solar systems under 5kW capacity will not be able to charge batteries to capacity, particularly in winter. An underutilised battery will increase payback periods significantly.
A battery will be most cost-effective if you have:
- Solar systems of 5kW+ capacity and above
- Time of use tariffs with high evening peak rates
- Moderate to high nighttime energy consumption
Final Thoughts
Indeed, the cost of adding a battery to an existing solar system in Australia will vary from A$8,000 to A$20,000 before any incentives are applied. For most households, this will put them in the range of A$6,000 to A$12,000 after receiving rebates.
Clearly, the increasing prices in the retail electricity market, lower feed-in tariffs and federal incentives have made batteries more attractive than they have been in the past.
Some households are installing batteries to have more control over their household electricity usage. Others are engaging in Virtual Power Plants to gain additional credits.
If your household’s system size, pattern and electricity tariffs are right, a battery will not only reduce your dependence on the grid but will also help you save money.
