Australian Design Solar • Home battery guide
How Much Does a 20kWh Solar Battery Cost in Australia?
A 20kWh battery gives you more room to store daytime solar for evening use. But the right purchase depends on your installed price, available solar surplus and how much electricity your household actually uses after sunset.
Updated 8 September 2026 • Prices in Australian dollars
20kWh solar battery price: the quick answer
Australian Design Solar advertises the Anker SOLIX X1 20kWh package from $11,999 installed*. This is a starting offer for a particular configuration, rather than an Australia-wide average. Your final 20kWh battery installation cost depends on the inverter, backup equipment, electrical work, location and any eligible incentives included in the quote.
| Battery installation | Price guide | What to confirm |
|---|---|---|
| Anker SOLIX X1 20kWh | From $11,999 installed* | Exact equipment, usable capacity, inverter, installation scope and rebate treatment. |
| Other batteries around 20kWh | Individual quotation | Compare actual usable storage and output, rather than the package name alone. |
| Battery with selected-circuit backup | Property-specific quotation | Backup hardware, circuit selection and switchboard work. |
| Whole-home or three-phase backup | Detailed system design required | Supported phases, simultaneous loads and additional electrical equipment. |
*Published starting offer checked on 8 September 2026; subject to confirmation, availability and property assessment. Ask for the total payable price including GST, the gross price before incentives, each applicable discount, and all inclusions and exclusions. Do not subtract a rebate again if it is already included. Solar panels, inverter replacement, backup equipment, switchboard upgrades and additional cabling are included only where stated in your written quote.
Get a 20kWh battery quote for your property
Tell us your postcode and contact details. If available, have a recent electricity bill, your existing solar size and inverter model ready so we can discuss a suitable configuration.
Prefer a separate enquiry page? Request a solar and battery quote.
20kWh capacity and 20kW power are different
kWh measures stored energy; kW measures power delivered at a particular moment. A battery described as 20kWh does not automatically provide 20kW of output.
Compare nominal capacity, usable capacity and continuous output separately. The energy available to your appliances also depends on the reserve setting, conversion losses and battery condition.
For example, a battery may have enough stored energy for several hours of use but still be unable to start every large appliance together. Its inverter and backup output set those limits.
What changes the installed cost?
Two quotes labelled “20kWh battery” can cover very different work. Compare an itemised installed scope before deciding which offers better value.
Inverter and connection method
Check whether your current inverter supports the proposed battery. Ask the installer to explain whether the design retains the existing solar inverter, replaces it or adds a separate battery inverter.
Backup requirements
Specify the circuits you want available during an outage. A fridge, lights and internet require a different design from ducted air conditioning, cooking appliances and EV charging together.
Switchboard and battery location
Include photos of your switchboard and proposed installation area with your enquiry. Cable distance, access, equipment positioning and required electrical alterations affect the work quoted.
Equipment and support
Request model numbers, warranty documents and monitoring details. Check who handles a fault, whether labour and freight are covered, and any throughput or operating conditions in the warranty.
Can a 20kWh battery receive a federal discount?
Eligible installations may receive support through the Australian Government’s Cheaper Home Batteries Program. The benefit is calculated through small-scale technology certificates (STCs); it is not a fixed cash rebate for every advertised 20kWh package.
From 1 May 2026, the STC factor applies at 100% for the first 14kWh of usable capacity, 60% for capacity above 14kWh up to 28kWh, and 15% for capacity above 28kWh up to 50kWh.
The dollar benefit depends on the installation date, certificate value, eligible equipment and program conditions. Ask for an eligibility check and an itemised discount before accepting a quote. State incentives and virtual power plant offers require separate checks.
Rebate information reflects program settings checked on 8 September 2026. Ask our team to confirm the eligibility and discount applicable to your installation.
Is 20kWh the right battery size for your home?
Start with electricity used between late afternoon and the following morning, then compare it with your daytime solar surplus. Your total quarterly bill alone cannot tell you how much storage you need.
Worth assessing when
- You regularly export substantial solar energy during the day.
- Your evening and overnight consumption can use a larger stored charge.
- You want to reserve energy for selected backup circuits.
- You expect household demand to grow and can explain when that demand will occur.
Consider a smaller battery when
- Your overnight consumption is relatively low.
- Most electricity is already used while solar is generating.
- There is little surplus solar available to charge extra capacity.
- A larger unit would remain partly unused for much of the year.
An EV or swimming pool does not automatically justify 20kWh. If charging or pumping can happen during solar hours, direct solar use may reduce the storage you need.
Which solar system can charge a 20kWh battery?
There is no single required panel size. Charging depends on generation left over after daytime consumption, seasonal conditions and the battery’s charge limits.
| Solar system | What to assess with 20kWh storage |
|---|---|
| 6.6kW solar system | Check actual exports carefully; daytime household use can leave limited charging energy. |
| 10kW solar system | Review winter surplus and overnight demand before choosing capacity. |
| 13kW solar system | Compare interval data with the proposed battery’s charge and discharge limits. |
| 20kW solar system | Assess site loads, connection conditions and whether 20kWh meets the intended storage goal. |
| 30kW solar system / 50kW solar system | Use a business load assessment; substantial daytime demand can absorb most generation. |
Compare battery options around 20kWh
Ask for like-for-like proposals based on usable storage, output and installed scope. Modular configurations do not always land on exactly 20kWh, so avoid assuming every brand offers an identical capacity.
Explore the range
Start with the Anker SOLIX X1 price reference above, then compare the following guides:
- Sungrow solar battery options
- Alpha ESS home batteries
- SAJ solar battery pricing
- Sigenergy battery pricing in Canberra
- Fox ESS battery prices
The best fit is the configuration that meets your household’s requirements at a clearly documented total cost.
How long can a 20kWh battery run a house?
Runtime equals energy available to the loads divided by their average power demand. The examples below assume 18kWh reaches the appliances after reserves and losses. This is an illustration, not a specification for any particular battery.
| Average connected load | Illustrative runtime |
|---|---|
| 0.5kW | 36 hours |
| 1kW | 18 hours |
| 2kW | 9 hours |
| 3kW | 6 hours |
Real appliances cycle on and off. Starting loads, battery charge level and inverter limits also matter. During a blackout, only circuits supported by the installed backup arrangement will operate. Confirm whether solar can recharge the battery during an outage.
How much could a 20kWh battery save?
A useful estimate compares avoided electricity purchases with the export income you give up to charge the battery. Using the full advertised capacity every day is not a reliable assumption.
Worked example — hypothetical tariffs
- Solar electricity sent into the battery: 15kWh per day.
- Assumed round-trip efficiency: 90%, delivering 13.5kWh.
- Avoided import rate: $0.35/kWh.
- Foregone feed-in tariff: $0.05/kWh.
Daily energy saving = (13.5 × $0.35) − (15 × $0.05) = $3.975.
If this happened every day, the annual saving would be approximately $1,451. At a hypothetical net installed cost of $12,000, simple payback would be about 8.3 years.
This is a calculation example, not a savings forecast or current tariff offer. It excludes finance costs, degradation, maintenance, changing tariffs and variable seasonal charging. Fixed daily supply charges generally remain. Use your own interval consumption and export data for a property-specific estimate.
Keeping more energy in reserve for outages can reduce the amount available for daily bill savings. Decide how much value you place on backup when comparing the economics.
What should your battery quote include?
- Exact equipment: battery and inverter models, module count and usable capacity.
- Performance: continuous power, backup output and supported circuits or phases.
- Installed scope: cabling, switchboard alterations, commissioning and exclusions.
- Total payable: GST, incentive assumptions, optional extras and payment terms.
- Aftercare: warranty conditions, monitoring access and the support contact.
When you enquire with Australian Design Solar, share whether the priority is lower evening imports, outage support or a new solar-and-battery installation. Include your postcode so installation availability and local requirements can be checked.
Frequently asked questions
How much does a 20kWh solar battery cost in Australia?
Australian Design Solar advertises an Anker SOLIX X1 20kWh package from $11,999 installed, subject to confirmation and property assessment. Other configurations require individual quotes. Confirm inverter, backup, GST and incentive inclusions before comparing prices.
Is a 20kW battery the same as a 20kWh battery?
No. A 20kWh rating describes stored energy, while 20kW describes power. Compare the battery’s usable capacity and continuous power output separately.
Can I add a 20kWh battery to existing solar?
A retrofit may be possible. The installer needs to assess your inverter, switchboard, connection arrangement and proposed battery location to specify a compatible design.
Will a 20kWh battery power my whole home in a blackout?
Not automatically. Backup requires a suitable system configuration. The circuits and appliances that can operate depend on backup hardware, phase support, output limits and the available charge.
Is a 20kWh battery better than a 10kWh battery?
Only if you can use the additional capacity or need a larger backup reserve. A smaller battery may offer better value when charging surplus or overnight demand is limited.
Can a 20kWh battery charge an electric vehicle?
A compatible system can supply energy to an EV charger within its output limits, but that leaves less energy for the home. Compare overnight battery charging of the EV with charging directly from daytime solar.
Can I expand the battery later?
Some systems permit expansion, subject to model limits, compatible modules and manufacturer conditions. Ask about future installation costs and eligibility rules before relying on later expansion.
Does the starting price include the government discount?
Confirm this in your written quotation. Advertised offers can use different incentive assumptions. Request the price before incentives, the discount applied and the final amount payable so a rebate is not counted twice.
Find the right battery size for your home
Compare the price, usable storage and backup configuration before you commit. Ask Australian Design Solar for a proposal based on your property and electricity use.
Pricing and quote information
Pricing and program information checked on 8 September 2026. Examples on this page are explanatory calculations rather than performance guarantees. Review our Anker SOLIX X1 20kWh price guide or request a personalised battery quote to confirm current equipment, installation inclusions and pricing for your property.