KEY POINTS
- A solar battery stores excess energy from your solar panels for use in poorer lighting conditions such as nighttime or cloud cover.
- A solar battery may save you money if you’re on a single rate tariff or a varying rate structure, such as a time of use tariff or controlled load tariff — however, this depends on how you use it.
- Whether a solar battery is worth it depends on the tariff type, its payback period or whether having backup storage is a must.
More Australians are adding solar batteries to their rooftop solar systems, allowing them to store electricity generated by their panels for use later or to export back to the grid in exchange for a rebate.
This Canstar Blue guide takes you through the basics, including what a solar battery is, how it works, how much they cost, and whether the savings made are worth the upfront investment.
On this page:
- What is a solar battery?
- How do solar batteries work?
- How can a solar battery save you money?
- How much do solar batteries cost?
- Am I eligible for solar battery rebates?
- What features should I look for in a solar battery?
- How long do solar batteries last?
- What size solar battery do I need?
- How do I install a solar battery?
- Are solar batteries worth it?
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What is a solar battery?
A solar battery stores excess energy generated by solar panels during the day, charging it for use when sunlight conditions are poorer (i.e. nighttime or heavy cloud cover)
How do solar batteries work?
The stored energy in your solar battery works in different situations:
- To power appliances in your home when sunlight exposure is low, reducing your reliance on grid power — if your energy consumption exceeds the amount of energy stored, it’ll be supplemented by the grid.
- Complete or partial backup storage for use in the event of a power outage (only for solar batteries with backup capabilities).
- Depending on your energy consumption and the size of your solar system and battery, it is possible to go off-grid with your solar system, severing your reliance on the grid.
To learn more about the scientific process behind solar battery storage, please visit the following Canstar Blue Guide.
How can a solar battery save you money?
Installing a solar battery can help you reduce your power bill by enabling you to use more of the power generated from your solar system.
Generally, when electricity is produced by a solar system without a solar battery, it is diverted to the energy grid during the day when nobody is home to use it in exchange for a feed-in tariff (FiT) – a small solar rebate on your energy bill, which typically amounts to 5c to 20c per kilowatt hour (kWh).
With the ‘sun tax’ or two-way pricing tariff being rolled out across various states, the dollar savings generated from FiTs are set to dwindle further.
Because the price of grid electricity (typically 20-45c/kWh, depending on your plan and location) already exceeds the standard FiT rate (5-20c/kWh), you would save more from consuming energy stored in a solar battery than from exporting it back to the grid.
Note: the example below assumes that the user’s rooftop solar system produces a total of 10kWh of solar energy per day to be exported or consumed
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| Rebate from a Solar FiT (11c/kWh) | Savings from consuming stored solar energy (30c/kWh) |
|---|---|
| $1.10 per day | $3.00 per day |
If you are on a time of use tariff, you could save even more by storing solar power generated during off-peak hours. During peak hours, when grid electricity is more expensive, you could use your stored excess energy instead of relying on grid power.
Solar Quotes suggests that you could save up to two times more with your solar battery on a time of use tariff over a single rate tariff, where the usage rate for electricity is fixed regardless of the time of day.
Note: The example below assumes that the user owns a Tesla Powerwall 2
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| Tesla Powerwall | Annual savings: Flat rate | Annual savings: Time-of-use |
|---|---|---|
| Best case savings | $1,232 | $2,616 |
| Best case payback | 8.5 years | 4 years |
| More realistic savings | $730 | $1,677 |
| More realistic payback | 14.5 years | 6.4 years |
Source: Solarquotes, June 2025
Customers on a controlled load tariff can also benefit from the varying rate structure by connecting their solar battery to the controlled load. By charging their battery overnight with cheaper, off-peak grid electricity, their controlled loads can remain powered during peak hours without having to pay for pricier grid power.
However, how much you can save is limited by the efficiency of your solar inverter and how much excess solar energy your solar panels can capture and store in your solar battery.
Moreover, the possible savings over time are partially offset by the upfront cost of installing a solar battery.
These two cost-effectively extend a solar battery’s payback period, which is the time it takes to recoup the upfront investment.
To roughly calculate a solar battery’s payback period (of a specific brand, make and model), visit SolarQuotes’ official payback calculator.
How much do solar batteries cost?
A new solar battery will cost around $2,000 to $20,000, depending on the brand, size and make of the model.
The table below features some of Canstar Blue’s best-rated solar batteries across a range of prices and sizes:
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| Model | Brand | Size | Price* (excluding installation costs) |
|---|---|---|---|
| BYD Premium LVS | BYD | 12 kWh (able to add more storage modularly) | $8,000 – $9,000 |
| SunGrow SBR HV | SunGrow | 12.8kWh (able to add more storage modularly) | $9,000 – $10,000 |
| Tesla Powerwall 2 | Tesla | 13.5kWh | $13,000-$15,000* |
Source: Canstar Blue, Best Solar Battery Storage, June 2025
Factors that influence how much a solar battery could cost and its payback period include:
- Capacity: SolarQuotes states that every additional kWh of capacity costs between $1,000 and $1,200.
- Backup Capability: Batteries with full or partial backup functionality are typically more expensive.
- Battery type: The common types of solar batteries are LiFePO4, lithium-ion, flow, nickel-iron and lead-acid — LifePO4 and lithium-ion batteries are generally more expensive.
- Weatherproofing: Ingress protection (IP) rated or weather-resistant batteries typically cost more.
- Warranty: Solar battery warranties typically cover at least 10 years or the lifespan of the battery sold, but some brands offer longer or shorter warranties — extensive warranties may add more to your upfront cost.
- Installation costs: The cost to install a solar battery may incur a separate charge, but some solar panel installers may even offer you a solar and battery system install with no upfront costs.
- Solar financing: Financing a personal battery through personal loans (i.e. green loans) typically comes attached with interest rates and fees, adding onto the long-term cost of paying off your battery.
Am I eligible for solar battery rebates?
Aussies could be eligible for federal or state-run solar rebates and interest-free loans, lowering the cost of purchasing a solar battery and its payback period.
Federal rebates
- Cheaper Home Batteries Program: The Labor Government’s recently announced program, starting July 1, 2025, offers a discount of approximately 30% off the cost of installing residential solar batteries. This can be used on top of state-level rebates.
- Household Energy Upgrades Fund: While this isn’t an explicit rebate, Aussies who want to make their homes more energy-efficient may have access to a list of curated discounted products, including solar batteries.
State-run solar rebates
- NSW solar battery rebate: NSW is currently running a battery rebate scheme — the value of the rebate is contingent on whether or not you purchase an approved solar battery from an accredited seller and the battery’s usable capacity.
- SA solar battery rebate: Adelaide currently offers solar battery rebates of up to 50% (capped at $2,000) of the installed system cost.
- WA solar battery rebate: Starting from July 1 2025, over 100,000 eligible Synergy customers and Horizon energy customers may access up to $5,000 and $7,500 of solar battery rebates respectively.
- NT solar battery rebate: The Home and Business Battery Scheme offers a solar battery rebate of $400 per kWh of usable capacity, up to a maximum value of $12,000 for eligible customers.
- ACT solar battery rebate: The ACT Government is running the Sustainable Household Scheme, which is an interest-free loan scheme for green home upgrades — this includes solar batteries.
- What features should I look for in a solar battery?
What features should I look for in a solar battery?
When picking a solar battery, there are key specifications that households should be mindful of:
- Depth of Discharge (DoD): The ‘depth of discharge’ is a metric that describes how much of the battery’s power (in percentage) can be discharged (i.e. 80%). A high DoD means you can use more of your battery’s stored energy before it needs recharging.
- Storage (kWh): A battery’s storage is measured in kilowatt-hours (kWh). There are two types of storage: nominal and usable. Nominal storage refers to the total amount of electricity that can be held. Usable storage refers to the total amount of electricity that can be used after factoring in the depth of discharge.
- Power (kW): Power is measured in kilowatts (kW) and refers to the maximum amount of electricity that a battery can discharge in any one moment. The more power, the faster the battery will discharge. This is an important feature if your home uses a lot of electricity.
- Cycle: A ‘cycle’ refers to a discharge and recharge of a battery. It is often used as a unit of measurement for battery life. Lifespan: A battery’s lifespan indicates how long it is expected to last before it severely degrades. A longer lifespan means that your battery will last longer and not require replacing early on.
- Backup Capabilities or Emergency Power Supply (ESP): This refers to the battery’s ability to power a household whilst disconnected from the grid during a blackout or power outage. Not all batteries come with this feature, and the ones that do may do so in partial or full capacities.
If you are confused by any of these terms or specifications, you can discuss them with a licensed solar installer during the quotation process.
How long do solar batteries last?
A good quality solar battery generally lasts between five to 15 years or several thousand cycles before it needs replacing.
How long a solar battery would last depends on the following:
- Depth of discharge: A higher DOD stresses the chemical composition of your battery, accelerating your battery’s aging.
- State of Charge (SOC): SOC refers to the percentage of energy stored in relation to your battery’s total usable capacity. Manufacturers will usually specify a minimum SOC to maintain a battery’s health and performance. Constantly exceeding the minimum SOC will lower the lifespan of your battery.
- Frequency of charges/discharges: How frequently your battery is fully charged and discharged will contribute to its degradation over time.
- Battery type: Lithium-ion batteries have a longer lifespan of 10-15 years, while lead-acid batteries last between 5-10 years. Flow batteries, a new form of storage technology that’s more expensive, can generally last between 15-25 years or tens of thousands of cycles.
- Environmental conditions: In hotter climates, the performance and longevity of your solar battery are impacted by extreme temperatures and overheating.
The signs of a degrading solar battery also include:
- Loss in capacity: The battery is still usable at the end of its lifespan; however, it will likely only hold about 60-50% of its original capacity.
- Having to recharge it more frequently: If you need to increase the frequency of your charge cycles to maintain a consistent level of performance.
What size solar battery do I need?
The exact size of the battery needed for a solar system will vary depending on what you hope to achieve with a new solar battery.
- Budget: Your willingness to spend will determine the size, features and limitations of your preferred solar battery make and model, be it the cheapest or the best for your needs.
- How much energy your solar panels generate: The size of your battery is directly influenced by how much energy your solar system is producing. A good rule of thumb is to have at least double what your system is capable of for sufficient storage.
- How much solar energy are you consuming: The volume of excess solar energy you have left after consumption (in kWh) determines the size of your solar battery. To accurately assess your energy usage in real-time, you can install an electricity usage monitor or a solar monitoring system.
- How you plan to use your stored energy: If you wish to power your entire house on solar energy in the evening or go fully off-grid, you’ll need more storage space than the average household.
Solar Plans & Prices
Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on the Ausgrid network in Sydney but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 3900kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information. Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on the Citipower network in Melbourne but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 4000kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information. Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on the Energex network in Brisbane but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 4600kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information. Here are some of the cheapest solar-specific deals from the retailers on our database. These costs are based on SA Power network in Adelaide but prices will vary depending on your circumstances. We show one product per retailer, listed in order of lowest price first. Annual price estimates assume general energy usage of 4000kWh/year for a residential customer on a single rate tariff. Price estimates exclude solar feed-in tariff credits. These are products from referral partners†. Our database may not cover all deals in your area, and please check retailer websites for up to date information.
How do I install a solar battery?
Note: You’ll need to have a compatible battery or hybrid inverter installed first.
Solar batteries are complex devices — a self-installation should never be attempted.
Solar batteries are professionally installed by licensed or accredited solar installers.
The Climate Energy Council (CEC) also has strict regulations (AS/NZS 5139:2019) governing where and how your solar battery is installed. These standards are to be adhered to by your solar installer.
While installing your solar battery outdoors is a possibility, even if it is weather-resistant or IP-rated, exposing your solar battery to the elements is likely to shorten its lifespan.
If you intend to have your solar battery installed in your home, it cannot be installed in the locations below:
- Within a proximity of 600mm around and 900mm below the following:
- Opening windows and ventilation openings into a habitable room
- Within ceiling spaces
- Within wall cavities
- Within a 600m proximity of an exit with an opening of 900mm or less
- Electrical appliances within a 600mm proximity horizontally or 900mm above the installation site
- In a passageway, exit walkway exit, escape route or evacuation route
- Underneath an entrance walkway, exit walkway, staircase, evacuation route, escape route or passageway
- On top of roofs (unless the roof has a permanently installed or fixed staircase or ladder access)
- Sites where switchboards or solar generation systems are explicitly prohibited
- Sites where the battery’s manufacturer has explicitly prohibited
- An area with a high risk of vehicle damage
- Locations containing hazardous sources of ignition such as a gas meter for a switchboard.
Are solar batteries worth it?
Whether or not solar batteries are worth it depends on how you intend to use them.
If you live in a suburb that experiences frequent and prolonged outages, a solar battery with partial or full backup functions may be a necessity, especially if you need to maintain life-sustaining hardware.
For customers who prefer renewable energy sources, installing a solar battery to reduce their dependence on fossil-fuel-generated energy may be worthwhile for the environmental benefits alone.
Households on a controlled load or time of use tariff can also effectively harness varying rate structures to maximise their savings and lower the payback period of their solar batteries significantly.
This is not to say, however, that a household on a single rate tariff wouldn’t find any value in a solar battery. These customers may instead wish to focus on reducing their reliance on grid power as a means to reduce their electricity bills.
The best way to know whether you’ll benefit from a solar battery is by talking to a solar installer.
They’ll be able to take into account the different energy needs of your household and recommend a solution tailored to these needs.
If you are on the lookout for a solar installer, then be sure to check out our annual ratings on professionals in this area below.
Image credit: Sandy Schulze/Shutterstock.com
Original reporting by Kelseigh Wrigley
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