How Do Solar Batteries Work? A Simple Guide for Australian Homes
Solar panels generate electricity while the sun is shining, but many households use the most energy in the morning and evening. Without a battery, excess daytime solar is usually exported to the grid or, in some cases, limited by export restrictions.
A solar battery lets you store some of that excess energy and use it later. This can help you use more of your own solar power, buy less electricity from the grid and take greater control of how your home uses energy.
What is a solar battery?
A solar battery is a rechargeable battery designed to store electricity generated by rooftop solar panels.
Instead of sending all your unused solar energy to the grid, your system can direct it into the battery. The stored energy can then help power your home when your panels are not generating enough electricity, including at night, during cloudy weather or at times when electricity costs more.
Most home batteries available today use lithium-ion technology because it offers strong performance, a long operating life and relatively low maintenance.
How does a solar battery work?
A typical solar and battery system automatically directs energy to where it is needed.
The basic process works like this:
- Your solar panels capture sunlight and generate direct current electricity, known as DC electricity.
- An inverter converts the DC electricity into alternating current electricity, known as AC electricity, which your household appliances can use.
- Your home uses the available solar electricity first.
- Any excess solar energy can be used to charge the battery.
- Once the battery is full, additional solar energy may be exported to the grid or limited, depending on your system and local export conditions.
The system manages this energy flow automatically. You do not need to manually switch between solar, battery and grid electricity.
What happens during the day?
During daylight hours, your solar panels generate electricity for your home.
The electricity will generally be used in this order:
- Power the appliances currently running in your home.
- Charge the battery with available excess solar energy.
- Export any remaining electricity to the grid, where permitted.
This means your dishwasher, washing machine, air conditioner and other appliances can use solar energy directly while the battery stores energy for later.
What happens at night?
When your solar panels stop generating electricity, the battery can begin supplying your home.
The battery stores electricity as DC power. When that energy is needed, an inverter converts it into AC electricity for your household appliances.
If the battery reaches its minimum charge level, or your home requires more power than the battery can provide at one time, the electricity grid can automatically supply the difference.
What happens on cloudy days?
Solar panels can still generate electricity in cloudy conditions, although usually less than on a clear day.
Your home may use a combination of:
- Electricity generated by the solar panels
- Energy stored in the battery
- Electricity supplied by the grid
How much stored energy is available will depend on the weather, your battery’s charge level and how much electricity your household has used.
Will a solar battery work during a blackout?
A battery can provide power during an outage, but only when the system has been designed and configured for backup operation.
Standard grid-connected solar systems normally shut down during a blackout. This is an important safety feature that prevents electricity from being sent into powerlines while technicians may be working on them.
A backup-capable battery system can disconnect your home from the grid and supply selected essential circuits or, depending on the design, more of the property. Backup requirements should be discussed before installation because not every battery provides this function automatically.
Learn more about battery backup and installation considerations through the Australian Government’s Solar Consumer Guide.
What are the benefits of a solar battery?
Use more of your own solar energy
A battery allows you to store excess solar rather than immediately exporting it. This can increase the proportion of your household electricity supplied by your own solar system.
Reduce electricity purchased from the grid
Using stored solar energy in the evening may reduce the amount of electricity you need to buy from your energy retailer. Actual savings will depend on your energy usage, electricity rates, feed-in tariff and system design.
Store energy for when you need it
Solar energy generated in the middle of the day can be saved for the evening, overnight or during periods of higher household demand.
Access backup power
A properly configured backup system may keep selected appliances operating during a blackout. This could include lighting, refrigeration, internet equipment or other essential circuits.
Make smarter use of electricity rates
Some battery systems can be configured around time-of-use electricity prices. Depending on the system and energy plan, the battery may store energy when electricity is cheaper and use it when grid prices are higher.
Participate in a Virtual Power Plant
Compatible batteries may be able to participate in a Virtual Power Plant, or VPP. A VPP connects eligible batteries so they can help support the electricity grid. Eligibility, payments and access conditions vary between programs.
Understanding battery capacity and power
Two measurements are particularly important when comparing batteries.
Battery capacity, measured in kWh
Kilowatt-hours, or kWh, measure how much energy the battery can store.
A battery with greater usable capacity can generally supply your home for longer, but the right size depends on how much electricity your household uses and when you use it.
Battery power, measured in kW
Kilowatts, or kW, measure how much power the battery can deliver at one time.
A battery may have enough stored energy to run your home for several hours but still be unable to operate every high-powered appliance simultaneously. Large loads such as air conditioning, pool equipment, electric cooking and EV charging should be considered when designing the system.
Can a battery be added to an existing solar system?
In many cases, yes.
An existing solar system can often be expanded with an AC-coupled battery, which uses a separate battery inverter. This can be a flexible option when the existing solar inverter is still suitable.
A new solar and battery installation may use a DC-coupled arrangement with a hybrid inverter. This allows electricity from the panels to charge the battery before it is converted into AC electricity.
The best arrangement depends on your existing equipment, system age, switchboard, available installation space and future energy needs.
How long does a solar battery last?
Battery life varies between products and depends on factors such as:
- How frequently the battery charges and discharges
- The amount of energy moved through the battery
- Operating temperature
- Installation conditions
- Battery chemistry
- Manufacturer and product quality
Battery warranties may be expressed in years, charging cycles, energy throughput or a combination of these. It is important to compare usable capacity, warranty conditions and the level of Australian technical support, not just the upfront price.
Are solar batteries eligible for a government discount?
Eligible battery installations may receive an upfront discount through the Australian Government’s Cheaper Home Batteries Program.
The program began on 1 July 2025 through an expansion of the Small-scale Renewable Energy Scheme. Eligible systems can create small-scale technology certificates, which are commonly assigned to the retailer or installer in return for an upfront reduction in the purchase price.
Program settings changed on 1 May 2026, and the available discount depends on factors including the battery’s usable capacity, installation date and current eligibility requirements.
Eligible installations must use approved products and appropriately accredited installers. Program rules and incentive values can change, so your quote should confirm the current discount available for your property.
Visit the Clean Energy Regulator for current program information.
Is a solar battery worth it?
A battery may be a strong option if you:
- Generate excess solar energy during the day
- Use significant electricity in the evening or overnight
- Receive a relatively low feed-in tariff for exported solar
- Want to reduce your reliance on grid electricity
- Want backup power during outages
- Plan to add an electric vehicle or other electric appliances
- Want greater visibility and control over your household energy use
The right answer depends on your home. Your electricity bills, solar generation, usage patterns, available space and budget should all be considered before choosing a system.
A larger battery is not automatically better. A properly sized system should be matched to the energy your household is likely to generate and use.
What should you consider before getting a battery?
Before choosing a system, ask about:
- Compatibility with your existing solar system and inverter
- Usable battery capacity
- Maximum power output
- Whole-home or essential-circuit backup
- Warranty length, cycles and throughput conditions
- Monitoring through an app or online portal
- Installation location and safety requirements
- Current government discounts
- Virtual Power Plant compatibility
- Ongoing product support in Australia
A tailored assessment can help you avoid paying for capacity you may not use or selecting a battery that cannot meet your backup and power requirements.
Ready to store more of your solar energy?
A well-designed solar battery system can help you use more of the electricity your panels generate, reduce grid purchases and take greater control of your home energy.
Nectr Solar & Battery can review your household energy needs, existing solar system and future plans to recommend a suitable solution.
