Are you considering adding a battery to your home solar system? With the Australian government’s new Cheaper Home Batteries Program set to start on July 1, 2025, this might be the perfect time.
This program offers a significant rebate, making battery installations more affordable for households and small businesses.
At PSC Energy, we’ve seen prices fluctuate with rebates. It can be confusing to navigate that without insight you can trust. We’re a bit biased when it comes to sizing solar batteries, but we’re educators first and foremost today.
In this article, you’ll learn about the following:
- What Size Solar Battery Should I Buy?
- Why Smaller Isn’t Always Smarter for Solar Batteries
- Crunch the Numbers for a Solar Battery, but Be Honest with Yourself
- FAQ: Choosing the Right Home Battery Size in Australia
Let’s explore how this initiative can help you maximise the benefits of your solar investment and enhance your energy independence.
What Size Solar Battery Should I Buy?
When most people start looking into home batteries, their first question is usually, “What size battery should I get?” That seems like a simple and logical place to start. But it overlooks something more important.
Before selecting a size, ask yourself: “What do I want my battery to do for me?”
That’s the real first question, and your answer to it will shape every other choice.
Some people want a battery that saves them the most money (cheapest). Others want one that keeps the lights on during a blackout. And many want both. However, depending on your unique needs and goals, the best battery size can vary from one customer to the next.
If your primary goal is to achieve a quick return on investment, you’ll want a smaller battery. More storage equals more money. But if your goal is to have power during blackouts or to be more energy independent, then a larger battery might be the smarter choice.
This is why knowing what matters most to you. Is it money, backup power, or long-term peace of mind? Those questions should be addressed before looking at the kilowatt-hours.
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Why Smaller Isn’t Always Smarter for Solar Batteries
Many people believe that the smallest battery that can pay for itself quickly is the best choice. That’s because when a battery is small, it’s easier to use all its energy every day. The more often you fully cycle your battery (charge and discharge it), the faster you see savings. That’s the logic behind the advice you might hear, like, “Just get a 5 kWh battery.”
And for some households, a 5 kWh battery might be enough…at first.
However, this only works if your goal is to achieve the fastest return on your investment. If your goals include blackout protection, future-proofing, or reliable winter performance, that small battery may not be enough.
Let’s look at why.
Blackouts and Backup Power
Imagine there’s a blackout on your street. Everyone’s in the dark except your house. If your battery has sufficient reserve power, you can keep your lights on, your fridge running, and even your Wi-Fi connected.
But if your battery is too small, you might not have any power left when the power goes out.
Most blackout-ready homes reserve about 5 kWh for emergencies. If your battery is only 5 kWh, that doesn’t leave much for your everyday needs. And if you’ve used up most of your battery during the day, that 5 kWh might not even be there when you need it.
Winter Shortfalls and Peak Pricing
Smaller batteries also struggle more in winter. There’s less sunlight during the day, and households often use more electricity in the evening.
A tiny battery may not last through those long, cold nights. You may need to top up from the grid, and if that happens during peak pricing hours, your savings will shrink quickly.
A larger battery provides a better buffer during the winter months when sunlight is low and electricity use is high. It helps you avoid tapping into expensive peak grid power at night. And because it holds more energy, you’re less likely to run short even after a cloudy day.
What a Bigger Battery Buys You
If your budget allows it, investing in a larger battery now can save you headaches later. With the new federal rebate, those extra kilowatt-hours come at a significant discount (approximately one-third of the price), making larger batteries more affordable than ever.
A larger battery provides more than just additional storage. It gives you confidence, comfort, and control.
More Reliable Backup in Blackouts
With a larger battery, you can keep more of your home running when the grid goes down. Lights, fridges, internet, and even a few appliances can stay on for hours (or even overnight) if your battery is big enough.
You won’t need to pick and choose what stays on and what shuts off. That kind of backup power can be a real game-changer, especially if you live in an area with regular outages.
Built-In Protection Against Degradation
All batteries lose capacity over time. But if your battery starts big, you’ll still have useful storage even after ten years.
For example, if a 10 kWh battery drops to 70% capacity, it still gives you 7 kWh. That’s more than enough for basic home use. That helps future-proof your setup and reduces the likelihood of needing to replace your battery prematurely.
That means a 5 kWh battery could shrink to about 3.5 kWh over time. It might still work, but it won’t do as much. You’ll spend more time charging it and less time using it. And at some point, you may wonder if it’s still worth it.
A small battery might look good on paper today. But in real life, years down the track, it may feel more like a short-term fix than a smart investment.
Peace of Mind
You might not see this in a spreadsheet, but peace of mind matters. Knowing that your battery will keep you powered during a blackout, handle cold nights, and continue to perform for years can make a real difference in how satisfied you feel with your solar investment.
Choosing a bigger battery isn’t reckless. It’s not wasteful. It’s a different kind of rationale.
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Crunch the Numbers for a Solar Battery, but Be Honest with Yourself
Running the numbers is important. You should always know what you’re spending and what you’re likely to save. That’s how you make sure the battery pays for itself over time.
But numbers aren’t everything. You also need to be honest about what matters most to you.
If your only goal is saving money, then yes, a smaller battery might give you the quickest return. You’ll use it up almost every day, and over a few years, you’ll likely cover the cost through savings on your power bill.
But if your goal is to keep your home running during blackouts, avoid grid use during peak times, or future-proof your setup as energy prices rise, the “fastest payback” battery might leave you disappointed. You could end up with a battery that’s too small to handle the job in real life.
So yes, crunch the numbers. But also, be honest with yourself about what you expect from your battery. Is it only about dollars? Or do you also want comfort, confidence, and control?
This is your home. It’s not just a math problem. It’s your daily life, and your battery should fit the way you live.
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Ready to Take the Next Step?
To help you make an informed decision, consider the following actions:
- Research Approved Battery Systems: Ensure the battery and inverter you choose are listed on the Clean Energy Council’s approved product list.
- Consult Accredited Installers: Work with installers accredited by Solar Accreditation Australia to ensure your system meets all safety and compliance standards.
- Evaluate Your Energy Needs: Assess your household’s energy consumption patterns to determine the battery size that best suits your needs.
By taking these steps, you can make a well-informed decision that aligns with your energy goals and take advantage of the benefits you’ll receive from available rebates. At PSC Energy, we’re ready to guide you through these decisions. We’ve helped thousands of customers navigate the solar waters. It’s what we do.
If you’re interested in learning a bit more about the federal solar rebate, also known as the Federal Cheaper Home Batteries Program, you might want to check out the following article titled, What the 2025 Federal Election and the Government Rebate Means for Solar Batteries in Australia.
FAQ: Choosing the Right Home Battery Size in Australia
What size home battery do I need in Australia?
The right battery size depends on your goals. If you want fast payback, a 5 kWh battery may be enough. If you want blackout protection and long-term reliability, a larger battery (7–13 kWh) may be a better choice.
Is a 5 kWh battery big enough for my home?
A 5 kWh battery can work for small households focused only on saving money. However, it may fall short in blackouts, during winter, or as it degrades over time.
How much capacity should I reserve for blackouts?
You should reserve at least 2 kWh for backup power if you want lights, Wi-Fi, and a fridge to stay on during a blackout.
How long do home batteries last?
Most batteries are warranted to retain 70% of their capacity after 10 years. A 10 kWh battery could still provide 7 kWh after a decade, making it more useful long-term than a smaller system.
What is the Australian federal battery rebate in 2025?
The Cheaper Home Batteries Program starts July 1, 2025. It offers up to 30% off the cost of a battery system for eligible homes and small businesses, with higher support for energy-stressed households.
Can I combine the federal battery rebate with state rebates?
Yes. You can combine the federal rebate with state-based incentives available, depending on your location.
Do I need to join a Virtual Power Plant (VPP) to get the rebate?
No. Joining a VPP is optional under the federal scheme, but it can offer extra savings and income if you choose to participate.
However, there is a VPP rebate in New South Wales that can pay back up to $1,500 for connecting to a Virtual Power Plant.
How do I get the rebate for a home battery in Australia?
To qualify, use products from the Clean Energy Council’s approved list and hire an installer accredited by Solar Accreditation Australia. The installer will apply the rebate at the point of sale.
Is a larger battery worth the extra cost?
Yes, if you want better blackout protection, less reliance on the grid in winter, and a longer-lasting system. The rebate makes bigger batteries more affordable right now.
What should I consider before buying a home battery?
Think about your energy goals (savings, backup, or both), your household usage, available sunlight, and how long you want the system to last. Crunch the numbers, but also think about comfort and future-proofing.
