How Many Solar Batteries Do You Really Need to Power Your Home

In 2025, more Australian homeowners are adding batteries to their solar systems than ever before. With rising electricity prices, blackouts in some regions, and the appeal of energy independence, batteries are no longer a luxury — they’re becoming a smart investment.

But one of the most common questions people ask is: “How many solar batteries do I actually need to power my home?” The answer isn’t the same for everyone. It depends on your energy usage, lifestyle, and goals. Let’s break it down so you can make a confident, informed decision.

Understanding Solar Batteries: The Basics

A solar battery stores the excess electricity generated by your solar panels during the day. Instead of sending it back to the grid, you can use that stored energy at night or during cloudy weather.

In Australia, the most common type of solar battery is lithium-ion, particularly Lithium Iron Phosphate (LiFePO4), which is known for its long lifespan and safety.

• Typical home batteries: 5 kWh – 13.5 kWh capacity

• Average lifespan: 10–15 years or around 6,000–10,000 cycles depending on brand and usage

Step 1: Look at Your Energy Usage

The first step to working out how many batteries you need is to understand your daily electricity consumption.

Check your power bill for your average daily usage, measured in kWh (kilowatt-hours).

• Small households (1–2 people): ~10–15 kWh/day

• Medium households (3–4 people): ~15–25 kWh/day

• Large households (4–5+ people, pool, EV charging): ~25–40+ kWh/day

Example: If your family uses 20 kWh per day and you want to cover most of your night-time needs, you’d need a battery of around 10–13 kWh.

Step 2: Decide Your Energy Goals

Not all homeowners want the same outcome. Your goals will affect how many batteries you need:

 1. Lower Energy Bills

If your aim is to maximise savings, a single battery (around 10–13 kWh) is often enough for a standard family. It covers evening usage when solar panels stop producing.

 2. Backup Power in Blackouts

For households in regions with frequent blackouts (like parts of South Australia), you may want enough capacity to run essentials such as fridges, lights, Wi-Fi, and medical equipment. This might mean two smaller batteries or one large unit.

 3. Going Fully Off-Grid

If you want complete energy independence, you’ll need a much larger battery setup. In Australia, an off-grid household usually requires:

• 20–40 kWh of usable storage

• Often achieved with two or more batteries plus a generator backup for long cloudy periods

Step 3: Factor in Climate and Location

Australia’s diverse climate plays a big role in how many batteries you need.

• South Australia: High sunshine hours, great for battery charging, but also prone to heatwaves and grid instability.

• Queensland & WA: Plenty of sun, but high summer demand from air conditioning may mean extra capacity is needed.

• Victoria & Tasmania: Shorter winter days mean households may need larger batteries or occasional grid reliance.

Step 4: Understand Battery Warranties and Lifespan

Most home solar batteries in Australia come with a 10-year warranty. But performance may decline over time due to battery degradation.

• After 10 years, a typical lithium-ion battery retains around 70–80% of its original capacity.

• This means a 13.5 kWh battery may deliver only around 10 kWh after a decade.

When planning how many batteries you need, it’s worth factoring in this gradual decline.

Step 5: Costs and Payback

Solar batteries are a significant investment.

• Single 10–13 kWh battery: $9,000 – $14,000 installed (prices vary by brand and installer)

• Larger off-grid systems with multiple batteries: $20,000 – $40,000+

The good news is that with high electricity prices and feed-in tariffs trending lower, batteries are offering faster payback times than in previous years — often 7–10 years for many Australian households.

Practical Example: A South Australian Home

Let’s say you live in Adelaide, and your household uses 22 kWh per day.

• Daytime use (solar directly): 10 kWh

• Night-time use: 12 kWh

A single 13.5 kWh battery would be enough to cover your night-time usage, with a little left for cloudy days. If you added an EV or heated pool in the future, you might need a second battery.

Tips to Get the Right Battery Size

• Check your bills first: Base your decision on actual usage, not guesses.

• Think ahead: Consider future energy needs like EVs or all-electric heating.

• Don’t oversize unnecessarily: Extra batteries add cost without benefit if you don’t use the storage.

• Choose a SAA-approved installer: Always use Solar Accreditation Australia–accredited installers to ensure safety and warranty protection.

Why Choose AR Energy for Your Battery Needs

At AR Energy, we specialise in designing tailored solar and battery solutions for Australian households. Whether you’re looking to cut down on power bills, add reliable backup for blackouts, or move closer to energy independence, our team provides expert guidance and accredited installation. With years of experience in South Australia, we understand local conditions and can recommend the perfect battery setup for your home.

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Conclusion:

Bigger isn’t always better when it comes to solar batteries. The right number depends on your household’s usage, goals, and location. For most Australian families in 2025, one well-sized battery (10–13 kWh) is enough to slash bills and boost energy independence. Going fully off-grid, however, will require multiple batteries and careful planning.

Ready to explore your solar battery options? Start by checking your energy bill and contact with a local SAA accredited installer about the best fit for your home.

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