22 August 2025

Read This Before Adding a Solar Battery to Your Solar Panel System

Thinking about boosting your solar setup? Learn if you can add a solar battery to your existing solar system, the benefits, and key considerations.

If you’re one of the growing number of Australians who’ve already invested in solar panels, you’re probably wondering if you can add solar battery storage to your existing setup. The short answer is yes.

In most cases, you absolutely can add a solar battery system to your current solar panels and inverter. This upgrade can help you store the excess energy your panels generate during the day and use it when the sun isn’t shining, potentially saving you hundreds or even thousands of dollars on your electricity bills each year.

But, before rushing out to buy and install a solar battery, there are a couple of factors you need to consider first. In this article, we’ll walk you through everything you need to know about retrofitting your existing solar installation with battery storage, helping you make an informed decision that’s right for your home and budget.

Adding a Solar Battery to Your Solar System

Yes, adding solar battery storage to an existing solar setup is generally possible. For many households, this is the next step in becoming more energy independent and lowering bills.

Here are the main benefits:

• Increased self-consumption: Store excess energy during the day and use it at night.
• Lower energy bills: Reduce reliance on the grid and cut electricity costs.
• Backup power: Some solar batteries can provide power during blackouts.
• Environmental impact: Reduce your carbon footprint by using more renewable energy.

What You Need to Consider

Integrating a solar battery to an existing solar installation requires careful consideration of your energy usage patterns, system compatibility, and installer expertise.

Here are the key factors to keep in mind:

• Inverter Compatibility: Older solar systems often have standard grid connect inverters that may not be compatible with battery storage. You will need to upgrade to a hybrid inverter (which can handle both solar and battery functions)

• CEC Approval: All solar battery components must be Clean Energy Council (CEC) approved and installed by a CEC-accredited installer. This ensures your system meets Australian safety standards and maintains any existing warranties.

• Professional Installer Selection: A reputable installer can assess your current system, recommend the right battery size and type for your specific needs, and ensure proper installation while maintaining compliance with local regulations and electrical codes.

• Depth of Discharge (DOD): DOD indicates how much of the battery’s capacity can be safely used without damaging the battery. A higher DOD means you can use more of the battery’s stored energy, but it can also affect the battery’s lifespan if not managed properly.

• Battery Size and Usable Capacity: Consider both the battery’s nominal capacity (total storage) and usable capacity (the amount you can actually draw from the battery). The usable capacity is typically 80-95% of the nominal capacity, depending on the battery technology. Ensure the battery size aligns with your daily energy consumption patterns.

What Battery Size Should You Get?

As mentioned earlier, choosing the right solar battery system size depends on how much energy you use and when you use it. Let’s look at a real-life example.

A home with a 5kW solar system (no battery) recorded this energy usage over 89 days:

• Shoulder usage (late afternoon, early evening): 498 kWh
• Off-peak usage (night, early morning): 880 kWh
• Total demand outside solar hours: 1,378 kWh

Now using this quick formula (Total Shoulder + Total Off Peak) divided by the number of days, you’ll get: 15.48 kWh/day.

To cover this demand, we’d recommend a battery of at least 17kWh (factoring in a safety margin and the fact that batteries don’t fully discharge).

But here’s the catch: in this example, the existing solar system doesn’t produce enough excess energy to fully charge a 17kWh battery. This is where a KDEC expert can help. Sometimes, adding more panels alongside your battery is the best way to get the most out of your system.

Every home is different, which is why it’s important to get tailored advice before deciding.

Estimated Savings from a Solar Battery

So, you might be thinking to yourself, “What kind of savings can I expect if I add a solar battery to my current system?” For many households, the results are impressive.

A standard Australian household with a $1,850 annual electricity bill could save around $1,500 per year by adding a complete solar panel battery system.

These savings add up quickly over the typical lifespan of a quality battery system, often resulting in tens of thousands of dollars in reduced electricity costs. Many homeowners find that their battery system pays for itself within a couple of years.

Of course, your actual savings will depend on several factors:

• Your average energy usage patterns: Families who use more electricity during evening peak hours tend to see greater savings
• Your location: Different states and regions have varying electricity rates and solar feed-in tariffs
• The size of your solar battery system: Larger batteries can store more energy but require a higher upfront investment

Taking Advantage of Solar Battery Rebates

If you’re thinking about getting a solar battery, now is the best time to do so, mainly due to the current solar rebates and incentives available.

One of these is the Cheaper Home Batteries Program, which is a $2.3 billion federal initiative that can slash the upfront cost of a solar battery system by approximately 30%. For example, if you get a 13.5kWh battery, you could be eligible for a rebate of around $4,500.

This program doesn’t just support homeowners. It also applies to small businesses and community facilities, making clean energy more access

And the bigger your battery, the bigger your rebate.

With more than 4 million rooftop solar systems already installed nationwide, this rebate is a huge step toward energy independence.

Completing Your Solar Journey with KDEC

At KDEC, we understand that adding a battery to your existing solar system is a significant decision, and we’re here to make the process as smooth and straightforward as possible. Our team of accredited installers and energy experts has helped thousands of Australian families maximise their solar investment through smart battery solutions.

We’ll help you:

• Check your system’s compatibility
• Recommend the right solar battery size
• Handle the installation from start to finish
• Maximise your savings with available rebates

Don’t let rising electricity costs continue to impact your household budget. With generous government rebates available and battery technology better than ever, now is the perfect time to complete your solar journey with a quality battery system.

Contact KDEC today and let us help you unlock the full potential of your solar power system.