Can I Add a Battery to My Existing Solar PV System? 

Solar Battery

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Solar power is the most sustainable, eco-friendly, and clean source of electricity today. Solar cell technology is evolving rapidly, making photovoltaic cells more efficient and powerful in generating power. But how can I go about increasing the efficiency of my system? 

Adding a solar battery is a simple way to use the power your solar panels generate more efficiently. Excess power is stored and can be used later during times of high power usage or low sunlight. Solar batteries can be added to new and existing solar systems. 

That electric power can be fed directly to your home. However, you may also opt to store power using a solar battery bank connected to your array. Doing so allows you to power lights, fans, and other electrical appliances in case of an outage. Or, you can draw power from the batteries, reducing your reliance – and your bills – on the local grid.

The good thing is that with the help of a professional and a few extra components, you can have batteries installed and connected to your existing solar power array. Given how much a solar battery costs, having a professional help you with installation can help you keep initial and ongoing maintenance costs down. Let’s find out how.

Can You Add a Battery to an Existing Solar System? 

As a rule of thumb, you can add a new battery to an existing solar system installed on your property. However, the complexity and nuances of installation depend on your system’s original layout and design, and whether your system is intended for an additional battery. 

For example, if your solar system is old, did not incorporate a battery in the original design, or was not intended for battery installation, then having a modern battery installed would be difficult or even impossible. 

As time goes on, the design of solar batteries has improved, and modern batteries are easier to install than ever. Although some older solar systems may still be incompatible with modern solar batteries, we’re seeing fewer compatibility issues as time goes on. 

Is Your Existing Solar System Battery Ready?

If your solar power system is new or was designed to allow the addition of a battery, adding a battery inverter, a suitable battery, and a metering device should do the trick.

The inverter converts AC (alternating current) power to DC (direct current) power or the other way around. The metering device signals the battery inverter to store power when your system gives power back to the grid.

If your solar system meets the criteria above, it might be worth installing a solar battery. Selecting the correct type and size of battery for your system is more challenging than identifying whether your system is compatible with batteries.

How to Add a Battery to an Existing Solar System 

Adding a battery to your existing solar system is not as simple as you might think; it’s not just connecting a new battery bank. The process is complex, depends on your existing solar system, and is best left for professionals to do.

Why is it a complex process? Well, that’s because most grid-tie inverters are meant to convert DC from solar panels. However, in most cases, these devices are not designed to be incorporated with a battery bank. Generally, new components are needed to make your inverter compatible and work with your battery bank. 

Solar batteries are quite expensive; they are the costliest part of a modern solar system. The components and installation can cost you a few thousand dollars, depending on your system’s size and capacity. Although they progressive get more affordable each year, and most states in Australia have rebates, incentives or discounts for installing solar batteries, the initial upfront cost is still relatively high. 

Storage-ready Solar System 

The storage-ready solar system is usually more expensive than the DC- or AC-coupled systems. In this system, the existing grid-tie inverter is uninstalled. It is then replaced with a storage-ready inverter.

The storage-ready solar system is incredibly versatile since it works with existing grid-tied inverters. All you need is to choose a storage-ready inverter that is the same size and has a similar array wiring as your existing grid-tied inverter. 

DC Coupled System 

A DC-coupled system comprises the battery bank directly connected to the solar array. The connection is made by utilising a charge controller. This is the typical setup of an off-grid system.

It’s possible to replicate the DC-coupled system setup to a grid-tied system if a 600-volt string inverter is used. The inverter is installed between the solar array and the grid-tied inverter.

A DC-coupled system with a battery-based inverter can still automatically switch on to power your appliances. However, you need to manually switch on your solar array to charge your battery bank. This manual transfer means you must be on location to activate solar charging. 

AC Coupled System 

A grid-tied inverter is the heart of an AC-coupled system. The inverter continuously senses and monitors grid voltage and frequency. It automatically turns off if the voltage or frequency falls out of range. 

In this system, the grid-tied inverter is connected to an off-grid inverter and battery. Because the off-grid inverter supplies the system with a second power source, it “tells” it to stay online. Doing so allows you to charge your battery, which powers up your appliances when the power goes out.

Note that there are stringent guidelines in choosing the correct inverter and battery size. Wrong sizes for both components can cause the system to fail and perform sub-optimally. 

When is the Best Time to Add a Battery to Your Solar System? 

The cost of solar batteries has gone down a lot since their invention, and they are about as cheap as they have ever been, but they can still be too costly for some. Depending on your energy usage, it may be best to wait for prices to go down further. If you’re looking into them, speak to a solar specialist first. 

If your budget is tight, you might want to hold off on adding a solar battery for a few months to a few years and hope that battery prices drop. Fortunately, as new solar battery technology is introduced in the market, the prices of their older counterparts decrease, making them more affordable for you.

Another option while waiting for the right time to buy a solar battery is to prepare your system for battery storage. You will need to buy and install solar panels and an inverter. You can then purchase solar batteries once you can afford them.

How Much Does Adding a Battery to an Existing Solar System Cost? 

The prices of solar batteries can range from $1,000 to $2,000 per kilowatt hour; it all depends on your battery’s storage capacity. Note that these costs do not include installation charges, which could range to another $1,000.

If you start from the ground up (i.e., having to install a solar panel array), the cost may balloon anywhere from $2,000 to $ 12,000. 

Australian households that plan to have a solar system installed on their property commonly choose a system with a 4-kilowatt capacity. This has a price tag of $6,000 to $8,000.

Is it Worth Adding Battery Storage to Your Solar System? 

How worthwhile a solar battery is depends on your home energy usage and any incentives, rebates or discounts you are entitled to. WHile solar batteries do work, many find that their price to be too high to actually benefit from. Speak to your local solar specialist to find out if a solar battery is right for you. 

Solar batteries allow you to store power so you can still use your essential appliances whenever there’s a power outage. If your area of residence is known to experience frequent power outages or you live somewhere remote with limited or scheduled power transmission, investing in a solar power system and a battery can be an absolute boon, depending on how long your solar battery can power your house.

In addition, since you can draw power from your solar battery, you minimise your electrical consumption from the local power grid, saving you money. Finally, solar arrays and solar batteries are also eco-friendly. You can generate power while minimising your carbon footprint.

Again, while being environmentally conscious is important, saving money is one of the biggest determining factors behind purchasing a solar battery. As it stands, some homes in Australia don’t stand to save more money than they will spend on a solar battery, depending on the model. If you’re still interested in a solar battery, contact a solar installer to find out whether a battery is right for you. 

Related Questions 

Can I Add a Tesla Powerwall to My Existing Solar System?

Yes, you can integrate a Tesla Powerwall into an existing solar system. It is compatible with Solar Edge with a StorEdge interface, Fronius, Enphase micro inverter, Delta, SMA Sunny Boy, and ABB solar inverters. These inverters are widely available in Australia.

Tesla is also looking to partner with and enable its Powerwall to be compatible with other inverter brands.


The concept of solar batteries makes a lot of sense and in theory they are a great addition to any solar enabled home. However, unless you’re able to capitalise on a very generous incentive or rebate, it may not yet be cost-effective to invest in a solar battery. 


This article is published in good faith and for general informational purposes only. JFK Electrical does not make any warranties about the ongoing completeness and reliability of this information. Always seek personalised advice on solar energy to ensure any recommendations suit your property and scenario.

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