Can I add a battery to my existing solar?
Can I add a battery to my existing solar system?
It’s one of the most common questions we get from homeowners across Geelong, the Surf Coast and the Bellarine: “I already have solar — can I just add a battery?” In most cases, yes. Retrofitting a battery to an existing solar system is one of the jobs our in-house crews do most often, and it’s usually a tidy two-to-three day install.
Here’s what actually matters when you’re thinking about it.
Will a battery work with my current solar?
Most modern batteries are designed to sit alongside an existing solar array. There are two common ways to do it:
- AC-coupled: the battery has its own inverter and connects to your switchboard. This is the flexible option and works with almost any existing solar setup.
- DC-coupled: the battery ties in more directly with your solar inverter. Neat and efficient, but it depends on your current inverter being compatible.
When our team comes out, the first thing we check is your existing inverter, your switchboard space and how your solar is currently performing. That tells us which battery brands and connection methods suit your home. We install a range of quality batteries including Tesla Powerwall, SigEnergy and BYD, so we can match the battery to your system rather than forcing your system to fit the battery.
How big a battery do I need?
This comes down to how much power you use in the evening, once the sun’s down and your solar has stopped producing. A good starting point is your latest power bill — one recent enquiry mentioned an average of around 49kWh a day, which is a very different sizing conversation to a smaller household.
As a rule of thumb, you want enough battery to soak up your daytime solar surplus and carry your home through the evening peak, without paying for capacity you’ll never fill. Our battery storage guide walks through the trade-offs, and our sales team will size it against your real usage rather than a generic estimate.
What about backup during a blackout?
Not every battery keeps your home running during an outage by default — backup capability depends on the battery model and how it’s wired in. If keeping the fridge and a few lights on through a blackout matters to you, tell us upfront and we’ll design for it. It can change which battery makes sense, so it’s worth raising early.
Is it still worth it with the current rebates?
Yes — the federal Cheaper Home Batteries Program currently provides an upfront discount on eligible batteries through small-scale technology certificates. Importantly, that discount steps down each January and July, so the value isn’t fixed. We won’t quote you a figure from a blog post — instead, get in touch for today’s exact discount for your situation.
The old $1,500 Victorian battery rebate has finished, and the state battery loan has closed, so ignore anything online that still mentions those — the federal discount is the current incentive.
A few things to check before you commit
- Inverter age and warranty: older inverters may need attention when you add a battery.
- Switchboard space: some homes need a small switchboard upgrade for safety compliance.
- Future EV charging: if a car charger is on the horizon, plan the battery and switchboard around it now.
Our 8 tips for choosing a solar and battery combo is a handy read before you decide.
Talk to a local team
We’ve been installing across Geelong, the Surf Coast and the Bellarine since 2011, with our own crews rather than subcontractors. If you’ve got solar and you’re weighing up a battery, we’ll come out, look at what you’ve already got, and give you a straight answer. Call (03) 5243 8364 or get in touch.
