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Yes, you can often add a battery without replacing your solar. Before choosing one, check whether your panels and inverter are still doing their job. There is no reason to replace equipment that works unless the new system needs it.
Storage alongside your existing solar
Adding storage to an existing system is called a battery retrofit. Your solar supplies the house first. Surplus can charge the battery for use after sunset, instead of going straight to the grid.
Three ways to add storage
The condition of your existing system usually points to one of these options.
Already have a battery-ready hybrid inverter? Ask which batteries it supports before paying for a replacement. “Battery-ready” does not mean every battery will work.
Site and system checks
Age alone is not a reason to replace your solar. We need to know whether it is safe, producing as expected and leaving enough surplus for storage.
- Your equipment: inverter model and age, panel capacity and recent generation.
- Your property: single- or three-phase supply, switchboard, meter, battery location and internet connection.
- Your usage: electricity bills or interval data, evening demand and plans for an EV or other large loads.
- Your backup needs: the circuits you want running during an outage, and whether the battery, inverter and gateway support them.
Send photos of the inverter label and the outside of the switchboard, plus a recent bill. Do not remove electrical covers to take a photo.
WA approvals and rebates
Your installer needs to check the retailer and network requirements for the completed system, including any solar inverter you keep. Check the Synergy supported equipment list and Western Power connection requirements before ordering.
The WA Residential Battery Scheme requires an eligible battery and participation in an approved Virtual Power Plant (VPP). A VPP lets an operator coordinate batteries across participating homes. Read the contract before joining.
The federal Cheaper Home Batteries Program is separate. Its Small-scale Technology Certificate (STC) discount depends on the installation date, eligible capacity and certificate value. Have both amounts and eligibility confirmed in your quote. See our WA battery rebate guide, the WA eligibility rules and the federal battery program for current terms.
What stays on in a blackout?
A battery does not automatically give you backup. It needs compatible equipment, often a gateway or changeover device, and the right circuits connected. Without that, it may shut down when the grid fails.
What can run at once?
Backup output limits the appliances you can run together. Air conditioning or EV charging needs more power than lights and a fridge.
How long can it run?
Usable capacity and the charge left when the outage starts affect runtime. Using more power drains that stored energy faster.
Ask for the backed-up circuits to be named in the quote. Do not assume “backup included” means the whole house. If you rely on medical equipment, discuss a separate outage plan with your care provider.
The complete retrofit quote
Compare the complete installed price, with these items made clear:
- Battery, inverter, gateway and any equipment being removed or retained.
- Installation, cabling, switchboard work and backup circuits.
- Approvals, commissioning, monitoring and VPP setup.
- Rebate assumptions, exclusions, warranty and aftercare.
Start with the equipment you own and the power you use after sunset. We can then work out whether to keep your solar, change the inverter or upgrade both. Explore adding a battery, or get a quote for your existing system.