Can I add a battery to my existing solar? What to check first

Adding a battery later is common, and it means you can see how much solar you export before you choose a size. energy.gov.au notes that with an existing system, you can usually keep your solar inverter and add a battery inverter. Whether that’s the best route for your home depends on the age of your inverter, the kind of solar you have, and whether you want backup.

The two ways to add a battery

Both work. energy.gov.au describes AC coupling as the usual arrangement for adding to an existing system, while a hybrid inverter suits a new solar and battery install, or an old inverter that’s near the end of its life. Our guide to solar inverters explains the types.

What decides which suits your home

• Your inverter’s age. If it’s near the end of its warranty, ask for a second quote that replaces it with a hybrid inverter, so you can compare.
• Microinverters. If you have one on each panel, a hybrid inverter isn’t an option; you need an AC-coupled battery.
• Backup. If you want power in a blackout, ask how each option handles it. Some AC-coupled batteries can restart your solar during an outage; others can’t.
• Phases. On a three-phase supply, a single-phase battery only backs up one phase.

Check your existing system qualifies for the discount

The Cheaper Home Batteries Program discount applies to batteries installed with existing solar of up to 100 kW. DCCEEW’s rules add two conditions when you keep your inverter: it must be on the Clean Energy Council’s approved inverter list, and the system must meet electrical safety rules. An inverter that has dropped off the list can still qualify, unless it was declared ineligible or delisted for safety reasons.

The battery itself must be on the Clean Energy Council’s approved battery list, and the installer must be accredited by Solar Accreditation Australia with a battery endorsement.

Network approval and export limits

Adding a battery usually means a new application to your distributor (the company that runs the poles and wires), which your installer handles. energy.gov.au says a connection agreement can take up to 30 business days in some areas, and it can include a limit on how much you export.

Approval can change the design between the quote and the install. Make sure any change, and what it does to the price or your savings, is explained and agreed in writing before work starts.

Size the battery to the solar you have

With existing solar, you already have the best data there is: your bills. A battery can only store what you export, so look at your exported solar and your night-time use. Our guide to what size battery you need walks through it. If your system is small, adding panels as well may make more sense.

Questions to ask before you sign

• Is my inverter on the approved list, and will you keep it or replace it? Why?
• What’s the usable capacity, and how many STCs does the quote include?
• Will the system back up my home in a blackout? Which circuits, and can the solar keep charging the battery?
• Who applies to the distributor, and what happens if they set an export limit?
• Who covers the warranty if the old inverter and new battery don’t work together?

Batteries built to add to existing solar include the AC-coupled picks on our best home batteries list. You can also find battery retailers that service your postcode and check a retailer’s accreditation.

This guide is general information, not financial or legal advice. Rules, rebates and prices change, so check the linked sources before you decide. Facts checked 22 October 2026.