Best Batteries for Homes with Existing Solar (Retrofit Guide)

Over 3.6 million Australian homes have solar panels. The majority of those installed before 2022 don't have battery storage. If that's you, the question isn't just "which battery should I buy?" — it's "which battery will actually work with what I already have?" This retrofit guide covers both.

The Retrofit Challenge

Adding a battery to an existing solar system is different from designing a new system from scratch. Your existing solar inverter may or may not be battery-compatible, and the coupling type (AC vs DC) depends on your current setup.

The first question your installer should answer: What inverter do you currently have, and what's its condition?

If Your Existing Inverter Is Compatible with DC Coupling

Some existing hybrid-capable inverters can have a battery added without replacement. If you already have a Sungrow hybrid inverter, a Fronius Gen24, a SolarEdge StorEdge, or similar hybrid-ready unit, you may be able to add a DC-coupled battery directly. Your installer should assess this.

DC-Coupled Retrofit Batteries

• Sungrow SBR (pairs with Sungrow SH hybrid inverter — may require inverter upgrade)
• BYD Battery-Box HVM (compatible with multiple hybrid inverters)
• Fronius Solar Battery (pairs with Fronius Gen24)

If Your Existing Inverter Is a Standard String Inverter

Most Australian homes have a standard string inverter (Fronius Primo, SMA Sunny Boy, ABB, older Sungrow string models). These cannot directly manage a DC-coupled battery. Your options:

Option A: AC-Coupled Battery (Keep Existing Inverter)

AC-coupled batteries have their own inverter built in. They work alongside your existing solar inverter without replacing it. This is the most common retrofit approach.

Best AC-coupled options for retrofits:

• Tesla Powerwall 3 — the most popular retrofit choice in Australia. Works with almost any existing inverter. 13.5 kWh, 11.5 kW output. CHBP eligible. Easiest installation.
• Enphase IQ Battery 5P or 3T — best if you already have Enphase microinverters. Excellent compatibility and monitoring. CHBP eligible.
• sonnenBatterie eco — premium AC-coupled option. Works with existing inverters. Higher price point.

Option B: Replace the Inverter with a Hybrid (DC Coupling)

If your existing inverter is old (8+ years) or showing problems, consider replacing it with a hybrid inverter as part of the battery installation. Yes, this adds cost — but:

• You'd likely be replacing a failing inverter soon anyway
• DC coupling is 3–5% more efficient than AC coupling
• You get a cleaner, more integrated system

Best hybrid inverter + DC battery combinations for retrofits:

• Sungrow SH series + Sungrow SBR — most widely installed combination in Australia, excellent support
• Fronius Gen24 + BYD Battery-Box — premium option with wide compatibility
• GoodWe ET + GoodWe Lynx — emerging strong option for cost-conscious retrofits

Key Compatibility Considerations

Export Limiting

Many existing solar connections have export limits set by the DNSP. Adding a battery may trigger a review of your export connection — check with your installer about potential DNSP approval requirements. In some cases, adding a battery actually helps (it can reduce export requirements by storing what would have been exported).

Switchboard Condition

Older switchboards (particularly those without a safety switch) may need upgrading to support a battery installation. Your installer should assess this during the site visit. Don't let an installer skip the switchboard assessment — it affects both safety and the final installed cost.

Smart Meter

A smart interval meter is required for most CHBP-eligible installations and for optimal battery management. If you don't already have one, your installer should arrange an upgrade as part of the installation (your retailer may provide this free, or there may be a cost).

The Recommended Path for Most Retrofitters

For a household with a 3–7 year old string inverter in good condition:

1. Get quotes for AC-coupled battery (Powerwall 3 or Enphase IQ)
2. Ask installer to assess whether your current inverter is likely to last another 5+ years
3. If inverter is aging or struggling: get quotes for hybrid inverter + DC battery replacement instead
4. Compare total 10-year cost including likely inverter replacement scenario