Existing-solar battery retrofit

Keep what works. Change only what the new system needs.

Adding a battery is not a single wiring recipe. The right retrofit depends on how your existing solar produces, measures and exports power—and what you expect the home to do when the grid is down.

Two common pathways

The energy path matters more than the brand name.

Keep the solar inverter

An AC-coupled battery system can measure the home at the AC side and charge from surplus generation while the existing solar inverter remains in service. Metering, export control and blackout operation still need to be designed as one system.

Move to a hybrid architecture

A hybrid inverter can manage compatible PV and battery inputs together. This may require changes to PV strings, protection, metering and the grid application. “Hybrid” describes the architecture; it does not prove every existing panel layout is ready to move across.

The final choice requires complete equipment models and the current Australian manufacturer documentation. Similar product names or a shared brand are not enough to prove compatibility.

Compatibility check

What we need to verify before recommending equipment.

  • Existing inverter brand, full model and approximate age
  • Single- or three-phase supply and existing DER arrangement
  • Available solar generation, export and evening consumption
  • Switchboard condition, metering and practical cable route
  • Preferred battery location and access constraints
  • Essential circuits or whole-home backup expectations
  • Large loads such as air conditioning, pumps and EV charging
  • Current manufacturer compatibility and commissioning pathway

Start with the inverter label.

A clear photo of the full model, plus your suburb and a recent bill, is enough for us to tell you what still needs checking.

Check my existing solar

Retrofit questions

The details that change the answer.

Can every existing solar system take a battery?

Most homes have a workable retrofit path, but not every battery connects directly to every inverter. The current inverter, PV strings, phase, metering, export settings and the desired blackout behaviour must be checked before selecting the architecture.

Do I have to replace my existing solar inverter?

Not always. An AC-coupled battery pathway may allow the solar inverter to stay. A hybrid inverter replacement can make sense when the existing unit is incompatible, ageing, undersized for the intended design or when a different backup arrangement is required.

Will my existing solar keep charging the battery during a blackout?

It depends on the system architecture and equipment. Grid-disconnected operation requires a deliberately designed energy path and compatible controls; it should never be assumed from the fact that solar and a battery are both installed.

What should I send for a compatibility check?

Send the inverter brand and full model, a recent bill, the property phase if known, clear switchboard and inverter photos, and a short list of the circuits you want available during an outage.

Follow SUNNY LinkedIn Follow SUNNY Facebook