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WA battery guide

Adding a battery to an existing solar system in WA

A structured starting point for WA property owners and installers assessing retrofit compatibility, connection requirements, rebates and commissioning.

Assess the existing system Arrange an assessment
Maintained by
PSW Energy
Status
Published · reviewed
For
Customers, Installers
Discuss a battery retrofit
Maintained byPSW EnergyPublishedReviewed
For

Customers, Installers

Discuss a battery retrofit
01 / Assess the existing system

Start with the system already on site

Begin with the existing installation, not the battery catalogue. Since 1 May 2026, adding a battery in the South-West Interconnected System is assessed as an upgrade of the whole installation: the existing solar system is checked against current connection requirements alongside the new equipment, and the outcome can change the viable design.

Existing equipment and household needs

  1. Record what is already installed

    Identify the solar inverter, panel array, switchboard condition, metering arrangement, network settings and any existing export limit before selecting a battery architecture.

  2. Size against the load profile

    Compare daytime generation, evening consumption, seasonal demand and intended backup loads. Rebate ceilings do not establish the appropriate battery size for a property.

Compatibility and approvals

  1. Confirm the complete configuration

    Check the battery, inverter, gateway, firmware and communications requirements as one system. Existing equipment may need reconfiguration or additional hardware.

  2. Identify the controlling network rules

    Confirm whether Western Power or Horizon Power requirements apply, then check the retailer functionality settings and supported product lists relevant to the site. An addition is assessed as an upgrade of the whole installation under the requirements commencing 1 May 2026, so a design that keeps the existing inverter must be confirmed as a supported configuration before it is quoted.

  3. Separate technical fit from eligibility

    Federal certificates, the WA scheme, vendor accreditation and virtual power plant participation have distinct requirements. Eligibility should be confirmed before a contract relies on an incentive.

Basic Embedded Generator Connection Technical Requirements (opens in a new tab)New requirements for solar and batteries: information for installers and retailers (opens in a new tab)

Commissioning and handover

  1. Plan commissioning and records

    Allow for testing, electrical certification, photographs, serial numbers, customer documents and registration steps before installation work begins.

Solar batteries (opens in a new tab)
02 / Common questions

Compatibility questions to settle early

Can a battery be added to an existing solar system?

Often, yes. The WA scheme recognises additions to existing solar, but the viable design depends on the inverter, network connection, supported equipment and virtual power plant requirements. Some sites require a gateway, reconfiguration or replacement equipment.

Does the existing solar equipment need to appear on the current approved product list?

The Clean Energy Regulator states that an existing solar PV system paired with a new eligible battery must comply with electrical safety requirements, but the existing PV equipment does not need to appear on the current Clean Energy Council approved list.

What battery capacities can qualify for federal certificates?

Current Clean Energy Regulator guidance sets a nominal capacity range of 5 to 100 kWh, with certificates applying to the first 50 kWh of usable capacity. Eligibility is assessed under the rules applying to the installation and claim.

Does adding a battery change the requirements applying to the existing solar?

Yes. Under the WA connection requirements commencing 1 May 2026, an addition brings the entire installation under assessment against current requirements, not just the new equipment. Depending on the existing inverter and configuration, that can mean reconfiguration, additional compliance equipment, or migrating the existing panels onto a new inverter rather than retaining the old one.

Should the battery be selected before reviewing consumption data?

No. Consumption timing, export, future loads and backup priorities should shape the design before a specific capacity or product is selected.

03 / Connection and eligibility

Confirm the requirements for the whole installation

Review network requirements alongside product and program eligibility. A suitable battery and a supported complete installation are different checks.

Check current WA scheme eligibility requirementsConfirm eligibility for an addition to existing solar on the Energy Policy WA scheme eligibility page before it becomes a contract assumption. (opens in a new tab)
Clean Energy RegulatorSolar batteries (opens in a new tab)Energy Policy WAWA Residential Battery Scheme eligibility requirements (opens in a new tab)Energy Policy WAInformation for industry (opens in a new tab)Western PowerBasic Embedded Generator Connection Technical Requirements (opens in a new tab)Energy Policy WANew requirements for solar and batteries: information for installers and retailers (opens in a new tab)
04 / Arrange an assessment

Bring the existing system into the discussion

Contact PSW Energy or Perth Solar Warehouse with the existing inverter brand and model, approximate installation age and current export limit.

Discuss a battery retrofit

PSW Energy and Perth Solar Warehouse assess solar and battery requirements across Western Australia.

Discuss a battery retrofit
05 / Further reading

From retrofit design to handover

Further reading follows the assessment: existing equipment, connection and program settings, then safety and records.

Assess the existing system

Check programs and connection settings

Verify safety and evidence

06 / Related guides

Continue the property assessment

Battery incentives and scheme eligibility in WA

Separate federal certificates, WA rebates, loans and virtual power plant conditions before relying on an advertised battery discount.

WA solar and battery compliance centre

Current operational references for installers and retailers working across WA solar, battery storage and distributed energy connections.