The short answer: three-phase is a design input, not an upgrade promise
A three-phase supply can give a home more ways to be designed for solar, a battery, backup and larger electric loads. It does not automatically mean that a battery balances every phase, keeps every circuit on during an outage, keeps the existing inverter, or turns an EV into a home-energy source.
The Australian Government explains that a battery stores energy for later use and may provide outage power when it is designed and configured for backup. On a three-phase property, the backup outcome may cover the whole property, selected essential circuits, or only one phase—depending on the battery, inverter, wiring and final design.[1]
The useful question is not “Do I have three-phase?” It is: “What will this exact design do at my house, and what will it not do?”
First, separate the three things people often combine
1. Three-phase supply
A three-phase supply distributes electricity across three active phases. It can support higher-capacity electrical designs, but it does not define how a proposed battery connects or how outage power is arranged. The Australian Government notes that a three-phase property may use either a single-phase or three-phase inverter; network connection and export conditions still apply to the approved design.[2]
2. Battery energy and battery power
kWh is stored energy: how much energy is available in the battery. kW is power: how much the battery/inverter can supply at one time. A larger kWh figure does not, on its own, mean a home can run every appliance together during a blackout. Starting loads, inverter output, selected circuits, solar conditions and household demand all matter.[1]
3. Backup scope
A quote should state whether it is for:
- essential-circuit backup — selected items such as lighting, refrigeration, communications or chosen outlets;
- one-phase backup — a single-phase battery/hybrid inverter backing only circuits connected to that phase on a three-phase home; or
- a broader or whole-home backup design — a designed arrangement that identifies phase treatment, output limits, protection, switchgear, operating settings and load limits.
Those are different products of design. Do not let the phrase “three-phase” replace a written blackout scope.
What a three-phase battery proposal needs to answer
Before you compare brands or capacity, ask for these answers in writing:
| Question | Why it matters |
|---|---|
| Is the home’s supply single-phase or three-phase, and how are the phases currently used? | It establishes the starting electrical arrangement. |
| Does the proposed battery/inverter connect to one phase or three? | It determines the intended architecture; it is not safe to infer from a battery brand. |
| Which loads and phases are intended to operate during an outage? | It distinguishes essential circuits, one-phase backup and a broader design. |
| What are the continuous and surge output limits in kW or kVA? | It helps set realistic expectations about simultaneous appliance loads. |
| What usable battery capacity and stated runtime scenario are being used? | Runtime depends on selected loads and conditions, not a generic “hours of backup” promise. |
| Can solar recharge the battery while islanded, and under what configuration? | Grid-connected solar-only systems normally stop in an outage for anti-islanding safety; a backup-capable design is different.[1] |
| Does the current solar inverter stay, change or take a different role? | Existing-inverter compatibility and warranty treatment require exact evidence. |
| What distributor application, switchboard, meter, protection or cable work is included? | NSW connection and electrical-safety requirements can change the delivery path. |
Can a single-phase battery work at a three-phase house?
Potentially, but the limitation needs to be made clear. The Australian Government says that a single-phase battery or hybrid inverter on a three-phase property provides backup only to circuits connected to its one phase.[2]
That may suit a household whose resilience priority is a small, intentionally selected group of loads. It is not the same as phase balancing or three-phase backup. A designer should map the proposed backed loads and phase arrangement before the contract is signed.
Does three-phase mean whole-home backup?
No. Whole-home backup is a specific electrical design, not an automatic property of a three-phase supply or a Gateway/controller.
Manufacturer documentation can show how some products support either partial-load or full-home backup configurations. For example, Enphase’s Australian installation guide illustrates both arrangements for its equipment. It also treats the controller/gateway as a defined part of the system, not a substitute for the main switchboard.[3]
That is useful product context, not a promise that every three-phase home, appliance or motor can run during an outage. The final answer depends on the exact equipment, rated output, phases, protection, switchboard, wiring, commissioning, selected loads and network requirements.
Some systems also have a short transition before backup supply takes over. If an uninterrupted supply is needed for a particular device, ask whether a separate UPS requirement applies; a standard battery backup design should not be described as a UPS without confirmation.[4]
Existing solar and inverter compatibility
Adding a battery to existing solar can be assessed, including at a three-phase home. It is not safe to assume that the current inverter will remain or that any battery will communicate with it.
NSW guidance says the proposed battery should be confirmed as compatible with the inverter manufacturer, and it notes that a switchboard upgrade may be required.[5]
Your proposal should identify the existing panel and inverter models, whether the system is AC- or DC-coupled, the role of each inverter, required communications and protection, warranty position, meter/switchboard work and distributor approval. See our existing solar and battery retrofit guide for the full evidence checklist.
What do current STC requirements change?
The Commonwealth’s current Cheaper Home Batteries Program works through Small-scale Technology Certificates (STCs). It is not a universal NSW cash rebate.
The Clean Energy Regulator says eligibility has conditions for the new battery, connected inverter, capacity, eligible PV pairing, approved equipment, standards, VPP capability where applicable and accredited installation. It also distinguishes the first claimed battery system at a grid-connected premises from later additions or expansions.[6]
A useful proposal should separate:
- the pre-STC equipment and installation price;
- the current eligibility assumptions and certificate calculation;
- the agreed pass-through or assignment treatment; and
- what changes if the live rules, equipment listing, site evidence or approval position changes.
The Clean Energy Council’s Approved Batteries list is dynamic. It is used by programs and networks, but inclusion does not guarantee performance, savings, an export limit or a particular backup outcome.[7]
What about a three-phase EV charger or V2H?
Three-phase EV charging and vehicle-to-home (V2H) are separate questions.
An ordinary AC charger is not automatically bidirectional. Charging speed depends on the vehicle and available supply, and a vehicle’s charging port alone does not demonstrate that it can export energy to a home.[8]
For V2H or V2G, confirm the exact vehicle and model year, manufacturer capability and warranty position, compatible bidirectional charger, communications/software, electrical protection, phase arrangement and applicable network or regulatory requirements. Hyundai Australia, for example, says its vehicles do not support or permit V2G charging in Australia at the time of its guidance.[9]
Do not attach a V2H claim to a three-phase battery quote unless that separate pathway is explicitly specified and verified.
A confident next step
Collect recent bills or interval data, existing solar/inverter details, switchboard and meter photos, a list of future loads and a clear blackout priority. Then ask for one written, phase-specific design.
Cable Co’s Energy Assessment can help organise that starting information. It is not electrical design, a certificate, a distributor approval, a compatibility decision, an STC entitlement, finance approval, fixed-price quote, backup guarantee or V2H commitment. Final scope requires a qualified site review and written proposal.
Sources and review date
Reviewed on 26 September 2026 using current Australian Government, NSW Government, Clean Energy Regulator, Clean Energy Council and manufacturer guidance. Product lists, program terms, network requirements, equipment firmware, vehicle support, prices and site conditions can change. Confirm the current position for the exact property and configuration before contracting.
Sources & references
- Australian Government Solar Consumer Guide, Batteries. ↩
- Australian Government Solar Consumer Guide, Inverters. ↩
- Enphase, Energy System Installation Compliance Guide. ↩
- Clean Energy Council, Guide to installing a household battery storage system. ↩
- NSW Government, Guide to owning a battery. ↩
- Clean Energy Regulator, Solar batteries. ↩
- Clean Energy Council, Approved Batteries. ↩
- Tesla Australia, Home Charging. ↩
- Hyundai Australia, Vehicle-to-Grid (V2G) Explained. ↩