Most Australian homes have a single-phase electricity supply. But a growing number — particularly newer homes, homes with large solar systems, and homes with three-phase appliances — have a three-phase supply. The phase configuration of your home affects which batteries are compatible and how they're installed.
What does single-phase vs three-phase mean?
Your home's electricity supply comes from the grid via either one phase (single-phase) or three phases (three-phase). Single-phase delivers 230V on one conductor; three-phase delivers 230V on each of three conductors (or 400V between any two phases).
Three-phase supplies can deliver more power simultaneously, which is why larger homes, homes with large solar systems (above 10 kW), and homes with three-phase appliances (large air conditioners, some EV chargers) often have it.
How do I know which I have?
Look at your switchboard. A single-phase connection has one main switch; a three-phase connection has three. Alternatively, ask your installer or check with your network operator.
Battery options for single-phase homes
All major battery brands work with single-phase homes. This includes Tesla Powerwall, GoodWe ESA, Sungrow SBR, Enphase IQ, and BYD Battery-Box.
Single-phase batteries are simpler, cheaper, and cover the vast majority of Australian residential installations.
Battery options for three-phase homes
Three-phase homes have two options:
Option 1: Single-phase battery on one phase. This is the simplest approach. The battery connects to one of the three phases and only directly offsets that phase's consumption. Energy cannot flow between phases (this is a grid limitation, not a battery limitation). This works fine if your home's load is reasonably balanced across phases.
Option 2: Three-phase battery system. Some batteries are available in three-phase configurations — either a single unit with three-phase output (such as Sungrow SBR with a three-phase hybrid inverter) or three separate single-phase units (one per phase). This allows the battery to independently manage all three phases.
Does phase matter for backup power?
Yes, significantly. A single-phase battery on one phase of a three-phase home can only back up that phase. If your critical loads (refrigerator, lighting, medical equipment) are spread across all three phases, a single-phase backup won't cover them all.
If backup power is a priority in a three-phase home, a three-phase battery or careful load management (moving critical loads to the battery's phase) is important.
Cost implications
Three-phase battery systems cost more than single-phase equivalents — both for the hardware and the installation. Expect to pay 20–40% more for a properly configured three-phase system.
For many three-phase homes with balanced loads, a single-phase battery on one phase is perfectly adequate and represents better value. Your installer should assess the phase balance of your home before recommending a configuration.
Getting the right recommendation
Our battery calculator includes a three-phase configuration option that adjusts the sizing recommendation and flags compatibility considerations based on your inputs.