Three-Phase Battery Installation

A three-phase battery comes down to three decisions

If your home has three-phase power, a battery quote has to answer three questions that a single-phase home never asks. What will the battery take off the bill when the house is spread across three phases? What stays on in a blackout: one phase, or all three? And how big a system will the network let you connect? Get those right and the brand almost picks itself.

Deionno Electrical & Solar has installed solar and batteries across Adelaide for ten years and now on the Sunshine Coast, with our own licensed electricians. We are a certified installer for Sigenergy, Sungrow and Tesla Powerwall, and we install GoodWe. Three of those four make true three-phase battery systems, and we’ve fitted them on new builds, on established homes with a switchboard upgrade, and on houses with an EV charger on the wall.

Does a three-phase home need a three-phase battery?

No. The supply to your house and the battery you put on it are two separate choices, and plenty of three-phase homes run happily on a single-phase battery.

A single-phase battery connects to one of your three phases. It costs less, and for cutting the bill it does nearly everything a three-phase battery does. A three-phase battery connects to all three. It can deliver more power, it can run three-phase appliances, and it can back up the whole house. Which one you need comes down to the next two sections.

How a battery cuts the bill on a three-phase supply

A three-phase home has one meter, and that meter adds the three phases together before it records what you bought or sold [1]. So when a battery on one phase is discharging while the oven and the air conditioner are drawing on the other two, the meter sees power going out on one phase and coming in on the others, and counts only the difference.

The practical result: a single-phase battery can cover the usage on all three phases as far as your bill is concerned, up to the power it can put out. The monitoring has to measure all three phases for it to work, which is part of the install.

What a single-phase battery can’t do is physically push power into the other two phases, and in a blackout that’s the whole story.

What stays on in a blackout: one phase or all three

When the grid goes down, the meter’s arithmetic stops helping. Only the circuits the battery is physically connected to can run.

• A single-phase battery backs up one phase. We plan which circuits sit on that phase before anything is wired: usually the fridge, the lights, the internet and the power points you’d miss most. Anything three-phase stays off.
• A three-phase battery backs up all three. Every room stays on, and three-phase appliances can run, as long as the total stays inside what the inverter can deliver.

There’s one catch with three-phase backup. The inverter’s power is shared across the phases, so a 15 kW unit doesn’t give 15 kW to one phase. Put the kettle, the oven and the dryer on the same phase and it can trip while the other two sit idle. The Sungrow 15, 20 and 25 kW hybrids are built to carry uneven loads across the phases [4], and whatever the brand, we balance the circuits across the board as part of the job.

Three-phase batteries we install, side by side

The figures come from each maker’s own documents, because installer websites don’t always agree.

Sigenergy on a three-phase home

Sigenergy is on most of the three-phase jobs shown on this site. The inverter and the battery modules stack into one tower, the three-phase inverter comes in six sizes from 5 to 30 kW, and battery modules are added to the stack as needed. Sigenergy’s DC car charger can join the same stack. For backup, the Sigenergy gateway sits between the street and the switchboard and takes the whole house, or the circuits you choose, off the grid when it fails.

At Banya on the Sunshine Coast, a new three-phase home has a 15 kW Sigenergy inverter, 27 kWh of battery and a Sigenergy EV charger, with the whole house backed up except the air conditioning. At Glandore in Adelaide, a 25 kW system backs up the full house.

Sungrow three-phase hybrid inverters and batteries

Sungrow’s three-phase hybrid range runs from 5 to 25 kW, paired with a Sungrow battery tower beside it. The inverter does the solar and the battery in one unit, so there’s one box on the wall and one app.

The larger three, at 15, 20 and 25 kW, have the backup changeover built in, rated for a whole home, and switch over in a fraction of a second [4]. At Vale Park we fitted a 15 kW Sungrow hybrid with 30 kWh of battery and a three-phase main switch upgrade. At Mount Pleasant, a 20 kW hybrid runs with 35 kWh.

Tesla Powerwall 3 on a three-phase home

Powerwall 3 is a single-phase battery. On a three-phase home it connects to one phase, its Backup Gateway works with a three-phase supply, and in a blackout it carries the circuits on its own phase [6]. For bill savings that’s fine. For whole-home backup on three phases, or for running a three-phase air conditioner in an outage, it’s the wrong tool and we’ll tell you so.

The Tesla Powerwall installation page covers the Powerwall in full.

Three-phase loads: ducted air conditioning, pool and bore pumps, EV chargers

These are the loads that decide the design.

• Ducted air conditioning. Larger units are three-phase. They can run from a three-phase battery if the inverter is big enough, but air conditioning empties a battery quickly, so many owners choose to leave it off the backup. Banya is set up that way.
• Pool and bore pumps. Often three-phase on larger blocks. On a property that relies on a bore for water, the pump is usually the first thing people want backed up.
• EV chargers. A 7 kW charger is single-phase. An 11 or 22 kW charger is three-phase. Either can be left off the backup so the car doesn’t drain the house battery overnight.

We list what is on each phase at the assessment and you decide what stays on, before the quote.

Network limits in South Australia and South East Queensland

• South Australia. SA Power Networks allows up to 10 kVA of solar inverter and 10 kVA of battery inverter on each phase, so up to 30 kVA across a three-phase home, and a hybrid inverter counts toward both. The output has to be balanced to within 5 kVA between any two phases. Export is either fixed at 1.5 kW per phase or flexible up to 10 kW per phase [2].
• South East Queensland. Energex has to approve the system before it is installed, and an approved three-phase system has to spread its output evenly across the three phases. Where the local network is full, Energex may offer a smaller system, a lower export limit or a dynamic connection [7].

We lodge the application in both states, and the design you sign is the one the network has agreed to.

Battery size and the federal battery rebate

Three-phase homes tend to be bigger homes, and the temptation is a very big battery. The federal rebate tapers off as the battery gets bigger. From 1 May 2026 the first 14 kWh of usable capacity earns the full rate, the part from 14 to 28 kWh earns 60 percent of it, and the part from 28 to 50 kWh earns 15 percent [8].

So the rebate pays best on the first 14 kWh and tails off after that. We size the battery from a year of your bills and the loads you want backed up, then show you what the rebate does to each option. Our battery rebate calculator gives a figure for your postcode. We do not sign customers up to a virtual power plant. A battery can join one later if you choose.

Three-phase battery installation in Adelaide and on the Sunshine Coast

Adelaide and South Australia

Most of our three-phase battery work so far is in Adelaide: Sigenergy systems in Glandore, Goodwood, Gawler East and Sheidow Park, and Sungrow hybrids in Vale Park and Mount Pleasant. We cover the metro area, the Hills, the Fleurieu and the Barossa from Salisbury Plain. See the Adelaide battery installation page.

Sunshine Coast and South East Queensland

On the Coast, three-phase power turns up most on newer and larger homes, usually for ducted air conditioning or a car charger. Recent Sigenergy three-phase jobs include Banya, Buderim and Mooloolaba. Our electricians cover Caloundra to Noosa, the hinterland, Gympie and north Brisbane from Corbould Park. See the Sunshine Coast battery installation page.

Choosing the installer

A three-phase battery is more switchboard work than any other battery job. The solar battery installer page covers what to check before you sign with anyone.

Sources

1. SolarQuotes, Home batteries on three-phase supplies, updated December 2025.
2. SA Power Networks, Technical Standard TS129, issued 16 July 2025.
3. Sigenergy, SigenStor Australian brochure and three-phase datasheet.
4. Sungrow, SH15T, SH20T and SH25T hybrid inverter datasheet, and SH5T to SH25T user manual.
5. GoodWe, ET G2 three-phase hybrid inverter datasheet (Australia).
6. Tesla, Powerwall 3 datasheet (Australia).
7. Energex, Connection essentials and Assessment criteria and application outcomes.
8. Clean Energy Regulator, Battery rebates are changing from 1 May 2026.