The lights come back. The air con does not.

Imagine a warm Adelaide evening. The street loses power, but your living-room lamp stays on. You reach for the air-conditioning controller, expecting the same result. Nothing happens.

“But we bought a battery. Isn’t that what it was for?”

This is an illustrative scenario, not a SunEnergy customer story. For a household with three-phase power, it points to a question worth asking before buying: does the proposed backup system actually supply the equipment you care about?

Three phase battery backup is not guaranteed simply because your home has three-phase power. A single-phase backup arrangement serves the circuits connected to that phase, not every circuit in the property. A system intended to support all three phases still needs its connected appliances and operating limits checked. The Australian Government’s inverter guide explains the single-phase backup distinction.

More batteries are going into homes. The important question is what yours will do.

On 29 September 2026, the Clean Energy Council reported that Australians installed 276,011 home batteries in the first half of 2026. That makes a battery a much more familiar purchase. It does not make every installation interchangeable.

If those headlines have brought a battery onto your shortlist, turn the conversation from “which box?” to “which parts of our home?” For one household, keeping food cold and a few lights available is the priority. For another, losing cooling is the very problem they wanted the battery to address. Those customers should not assume they are asking for the same installation.

Three-phase power at the house is only the starting point

A three-phase connection gives a property three electrical phases. Some appliances use one; others require three. Your home’s connection type does not tell you which type your air conditioner uses. Have the installer check its exact model and supply requirements rather than guessing from its size or the fact that it is ducted.

Also separate two questions: can this system operate with my home while the grid is available, and what can it power when the grid is gone? Government guidance allows for single-phase or three-phase solar inverters on a three-phase property. Compatibility during ordinary operation is not a promise of three-phase backup.

Think of the quote as needing a second description: not just the equipment being installed, but the household functions included when it is operating in backup mode.

Ask about your air conditioner, not just “whole-home backup”

Here is a useful sentence to take into a battery consultation: “During a blackout, I want this air conditioner available, along with the fridge and these lights. Is that included in this design?”

The answer should identify the appliance, whether its circuit is included, and the applicable output limits. If it cannot be supported in the proposed arrangement, you want to know before treating that quote as a cooling solution.

“Whole-home backup” can sound like permission to use everything as usual. It should instead start a discussion about exactly what is connected and what can run together. The Australian Government’s battery guide distinguishes selected-circuit, single-phase and whole-property backup, and warns against overloading the inverter during an outage.

This is not a reason to dismiss a smaller backup scope. If keeping the fridge and selected lights working meets your goal, that can be an intentional choice. The problem is paying for one outcome while picturing another.

A real example: the total rating is not the only limit

Sungrow Australia’s May 2021 SH5.0/10RT backup statement specifies a 3.33 kW per-phase off-grid load limit for the SH10RT. It says exceeding the applicable limit can cause a backup overload fault. This is a historical, model-specific example, not a specification for every current Sungrow product.

The useful lesson is not to memorise that number. It is to ask for the limits of the exact inverter you are being quoted. You cannot assume the headline system rating is available to any one appliance on any phase.

Newer products have different capabilities. Sungrow’s Australian SH5/10T product page, for example, describes support for unbalanced output in both backup and grid-connected operation. It is a different product family. Your installer must use the matching Australian documentation and load assessment, not transfer an older model’s limits to it.

Buy the backup outcome, not an assumption

Before requesting a home battery quote from SunEnergy in Adelaide, write down the two or three things you most want available during an outage. Add the air-conditioner model if cooling is one of them. If you do not know your supply type, say so; ask for it to be confirmed as part of the assessment. Do not remove switchboard covers to investigate.

Ask for the proposed backup scope in writing: which circuits are included, which are excluded, and whether your nominated appliance can operate alongside the other agreed loads. If there are two suitable approaches, ask what changes between them and what that means for the installed quote.

SunEnergy’s solar and battery enquiry is the place to discuss those priorities for your South Australian home. Start with the result you want us to assess, rather than asking for the biggest battery on the list. Our existing-solar battery guide covers the separate question of integrating with equipment already on the property.

Your battery plan should name what you want to keep working. “There is a battery on the wall” is not the same answer.