Perth homeowners often ask about solar battery backup. The Fronius GEN24 PLUS hybrid inverter is one of the most capable and proven backup options available. It pairs with a compatible battery: either the Fronius Reserva or BYD Battery-Box. It handles everything from essential circuit protection through to whole home backup. What it covers depends on the inverter size and your home’s phase configuration.
This guide covers what the Fronius GEN24 PLUS system backs up. It covers how single-phase and three-phase homes differ, and what to consider when sizing for backup in Perth conditions. Positive Energy Solutions installs Fronius GEN24 PLUS systems across the Perth metropolitan area.
The Inverter Is the Key: Why the GEN24 PLUS Determines Backup Capability
The Fronius GEN24 PLUS is a hybrid solar inverter. It manages both the solar panels and the battery in a single unit. When it comes to backup power, the inverter is the limiting factor, not the battery. Whether you pair it with a Fronius Reserva or a BYD Battery-Box HVM, the backup output depends on one thing: the GEN24 PLUS inverter size you have installed.
This matters for retrofit customers too. If you already have a Fronius GEN24 PLUS installed, adding a compatible battery gives you backup capability without replacing the inverter. The battery stores the energy. The inverter controls what gets backed up, and at what power level.
GEN24 vs GEN24 PLUS: Confirming Battery Compatibility
Not all Fronius GEN24 inverters are battery-ready out of the box. Some earlier GEN24 units need a software upgrade to the PLUS platform to enable battery compatibility. If you already have a Fronius GEN24 installed, and you are considering adding a battery, confirm which version you have before you proceed.
Easy check: take a photo of the sticker on the side of your Fronius inverter. Send it to your Positive Energy Solutions energy consultant. The sticker shows the model and firmware details. Your consultant can confirm on the spot whether your unit is PLUS-enabled, or needs an upgrade before a battery can be added.
For full product specifications on the Reserva and BYD Battery-Box, see our dedicated brand review posts linked at the bottom of this page.
Single-Phase Backup: What Each Inverter Size Covers
Positive Energy Solutions installs the Fronius GEN24 PLUS in 5kW and 10kW single-phase configurations. The backup capability is straightforward:
5kW — Essential Circuit Backup
At 5kW, the GEN24 PLUS backs up two essential circuits during a grid outage. Your installer will work with you to select which circuits to protect. These are typically lights, the refrigerator, and key power points. High-draw appliances, like air conditioning and the oven, are not backed up in this configuration.
The 5kW GEN24 PLUS, paired with a Reserva or BYD battery, is a strong choice. It suits homeowners who want reliable essential circuit protection with a proven inverter platform.
10kW — Whole Home Backup
At 10kW, the GEN24 PLUS backs up your entire home. Every circuit stays live during an outage. This is the configuration for homeowners who want no compromise when the grid goes down.
Load management note: even with whole home backup, running several high-draw appliances at once during an outage can overload the system. Do not stack air conditioning, electric cooktop, EV charger, and pool pump together. Prioritise what matters most, and let solar generation carry the load where possible.
Appliances not recommended to run simultaneously during an outage:
- Air conditioning (particularly large ducted systems)
- Electric cooktop or oven
- EV charger
- Pool pump
Lights, refrigerator, Wi-Fi, TV, and standard appliances all run comfortably. With solar generating during the day, the system can sustain whole home backup through extended Perth outages, with sensible load management.
Three-Phase Backup: What the GEN24 PLUS Delivers
For three-phase Perth homes, Positive Energy Solutions installs the Fronius GEN24 PLUS at 10kW. The three-phase GEN24 PLUS, with a compatible battery, backs up three essential circuits, one per phase, during a grid outage.
Three-Phase 5kW — Not Recommended for Backup
If you have a three-phase GEN24 PLUS at 5kW, and backup power matters to you, we recommend upgrading to the 10kW inverter. At 5kW across three phases, the available output per phase is limited. It does not deliver the reliable backup performance most homeowners need. The 10kW three-phase configuration is the right starting point for backup on a three-phase property.
Three-Phase 10kW — Three Essential Circuits
Three essential circuits cover the basics well. These are lights, refrigerator, and one additional circuit, such as key power points or a specific appliance. Your installer will work with you to identify the right circuits during system design.
For three-phase homes where whole home backup is the goal, the Fronius Verto Plus offers a solution — see below.
Fronius Verto Plus: Whole Home Backup for High-Draw Perth Properties
For Perth properties with significant power demand, Fronius offers the Verto Plus at 30kW. This covers larger homes, rural blocks with high usage, and properties prone to extended outages. This system delivers whole home backup capability on both single-phase and three-phase properties.
The Verto Plus mainly suits residential properties with high energy consumption. This includes rural blocks, larger homes running extensive air conditioning, and properties with significant equipment loads. It is not a standard residential system. But for the right property, it provides backup coverage that smaller inverter sizes cannot match.
If you think your property might suit the Verto Plus, speak to a Positive Energy Solutions energy consultant. We will assess your load profile, outage risk, and system requirements to confirm whether it is the right fit.
What Can You Run During an Outage?
Monitor Your System During an Outage: Fronius Solar.web App
The Fronius Solar.web app gives real-time monitoring of your GEN24 PLUS system during a grid outage. This includes battery state of charge, live solar generation, and current home consumption. Keeping the app open during an outage lets you make informed load management decisions, rather than guessing.
If the battery is depleting faster than solar is replenishing it, that is your cue to reduce load. Switch off a high-draw appliance, and let the system stabilise. On a sunny Perth day with good solar generation, the app will show you the headroom available. Active monitoring through Solar.web is the best way to keep the system running stably through an extended outage.
Rebates and VPP Eligibility
The Fronius GEN24 PLUS, paired with a DC-coupled battery (Reserva or BYD Battery-Box), is eligible for two rebates. These are the Federal Cheaper Home Batteries Program and the WA Residential Battery Scheme ($1,300 for Synergy customers). DC-coupled systems with an eligible battery on the WA Sustainable Systems List also qualify for Virtual Power Plant (VPP) programmes.
This makes the GEN24 PLUS system one of the more rebate-friendly backup options for Perth homeowners. It combines strong backup performance with access to the full rebate stack.
Speak to a Positive Energy Solutions consultant to confirm current eligibility and the rebate amounts that apply to your system size.
Why Positive Energy Solutions Installs Fronius GEN24 PLUS
The Fronius GEN24 PLUS is a proven hybrid inverter platform with a strong track record in Australian conditions. Its compatibility with both the Fronius Reserva and BYD Battery-Box gives homeowners flexibility. For retrofit customers who already have a GEN24 PLUS, adding a compatible battery is a clean and cost-effective path to backup power.
The system performs well across single-phase and three-phase installations. Combined with full rebate eligibility and VPP compatibility, this makes it a strong choice across a wide range of Perth homes.
Our team manages the full installation: system design, Western Power network application, rebate paperwork, and commissioning.
Talk to Positive Energy Solutions
If you are considering a Fronius GEN24 PLUS system with backup power capability, our team can help. We assess your home, recommend the right inverter size and battery, and confirm the rebate position.
Call us on 1300 180 999, or complete our online enquiry form, and we will be in touch within one business day.
Related guides
- Fronius GEN24 Plus Inverter Perth 2026: Full Review for WA Homeowners
- Fronius GEN24 Plus and Reserva: Why the Inverter and Battery Work Best Together
- Fronius Verto Plus Perth 2026: Full Home Backup for Three-Phase Homes
- SigEnergy SigenStor Backup Power for Perth Homes
Frequently Asked Questions
Does it matter which battery I pair with the GEN24 PLUS for backup?
Both the Fronius Reserva and BYD Battery-Box HVM work with the GEN24 PLUS, and deliver the same backup output. The inverter size determines what gets backed up, not the battery. The difference between batteries lies in usable capacity, how long backup runs, and pricing. Your Positive Energy Solutions consultant can compare the options for your home.
I already have a Fronius GEN24 PLUS — can I add a battery for backup?
Yes. If you have a GEN24 PLUS installed, adding a compatible Reserva or BYD battery gives you backup capability without replacing the inverter. This is one of the cleanest retrofit paths available to Perth homeowners. Contact us to confirm compatibility with your existing installation.
How long will the system run during an outage?
It depends on your battery capacity, consumption, and solar generation. During daylight hours with solar generating, the system can extend backup significantly. Solar charges the battery and powers your backed-up circuits at the same time. At night, backup duration depends on your battery’s state of charge and what you are running.
Is the Fronius GEN24 PLUS suitable for three-phase whole home backup?
The 10kW three-phase GEN24 PLUS backs up three essential circuits, one per phase. For three-phase whole home backup, the Fronius Verto Plus at 30kW is the right solution for properties with the right load profile. Talk to a Positive Energy Solutions consultant to assess which option suits your home.
Are there rebates available for a Fronius GEN24 PLUS with battery?
Yes. DC-coupled GEN24 PLUS systems with an eligible battery qualify for the Federal Cheaper Home Batteries Program and the WA Residential Battery Scheme. Eligible batteries on the Sustainable Systems List also qualify for VPP programmes. A Positive Energy Solutions consultant will confirm what applies to your specific system at quote stage.
What is the difference between the Fronius Reserva and BYD Battery-Box for this system?
Both batteries are compatible with the GEN24 PLUS, and deliver the same backup output through the inverter. The main differences are in usable capacity options, modular scalability, and pricing. See our dedicated Fronius Reserva review and BYD Battery-Box review for full specifications.
I have an existing Fronius GEN24 — is it compatible with a battery?
It depends on whether your unit is PLUS-enabled. Some GEN24 inverters need a software upgrade to the PLUS platform before a battery can be added. The easiest way to check is to take a photo of the sticker on the side of your inverter, and send it to a Positive Energy Solutions consultant. We can confirm compatibility straight away, and advise on next steps.
About the Author
Jason Wiktorowicz
Sales Manager, Positive Energy Solutions | Perth, WA
Jason has been at the centre of Western Australia’s energy transition for over a decade. As Orchestration Lead on Project Symphony — WA’s largest virtual power plant pilot — and Stream Lead on Project Encore, he worked directly with AEMO, Western Power and Energy Policy WA to shape how distributed energy resources connect and operate on the SWIS. That work included developing and rolling out CSIP-AUS, now mandatory for all new WA grid connections. He also led Emergency Solar Management (ESM), the first program of its kind in WA, VPP for Schools (VPP4S), which provided direct market benefits through Supplementary Reserve Capacity, and REBAR, the WA Residential Battery Rebate scheme.
His earlier career spanned Synergy, Infinite Energy and Curtin University’s Sustainability Policy Institute, where he co-authored peer-reviewed research on net-zero urban precincts, solar integration and peer-to-peer energy trading, published in the journal Urban Planning in 2018.
At Positive Energy Solutions, Jason leads sales with a focus on system design accuracy and long-term performance. Positive Energy Solutions installs solar and battery systems, EV chargers and heat pumps, and holds partner accreditations with Fronius, SigEnergy, iStore and SunPower. Connect with him on LinkedIn.
