If your main reason for buying a battery is keeping the fridge, lights and internet (or the whole house) running when the grid fails, the spec that matters is not kWh. It is backup power in kW, how fast the system switches over, which circuits are wired to it, and whether it can run three-phase loads. This guide compares seven battery systems on exactly those points, using our full reviews of each product.
It is independent desk research based on manufacturer datasheets, Australian warranty documents, Solar Victoria guidance, published pricing and owner and installer reports. Solar Cobber did not test any system in a real outage, did not request quotes, and no manufacturer paid for inclusion. One warning up front: Solar Victoria advises that owning solar and a battery does not automatically mean you have power in a blackout. Backup has to be designed in.
Quick picks
- Best Overall for Blackouts: Tesla Powerwall 3, for 10 kW of backup and strong motor-starting in one box.
- Best Value Whole-Home Backup: Sungrow SH10RS with an SBR battery, for near-instant switchover at a lower price.
- Best for Three-Phase Backup: Sigenergy SigenStor, which backs up all three phases.
- Best for Fronius Homes: BYD Battery-Box Premium with a Fronius GEN24 Plus, if a short outage is acceptable.
- Best Budget Essential-Circuit Backup: AlphaESS SMILE-G3, for fridge, lights and internet on a tight budget.
- Best for Long Outages on a Budget: Fox ESS EQ4800, for the most kWh per dollar.
- Best for Light Loads in Enphase Homes: Enphase IQ Battery 5P, which adds backup in 5 kWh steps.
Comparison table
| System | Continuous backup power | Switchover | Whole home or circuits | Three-phase backup | Price guide (2026) | Best for |
|---|---|---|---|---|---|---|
| Tesla Powerwall 3 | 10 kW typical (5 kW in WA) | Not published | Whole or partial home via Gateway 2 | No, one phase | A$10,000 with Gateway after discount, plus install | Single-phase whole home |
| Sungrow SH10RS + SBR | 10 kW (SH10RS), 8 kW (SH8.0RS) | Under 10 ms | Whole home via 63 A bypass | Yes, SH T series | SBR128 A$8,100 after discount, plus inverter and install | Value whole home |
| Sigenergy SigenStor | Set by controller and modules (10 kW SP, 15 kW peak) | 0 ms with Gateway | Via Sigen Energy Gateway | Yes | A$8,000 for 13 kWh after discount, plus install | Three-phase homes |
| BYD + Fronius GEN24 Plus | About 6.2 kW battery power (Primo 6.0 Plus) | 10 s listed; about 40 s reported | Full Backup with extra hardware | Yes, Symo 6.0 to 12.0 | HVM 13.8 A$8,100 after discount, plus inverter and install | Fronius owners |
| AlphaESS SMILE-G3 | 5,000 VA (S5), 10,000 VA (T10) | Not published | Backup port circuits | Yes, T models | A$4,600 for 9.6 kWh after discount, plus install | Essentials on a budget |
| Fox ESS EQ4800 | Set by Fox inverter | Not published | Inverter dependent | Yes, H3 inverters | Not published | Long outages |
| Enphase IQ Battery 5P | 3.84 kVA per unit | Not published | Via IQ System Controller 3 INT | Limited, 1.28 kVA per phase per unit | A$8,100 to A$10,100 installed for one unit before discount | Light loads |
“After discount” means after the federal Cheaper Home Batteries discount at May to December 2026 rates. Every product links to a full review on our battery reviews hub.
Best Overall for Blackouts: Tesla Powerwall 3
The Tesla Powerwall 3 delivers 10 kW of continuous power in most states and is rated to start loads of up to 185 locked-rotor amps, which helps with air conditioners and pool pumps. Tesla’s datasheet lists whole-home and partial-home backup through the Backup Gateway 2, and the built-in solar inverter recharges the battery from your panels during an outage. It is the simplest strong-backup option for a single-phase home.
Pros
- 10 kW continuous (5 kW in WA, up to 11.04 kW configured) from one unit
- 185 A locked-rotor rating for motor starts
- Solar recharges the battery during a multi-day outage
Cons
- Single phase only: on a three-phase home it backs up one phase and cannot run three-phase appliances
- Charging is capped at 5 kW, which limits how much a short winter day can refill
- Tesla does not publish a switchover time in its Australian datasheet
- Needs a grid connection, so it is not an off-grid product
Key specs: 13.5 kWh usable, 10 kW continuous, 185 A LRA, IP67. At full output it lasts about 1 hour 20 minutes; at 1 to 2 kW, most of a night.
Price and warranty: About A$10,000 with Gateway after the discount, before installation (SolarQuotes, May 2026). 10 years to 70%, with unlimited cycles for backup and self-consumption.
Skip it if you are on three-phase power and want every phase backed up.
Best Value Whole-Home Backup: Sungrow SH10RS with SBR
The Sungrow SH RS hybrid paired with a Sungrow SBR battery is the value route to whole-home backup, but only with the right model. The SH8.0RS and SH10RS have a built-in 63 A bypass for the whole house, 8 or 10 kW of off-grid output, a 13.68 kVA peak for 10 seconds and a switchover Sungrow lists as under 10 ms.
Pros
- Under 10 ms switchover, so most appliances ride through
- Whole-home bypass on the SH8.0RS and SH10RS
- Three-phase SH5T and SH10T add a 63 A bypass and 100% unbalanced output
Cons
- The cheaper SH5.0RS and SH6.0RS back up only a dedicated circuit, at 5 or 6 kW
- The battery also limits output: an SBR128 is rated 7.68 kW continuous, so 10 kW of backup needs a bigger stack
- SolarQuotes notes high start-up loads such as pressure pumps can struggle in backup
- Tied to Sungrow batteries
Key specs: SH10RS 10 kW off-grid, 13.68 kVA peak for 10 s, 50 A battery current; SBR 9.6 to 25.6 kWh.
Price and warranty: An SBR128 is about A$8,100 after the discount, plus about A$3,600 for a 10 kW Sungrow hybrid and installation (SolarQuotes, May 2026). Inverter 10 years; battery 10 years to 70% with unlimited backup and self-consumption cycles.
Skip it if a quote names an SH5.0RS but promises whole-home backup. That combination cannot deliver it.
Best for Three-Phase Backup: Sigenergy SigenStor
The Sigenergy SigenStor is our pick for three-phase homes because its three-phase controllers (5 to 30 kW) back up all three phases, so three-phase air conditioners and pumps can keep running if the system is sized for them. Sigenergy states 0 ms load-side disruption when the Sigen Energy Gateway is installed, and the 10 kW single-phase controller is rated for 15 kW peak backup for 10 seconds.
Pros
- Genuine three-phase backup from one stack
- Near-instant switching with the Gateway
- SolarQuotes reports it can run off-grid when sized appropriately with the Gateway
Cons
- Backup power depends on module count: each 7.8 kWh module supplies only 4 kW
- November 2025 recall of some 8, 10 and 12 kW single-phase controllers over overheating AC plugs
- Owner reviews describe slow warranty support
- Warranty throughput cap applies to all uses
Key specs: 5.2 or 7.8 kWh modules (2.5 or 4 kW each), one to six per controller, IP66.
Price and warranty: About A$8,000 for 13 kWh after the discount, before installation (SolarQuotes, May 2026). 10 years to 70% or about 3 MWh per usable kWh; the Gateway carries 5 years, per SolarQuotes.
Skip it if you need high backup power but plan only one battery module.
Best for Fronius Homes: BYD Battery-Box Premium with GEN24 Plus
A BYD Battery-Box Premium on a Fronius GEN24 Plus gives Fronius support and genuine three-phase Full Backup on the Symo GEN24 Plus 6.0 to 12.0. The catch is the gap: Fronius lists a 10 second switchover for Full Backup, SolarQuotes has reported around 40 seconds with a BYD battery, and our BYD review notes Fronius has said it can take up to 90 seconds.
Pros
- Full Backup supports three-phase loads on larger Symo GEN24 Plus models
- PV Point gives a 3,000 VA outlet from the panels even before a battery is fitted
- BYD works with several inverter brands if you change later
Cons
- Not seamless: clocks reset and computers restart
- Full Backup needs extra switching hardware, and the Symo 3.0 to 5.0 get PV Point only
- Backup runs at 53 Hz, which stops other brands’ AC-coupled inverters helping
- Forum owners report the system may not restart on its own if the battery runs flat in a long outage
Key specs: 22 A battery port (6,200 W on the Primo 6.0 Plus), 3,000 VA PV Point, 53 Hz backup frequency.
Price and warranty: HVM 13.8 about A$8,100 after the discount, plus a GEN24 Plus at A$2,500 to A$4,500 installed. Battery 10 years to 70% or about 3 MWh per kWh; inverter 5 years plus 5 on registration.
Skip it if you need uninterrupted power for a home office or medical device.
Best Budget Essential-Circuit Backup: AlphaESS SMILE-G3
The AlphaESS SMILE-G3 is a low-cost way to keep essentials running. The single-phase S5 supplies up to 5,000 VA of backup, and the three-phase T10 supplies 10,000 VA across all three phases.
Pros
- Cheapest backup-capable all-in-one in this guide on published prices
- Three-phase backup on T models
- Up to 37.2 kWh (S5) for long outages
Cons
- The S5’s 5 kW ceiling does not grow with more modules
- SolarQuotes notes some AlphaESS models have weak surge capacity in blackouts
- SolarQuotes describes AlphaESS warranty support as poor
- Switchover time is not published in what we reviewed
Key specs: 9.3 kWh modules, backup 5,000 VA (S5 and T5) or 10,000 VA (T10), IP65.
Price and warranty: About A$4,600 for 9.6 kWh after the discount, before installation (SolarQuotes, May 2026). 10 years, to 70% or 3.12 MWh per kWh as summarised by SolarQuotes.
Skip it if you want to run ducted air conditioning or a pool pump in an outage.
Best for Long Outages on a Budget: Fox ESS EQ4800
If storms or bushfires cut your power for a day or more, energy matters as much as power. The Fox ESS EQ4800 stacks up to 41.93 kWh at a low price per kWh, on single-phase (H1-G2, KH) or three-phase (H3 Smart, H3 Pro) Fox hybrids.
Pros
- Very large capacity for the money
- Three-phase systems available
- IP65 for outdoor installation
Cons
- Backup power is set by the inverter’s EPS rating, which you must confirm on the quote
- Charges only from 0 °C with no cell heater, a problem for cold-climate recharging
- Owners report about 37.7 kWh measured from a 41.93 kWh stack
- Slow support is a recurring owner complaint
Key specs: 4.66 kWh modules, 9.32 to 41.93 kWh, 50 A maximum battery current, IP65.
Price and warranty: Not published; installer ads vary widely. 10 years (no more than 125 months from manufacture) to 70% or the throughput cap.
Skip it if you are in a frost-prone area or want published backup figures before you buy.
Best for Light Loads in Enphase Homes: Enphase IQ Battery 5P
The Enphase IQ Battery 5P adds backup to Enphase microinverter homes in 5 kWh steps. Each unit supplies 3.84 kVA continuous, and backup needs the IQ System Controller 3 INT.
Pros
- Modular: add units to raise backup power and runtime
- No high-voltage DC battery cabling
- 15-year warranty term
Cons
- One unit runs only light loads; two or three are the realistic minimum for useful backup
- On three phase, each unit gives just 1.28 kVA per phase
- The System Controller adds materially to the price
Key specs: 5.0 kWh, 3.84 kVA, peaks of 26.7 A for 10 s and 33.4 A for 3 s, IP55.
Price and warranty: One unit with the controller was A$8,140 to A$10,140 installed before rebates in a July 2026 guide. 15 years or 6,000 cycles.
Skip it if you want big backup power without buying several units.
Three-phase backup limits
Three-phase homes need extra care, because many batteries back up only part of the house:
- Powerwall 3 backs up one phase only, and Penrith Solar Centre notes phase-imbalance rules can cap a single unit at 5 kW.
- Enphase gives 1.28 kVA per phase per battery.
- Fronius Symo GEN24 Plus 3.0 to 5.0 get PV Point only, not Full Backup.
- SigenStor three-phase, Sungrow SH T and AlphaESS T5 and T10 back up all three phases.
Our single vs three phase guide explains which supply you have.
Two other names to treat carefully. SolarQuotes reports the SolarEdge Home Battery takes about 3 seconds to switch over, with one owner reporting 10 to 20 seconds, and power is capped at 5 kW. Do not buy a new Huawei LUNA2000: Huawei no longer sells batteries here, and SolarQuotes reported its three-phase Backup Box is limited to 3.3 kW per phase.
How we chose
We started from our ten full battery reviews and ranked systems on backup-specific factors: continuous and peak backup power, published switchover time, whole-home versus circuit-level backup, three-phase capability, the ability to recharge from solar in an outage, and price. Warranty terms and support records were tie-breakers. No system was tested in a real outage, and no manufacturer was contacted or paid.
What to check on your quote
- Automatic, not manual. SolarQuotes warned in January 2026 that some installers fit backup that needs a manual switch. Unless there is a technical reason, backup should switch on automatically.
- Backed-up circuits. Get a written list. SolarQuotes notes a typical 5 kW hybrid carries only about 27 A, so it cannot run a 63 A whole-house load.
- Bypass switch. On systems where backup runs through the inverter, a bypass switch should restore mains power to those circuits if the inverter fails.
- Switchover time for your exact model, and whether a UPS is needed for computers.
- Battery power as well as inverter power. The smaller of the two sets your backup kW.
- Recharging in an outage, and whether the system restarts on its own after the battery runs flat.
- The discount. For May to December 2026 it is 6.8 STCs per usable kWh for the first 14 kWh, falling to 5.7 on 1 January 2027. See our battery rebate guide.
Compare quotes line by line with our guide on how to compare solar quotes.
FAQ
Does every solar battery work in a blackout?
No. Solar Victoria says standard systems switch off during an outage, and only systems designed with backup (usually multimode or hybrid) keep supplying the home.
Whole-home or essential circuits?
Whole-home backup needs hardware built for it, such as Sungrow’s 63 A bypass on its 8 and 10 kW models or a Tesla Gateway. On a 5 kW system, back up essentials only, or expect overloads to trip it.
How fast does battery backup switch over?
From under 10 ms (Sungrow SH RS) or 0 ms load-side (SigenStor with Gateway) to 10 seconds or longer (Fronius GEN24 Plus). SolarQuotes says no solar hybrid is a true uninterruptible supply.
Can a home battery run medical equipment?
Solar Victoria advises seeking specialist advice, because home battery systems are typically not appropriate as the primary supply for medical equipment.
How long will my battery last in a blackout?
Divide usable kWh by your load. A 13.5 kWh battery lasts about 1 hour 20 minutes at 10 kW, or most of a night at 1 to 2 kW. Our kW vs kWh explainer shows the maths.
Does joining a VPP affect backup?
It can. Solar Victoria notes VPP systems are designed for market participation and are not customised for backup, so ask how much charge the VPP keeps in reserve. See what a VPP is.
Related guides
- The 8 Best Solar Batteries in Australia for 2026, Compared
- The 7 Best Hybrid Inverters in Australia for 2026
About this guide
Written by the Solar Cobber editorial team. Updated October 2026.
Solar Cobber is a free Australian solar installer directory. We may earn referral or advertising fees from installers, but commercial relationships never affect our picks, and no manufacturer paid for or reviewed this guide. Sources include manufacturer datasheets and warranties, Solar Victoria’s backup power guidance, SolarQuotes’ May 2026 battery prices and January 2026 backup article, and the sources cited in each linked review.
For an installer who designs backup properly, browse our installer directory or read our guide to the best solar battery installers in Australia.