Compare 20 kWh home batteries
EcoFlow 19.2 kWh usable and SolaX 18.4 kWh usable side by side
Single-phase · Without backup · Figures from the manufacturers' datasheets, prices from our written quotes.
 |  | |
|---|---|---|
| Installed price, rebate taken off | $9,938 | $8,333Lower |
| Energy you can use | 19.2 kWhRated 20.4 kWhMore | 18.4 kWhRated 20.4 kWh |
| Price per usable kWh | $518 | $454Lower |
| Blackout backup power | 10 kWSwitches over in 0 ms | 10 kWSwitches over in under 10 ms |
| Whole-home backup | Built in | Built in |
| Power it can supply at once | 10 kW | 10 kW |
| Time to fill from the grid | About 2 hoursAt up to 10 kW | About 2 hoursAt up to 10 kW |
| With your existing solar | Works beside your inverterNew panels can connect to it too | Works beside your inverterNew panels can connect to it too |
| Where it can go | Floor onlyIP65 · -20 to 50 °C | Floor onlyIP66 · -30 to +53 °C |
| Inverter noise | Not on the EcoFlow datasheet | Under 35 dB |
| Warranty | 15 yearsKeeps at least 70% of its capacityLonger | 10 yearsKeeps at least 70% of its capacity |
| Add more battery later | Up to 12 modulesUp to 57.6 kWh, any time | Up to 13 modulesUp to 59.7 kWh, within a year of installation |
| Virtual power plants | None listed yet | GloBird |
| Solar panels it can take | 20 kW | 20 kW |
| Size installed | H 2,047 × W 680 × D 203 mmInverter on top, heaviest piece 56 kg, about 259 kg in total | H 957 × W 600 × D 376 mmInverter on the wall 557 × 590 × 180 mm, heaviest piece 47 kg, 211 kg in total |
| View the quoteBook an InspectionQuoted as EcoFlow 20.4 kWh single-phase with 10 kW inverter | View the quoteBook an InspectionQuoted as SolaX 20.4 kWh single-phase with 10 kW inverter | |
Next step
19.2 kWh usable · $9,938
18.4 kWh usable · $8,333
Why prices differ at about 20 kWh
This group has eight single-phase systems from four brands, holding 17.4 to 23 kWh usable. Installed prices run from $7,838 to $9,938 without backup, or $394 to $549 per usable kWh. The lowest price per usable kWh here, SolaX 23 kWh usable at $394, has a 5 kW inverter that takes solar panels up to 10 kW. Most systems here have 10 kW inverters that take up to 20 kW. Backup is extra on every system. Partial backup adds $500 on EcoFlow, GoodWe and SolaX and $1,456 on Sigenergy, which includes a Sigen Gateway. The batteries supply less than the inverter on two systems here: GoodWe 17.4 kWh usable with the 10 kW inverter (up to 9 kW) and Sigenergy 18 kWh usable with the 10 kW inverter (up to 9.2 kW).
This group has 10 three-phase systems from five brands, holding 17.4 to 24.1 kWh usable. Installed prices run from $7,567 to $12,236 without backup, or $435 to $614 per usable kWh. Backup is extra on every system. Partial backup adds $500 on Anker SOLIX, EcoFlow, GoodWe and SolaX and $1,681 on Sigenergy, which includes a Sigen Gateway. On five systems here the batteries supply less power on their own than the inverter. Their rows say so.
Every system here uses LFP battery cells, with batteries and inverters rated IP65 or IP66, and a battery warranty that keeps at least 70% of capacity at the end of its term.
What changes at about 20 kWh
The federal battery rebate (Cheaper Home Batteries Program) is worked out on usable energy, at a rate of $252 per kWh on the quote date: 100% of the rate for the first 14 kWh, 60% of the rate for 14 to 28 kWh, 15% of the rate for 28 to 50 kWh. In this group it comes to $4,033 to $5,032 per system, or $209 to $232 per usable kWh, less per kWh than on smaller systems. The rebate is set by the installation date, and eligibility is confirmed before installation.
Going one size up with the same brand, supply and inverter adds $1,016 to $3,909 from this group, or $183 to $345 for each extra kWh of usable energy.
Each step up (14)
| System | From | To | Adds | Per extra kWh |
|---|---|---|---|---|
| Anker SOLIX, three-phase, 10 kW inverter | 20 kWh usable | 25 kWh usable | $1,622 | $324 |
| EcoFlow, single-phase, 10 kW inverter | 19.2 kWh usable | 28.8 kWh usable | $2,839 | $296 |
| EcoFlow, three-phase, 10 kW inverter | 19.2 kWh usable | 24 kWh usable | $1,240 | $258 |
| EcoFlow, three-phase, 12 kW inverter | 24.1 kWh usable | 32.1 kWh usable | $2,769 | $345 |
| GoodWe, single-phase, 10 kW inverter | 17.4 kWh usable | 26.1 kWh usable | $1,595 | $183 |
| GoodWe, three-phase, 10 kW inverter | 17.4 kWh usable | 26.1 kWh usable | $2,015 | $232 |
| GoodWe, three-phase, 15 kW inverter | 17.4 kWh usable | 26.1 kWh usable | $1,703 | $196 |
| Sigenergy, single-phase, 10 kW inverter | 18 kWh usable | 27 kWh usable | $1,835 | $204 |
| Sigenergy, three-phase, 10 kW inverter | 18 kWh usable | 27 kWh usable | $1,862 | $207 |
| Sigenergy, three-phase, 15 kW inverter | 18 kWh usable | 27 kWh usable | $1,705 | $189 |
| SolaX, single-phase, 5 kW inverter | 18.4 kWh usable | 23 kWh usable | $1,016 | $221 |
| SolaX, single-phase, 10 kW inverter | 18.4 kWh usable | 23 kWh usable | $1,556 | $339 |
| SolaX, single-phase, 10 kW inverter | 23 kWh usable | 27.5 kWh usable | $1,143 | $249 |
| SolaX, three-phase, 15 kW inverter | 23 kWh usable | 36.7 kWh usable | $3,909 | $284 |
Packages are named by their rated size. We group them by usable energy, so EcoFlow 25.5 kWh (24 kWh usable) and SolaX 25.5 kWh (23 kWh usable) are in this group.
How we compare
Prices come from Sunbridge Energy's written quotes, issued 20 October 2026 and valid until 19 November 2026. Each includes GST, the listed equipment and standard installation and commissioning, with the federal battery rebate (Cheaper Home Batteries Program) deducted at the rate for an installation on the quote date. The rebate is set by the installation date, and eligibility is confirmed before installation. Prices are the same in NSW, VIC and QLD.
These options and site work can add to a price, and each written quote sets them out: garage installation +$500, new concrete slab +$250, cable beyond 5 m +$30 per metre, remove old inverter +$300, remove old battery +$600, remove old inverter and battery +$900 and switchboard upgrade up to $1,500.
Specifications come from the manufacturers' datasheets for each battery module and inverter. Where a datasheet we hold leaves a figure out, we say so rather than estimate it. For 32 of the 62 systems, the inverter datasheet gives no separate limit for power drawn from the battery, so we show the inverter's output and, where it is lower, the batteries' own rating instead of a combined figure. Price per usable kWh and warranty energy are calculated by Sunbridge from these figures.
We only compare systems built for the same supply, and we group sizes by usable energy. Brand comparisons pair systems with usable energy within 10% and the same inverter output, and say so when they can't. A figure counts as different only when the gap is large enough to matter: $100 of price, $10 per usable kWh, 0.5 kWh of usable energy, 0.5 kW of inverter output, 1 kW of solar input, one year of warranty, 5% of warranty energy or 5 kg of weight.
We supply and install every system on this page and earn from each installation, so this is not an independent review. We only list the six brands we install. Brands we don't install, such as Tesla, Sungrow and BYD, are not here.
Questions about home batteries of about 20 kWh
How much does a home battery of about 20 kWh cost installed?
We install 18 systems with 15 to 25 kWh of usable energy. Single-phase systems cost $7,838 to $9,938 and three-phase systems $7,567 to $12,236, including GST and standard installation, after the federal battery rebate and without backup. Each links to its written quote, valid until 19 November 2026.
Which battery of about 20 kWh is best?
No single system is best for every home. Among single-phase systems here, GoodWe 17.4 kWh usable has the lowest installed price ($7,838, with a 10 kW inverter) and SolaX 23 kWh usable has the lowest price per usable kWh ($394). Among three-phase systems, GoodWe 17.4 kWh usable has the lowest installed price ($7,567, with a 10 kW inverter). Compare inverter size, solar input and warranty too, which the list above shows.
Why do systems of about 20 kWh differ so much in price?
Price per usable kWh runs from $394 to $549 for single-phase systems and $435 to $614 for three-phase systems. Among single-phase systems, the lowest, SolaX 23 kWh usable at $394, has a 5 kW inverter that takes solar panels up to 10 kW, while most have 10 kW inverters that take up to 20 kW. Backup is extra on every system. Partial backup adds $500 on EcoFlow, GoodWe and SolaX and $1,456 on Sigenergy, which includes a Sigen Gateway.
Why is the rebate per kWh lower on bigger batteries?
The federal battery rebate (Cheaper Home Batteries Program) is worked out on usable energy, at a rate of $252 per kWh on the quote date: 100% of the rate for the first 14 kWh, 60% of the rate for 14 to 28 kWh, 15% of the rate for 28 to 50 kWh. In this group it comes to $4,033 to $5,032 per system, or $209 to $232 per usable kWh, less per kWh than on smaller systems. The rebate is set by the installation date, and eligibility is confirmed before installation.
Is about 20 kWh the right size for my home?
Look at how much electricity you use between about 4pm and 7am, in your retailer's app or on your bill. A battery's usable energy is what it can supply over that time. We work through the size with you at the inspection.
Which brands have systems of about 20 kWh?
Five: Anker SOLIX, EcoFlow, GoodWe, Sigenergy and SolaX. The ESY systems we install are all larger.
More comparisons
What happens when you book
Choose a time and the inspection goes straight into your local branch's calendar. It takes about 20 minutes. We confirm your supply, where the system goes and whether anything changes the price, before anything is final.
Sunbridge Energy supplies and installs every system here through its Sydney, Melbourne, Brisbane and Gold Coast branches. Sigenergy Certified Installer · GoodWe Verified Installer, installer code G10000622 · New Energy Tech Consumer Code Approved Seller.