Battery brands and comparisons

Fox ESS vs Alpha ESS: which home battery suits your home? (2026)

Guides · Homerise team · Reviewed by Joern Haake · Published 5 November 2026 · Rebate figures verified 22 October 2026 · How we write guides

The short answer

Both are on the approved list for the federal battery rebate, both come in single- and three-phase versions, and both have a way to add a battery to existing solar. The main differences: Fox ESS builds large stacks from small high-voltage modules for its own hybrid inverters, with three-phase inverters up to 29.9 kW; Alpha ESS sells SMILE systems with larger modules. Alpha ESS is on 5 of the 5 VPP lists we checked and Fox ESS on 4; in WA, their standing on Synergy's list differs (below). The rebate is the same for the same usable size: about $3,663 on 15 kWh if installed now. Facts from each maker's Australian datasheets and warranty, checked 15 October 2026.

How do Fox ESS and Alpha ESS compare?

Fox ESS vs Alpha ESS SMILE (manufacturers' Australian datasheets and warranties, checked 15 October 2026)
	Fox ESS	Alpha ESS SMILE
What it is	High-voltage batteries for Fox ESS hybrid inverters (H1 G2 and KH single-phase, H3 three-phase), and the Power Cube, an all-in-one with the inverter and battery modules together.	SMILE systems in hybrid versions (for new solar) and AC-coupled versions (for existing solar), single- and three-phase.
Sizes	EQ4800: 9.3 to 41.9 kWh in 4.66 kWh modules. EQ5500: 10.9 to 49.1 kWh in 5.46 kWh modules. EP11 and EP12 Plus: 10.4 and 11.5 kWh units, up to 4 in parallel.	SMILE-G3: 9.3 kWh modules, 9.3 to 37.2 kWh single-phase and up to 55.8 kWh three-phase. SMILE-M5/M10: 13.99 kWh modules, 14 to 28 kWh. SMILE5: modules of 13.3 or 15 kWh, up to about 75 to 80 kWh.
Modules	EQ4800 4.66 kWh, EQ5500 5.46 kWh, EP11 10.36 kWh, EP12 Plus 11.52 kWh	9.3, 13.99, 13.3 and 15 kWh modules depending on the series
Phases	Single-phase H1 G2 (3–6 kW) and KH (7–10.5 kW); three-phase H3 Smart (5–15 kW) and H3 Pro (15–29.9 kW). Power Cube PQ1 single-phase (5–12 kW) and PQ3 three-phase (5–15 kW).	Single-phase 5 kW (G3-S5, M5, SMILE5) and 8–10 kW (M10); three-phase G3-T5 to T20.
Power	Set by the inverter; the EQ stacks themselves run from about 4.5 kW (2 modules) to 20 kW (9 modules).	About 5 kW on the single-phase 5 kW models; up to 20 kW of backup on the three-phase G3.
Backup	The inverters back up to their rated power; the Power Cube has a built-in 63 A bypass for whole-home backup, and three-phase H3 systems use the separate EPS Box Pro.	UPS-style backup: under 10 ms switch-over on the three-phase G3 and under 20 ms on the M series.
Existing solar	For homes with solar already, Fox sells the AC1 G2, an AC-coupled battery inverter (3 to 6 kW).	AC-coupled versions (SMILE-G3-B5, and the M5-B) add a battery to existing solar.
Build	LFP, IP65 (EQ and EP batteries), indoor or outdoor; charges from 0 °C and discharges from −10 °C, up to 55 °C.	LFP, IP65, outdoor; aerosol fire suppression in the G3 and M series.
Warranty	10 years; at least 70% of capacity at 10 years or a throughput limit, whichever comes first.	10 years; at least 70% of usable capacity over 120 months, with a throughput limit of about 3.12 MWh per kWh.
VPPs listing it	4 of the 5 we checked	5 of the 5 we checked
Western Australia	On Synergy's list as provisional (not yet ready for its VPP) on 1 October 2026.	On Synergy's Supported Solutions List as ready for its VPP (a green tick) on 1 October 2026, which matters for WA's battery scheme.
Approved list	The EQ4800, EQ5500, EP11 and EP12 Plus are on the Clean Energy Council approved list.	SMILE batteries are on the Clean Energy Council approved list.
Supplied in Australia by	FoxESS Australia Pty Ltd (Springvale, VIC)	Alpha ESS Australia Pty Ltd (Homebush West, NSW), in Australia since 2015

Which has the better warranty for your use?

Both run 10 years to 70% of capacity, with a throughput limit. The conditions are where they differ:

Fox ESS: 10 years; at least 70% of capacity at 10 years or a throughput limit, whichever comes first. Throughput limit: about 4.2 MWh per kWh for the EQ batteries and about 3.7 MWh per kWh for the EP batteries. The battery must be registered and connected to Fox's warranty portal when it's commissioned. Claims go through your installer. (Fox ESS HV Battery Warranty Policy (Australia and NZ), V2.7, 28 March 2026)
Alpha ESS: 10 years; at least 70% of usable capacity over 120 months, with a throughput limit of about 3.12 MWh per kWh. It covers self-consumption, time-of-use, backup and VPP operation. It needs an internet connection, an SAA-accredited installer with an Alpha installer ID, and an ambient temperature of −10 to 50 °C out of direct sun. It transfers with the building. (Alpha ESS Residential Product Series warranty conditions (Australia), 15 June 2026)

Warranty terms change; the version that applies is the one on the day your battery is installed.

Which VPPs take each?

On each VPP's own list (checked 15 October 2026)
VPP	Fox ESS	Alpha ESS
Amber SmartShift	Beta	Yes
AGL VPP	Not listed	Yes
Origin (Loop)	Yes	Yes
ENGIE VPP	Yes	Yes
GloBird ZEROHERO VPP	Yes	Yes

Amber SmartShift supports the H1 G2, KH and H3 Smart in beta.
Origin lists the H1, AC1, KH, KA and H3 inverters with the EQ4800, EP5, EP11, CQ6 and CQ7 batteries.
Amber supports Alpha ESS systems with serial numbers starting "AL".
Alpha says the SMILE5, SMILE-G3 and SMILE-T10-HV are eligible for the NSW VPP incentive.

VPP lists change often, so check with the provider before you choose. What VPPs pay and the trade-offs: virtual power plants.

Which works better in Western Australia?

WA's battery scheme is tied to joining a VPP, so Synergy's Supported Solutions List matters there. Fox ESS: On Synergy's list as provisional (not yet ready for its VPP) on 1 October 2026. Alpha ESS: On Synergy's Supported Solutions List as ready for its VPP (a green tick) on 1 October 2026, which matters for WA's battery scheme. See rebates in Western Australia.

Adding a battery to existing solar

Fox ESS: For homes with solar already, Fox sells the AC1 G2, an AC-coupled battery inverter (3 to 6 kW).
Alpha ESS: AC-coupled versions (SMILE-G3-B5, and the M5-B) add a battery to existing solar.

See adding a battery to existing solar.

Which suits your home?

Fox ESS tends to suit:

Large batteries from small modules: EQ stacks reach about 42 to 49 kWh
Three-phase homes, with inverters up to 29.9 kW
Adding a battery to existing solar with Fox's AC-coupled inverter
Joining Origin, ENGIE or GloBird's VPPs

Alpha ESS tends to suit:

Sizing to the rebate tiers: the M series' 13.99 kWh modules match the 14 and 28 kWh steps
Joining a VPP: on every main list we checked, and VPP-ready on Synergy's list in WA
Adding a battery to existing solar (AC-coupled versions)

What to check with either:

Fox ESS: Registration on Fox's warranty portal at commissioning
Fox ESS: Which inverter caps your battery power
Fox ESS: AGL's VPP didn't list Fox ESS when we checked
Alpha ESS: Battery power on the single-phase 5 kW models is lower than on larger hybrids
Alpha ESS: The warranty's internet and temperature conditions

The rebate and the price

The federal battery rebate is the same for every approved brand of the same usable size: about $3,663 on 15 kWh if installed now. It pays the full rate on the first 14 kWh and less on each kWh above, so module sizes that land near that step can matter. The price depends more on the size, the inverter and your home than on the badge: most homes pay about $700 to $850 per kWh installed after the rebate (October 2026). See solar battery cost. More on each: Fox ESS EQ and EP batteries, and the Power Cube · Alpha ESS SMILE batteries · seven home batteries compared.

Questions people ask

Is Fox ESS better than Alpha ESS?

Neither is better for every home. Fox ESS builds large stacks from small modules for its own hybrid inverters, with three-phase inverters up to 29.9 kW; Alpha ESS sells SMILE systems with larger modules. Choose on phases, the size you need, existing solar, the VPP you want and the warranty conditions.

Which has the better warranty, Fox ESS or Alpha ESS?

Both run 10 years to 70% capacity with a throughput limit. Fox ESS: Throughput limit: about 4.2 MWh per kWh for the EQ batteries and about 3.7 MWh per kWh for the EP batteries. Alpha ESS: 10 years; at least 70% of usable capacity over 120 months, with a throughput limit of about 3.12 MWh per kWh. It needs an internet connection, an SAA-accredited installer with an Alpha installer ID, and an ambient temperature of −10 to 50 °C out of direct sun.

Do Fox ESS and Alpha ESS get the battery rebate?

Yes, both are on the Clean Energy Council approved list. The rebate depends on the usable size and the installation date, not the brand: about $3,663 on 15 kWh if installed now.

Do Fox ESS and Alpha ESS work with Amber?

On Amber SmartShift's own list (checked 15 October 2026), Fox ESS is listed in beta and Alpha ESS listed. Amber SmartShift supports the H1 G2, KH and H3 Smart in beta. Amber supports Alpha ESS systems with serial numbers starting "AL".

Which virtual power plants work with Fox ESS and Alpha ESS?

On each provider's own list (checked 15 October 2026): Fox ESS is listed by Origin (Loop), ENGIE VPP and GloBird ZEROHERO VPP, in beta by Amber SmartShift; Alpha ESS by Amber SmartShift, AGL VPP, Origin (Loop), ENGIE VPP and GloBird ZEROHERO VPP. In WA: Fox ESS, on Synergy's list as provisional (not yet ready for its VPP) on 1 October 2026. Alpha ESS, on Synergy's Supported Solutions List as ready for its VPP (a green tick) on 1 October 2026, which matters for WA's battery scheme.

Sources

General information, not financial advice. Rebate rules change: figures on this page come from our rules table, last verified 22 October 2026. How we're paid: installers pay Homerise for introducing you. No brand or installer pays to be mentioned in a guide.