FOXESS H3 Smart: the three-phase hybrid in 5, 9.9 and 15 kW

Quick answer: the FOXESS H3 Smart is a three-phase hybrid inverter, and we install the 5 kW (H3-5.0-Smart), 9.9 kW (H3-9.9-Smart) and 15 kW (H3-15.0-Smart) models. All three have three MPPTs rated at 20 A, accept up to 11, 20 or 30 kWp of panels, work with high-voltage batteries from 100 to 800 V and switch to backup in under 20 ms. It suits homes with three-phase supply, and we pair it with a 27.84 or 41.76 kWh CQ7 battery.

The FOXESS H3 Smart range runs from 5 kW to 15 kW, and the series has been on the Clean Energy Council’s approved inverter list since July 2025. We install three sizes that span a modest three-phase roof to a very large one. If you are not sure whether your home has three-phase supply, check that first: our guide to single phase vs three phase solar explains how.

FOXESS H3 Smart models compared

All figures are from FOXESS’s Australian H3 Smart datasheet.

All three share the same case and these ratings:

• Solar inputs: three MPPTs, one string each, 20 A per input (25 A short-circuit) and up to 10,000 W per input; 120 to 950 V operating range, 1,000 V maximum.
• Battery port: 100 to 800 V.
• Backup: EPS switchover in under 20 ms.
• Efficiency: 97.20% European weighted.
• Build: 600 × 450 × 226 mm, 34 kg, wall mounted, IP65, with a DC switch and optional arc-fault detection (AFCI); rated from −25 to +60 °C, derating from 45 °C.

Who needs a three-phase hybrid?

A three-phase inverter connects to all three phases of your supply. If your home has three-phase power, it is usually the better fit for a large system, because Victorian distributors generally allow more inverter capacity and more export on three-phase connections. United Energy, for example, allows up to 15 kW of export on three phase, against 5 kW on single phase.

The three sizes map to roof size more than house size. The 5 kW model suits a three-phase home with room for up to 11 kWp of panels. The 9.9 kW model takes up to 20 kWp, and the 15 kW model up to 30 kWp, for a large roof and heavy daytime loads such as an EV charger, pool equipment or electric heating.

Solar inputs: three MPPTs at 20 A

Each of the three MPPTs (maximum power point trackers) runs one string of panels at its own best operating point, so the H3 Smart handles up to three roof orientations well. Two details suit large modern panels: each input takes up to 20 A, more than the 16 A on FOXESS’s single-phase inverters, and the 1,000 V maximum allows longer strings than a 600 V inverter.

The 5 kW model accepts up to 11 kWp of panels, 220% of its rating and the highest ratio of any inverter we install. The 15 kW model takes up to 30 kWp, but it can take in at most 22.5 kW of solar power at any moment, so on a large north-facing array the peak above that is clipped around midday on the clearest days.

Three-phase metering: a smart meter and six CTs

A hybrid inverter has to see what the house is importing and exporting to decide when to charge, discharge and limit export. On single phase, two clamp-on current transformers (CTs) do that. On three phase every phase needs measuring, so the H3 Smart kits we install include a three-phase smart meter with six CTs: three at the grid connection, one on each phase, and three on an existing solar inverter if you are keeping one.

FOXESS’s three-phase meter, the DTSU666, comes with six 100 A CTs on 10 m leads and communicates with the inverter over RS485. Measuring an existing inverter is what lets an H3 Smart add a battery to a home that already has three-phase solar.

Battery: CQ7 stacks of up to 12 modules

The H3 Smart’s battery port spans 100 to 800 V, the widest of the FOXESS inverters we install, and FOXESS’s compatibility list allows one CQ7 stack per H3 Smart of up to 12 modules (83.52 kWh), against six on the single-phase H1 G2 and KH.

Our packages use four modules (27.84 kWh) or six (41.76 kWh), all of it usable; the 5 kW model comes with the four-module stack. A larger battery isn’t automatically better, so size it on your evening and overnight use. The CQ7 battery guide compares the two stacks and explains how they are built.

Backup on three phase

The H3 Smart’s EPS (emergency power supply) output switches over in under 20 ms, and its rating depends on the model. As with FOXESS’s single-phase inverters, the EPS output feeds a dedicated backed-up circuit wired by your electrician. Backing up the whole switchboard takes extra switching equipment. Our guide to FOXESS backup explains the difference and what to put on a backed-up circuit.

Our H3 Smart packages

Each package includes the inverter, a CQ7 stack, the three-phase meter and CTs, and a backed-up circuit; panels and mounting are quoted after a site assessment.

• FOXESS H3 Smart 5 kW three-phase system with 27.84 kWh, for up to 11 kWp of panels
• H3 Smart 9.9 kW system with 27.84 kWh or the H3 Smart 9.9 kW system with 41.76 kWh, for up to 20 kWp
• H3 Smart 15 kW system with 27.84 kWh or the H3 Smart 15 kW system with 41.76 kWh, for up to 30 kWp

The FOXESS battery systems guide sets the H3 Smart beside the single-phase range, and Build Your System recommends a size from your bill, your phase and your backup needs.

Frequently asked questions

What sizes does the FOXESS H3 Smart come in?

FOXESS makes the H3 Smart in seven sizes from 5 kW to 15 kW: 5.0, 6.0, 8.0, 9.9, 10.0, 12.0 and 15.0 kW. We install the 5, 9.9 and 15 kW models, which accept up to 11, 20 and 30 kWp of solar panels respectively when a battery is part of the system.

Can the FOXESS H3 Smart run on a single-phase supply?

No. It is a three-phase inverter and needs a three-phase connection. For single-phase homes, FOXESS’s equivalents in our range are the 5 kW H1 G2 and the 8 kW and 9.9 kW KH models, which pair with the same CQ7 battery and the same FoxCloud app.

What battery works with the FOXESS H3 Smart?

FOXESS’s CQ7 high-voltage battery. The H3 Smart’s battery port runs from 100 to 800 V, and FOXESS’s compatibility list allows one CQ7 stack of up to 12 modules (83.52 kWh). Our packages use four modules (27.84 kWh) or six (41.76 kWh), all of it usable.

Does the FOXESS H3 Smart need a smart meter?

Yes. On three phase it uses a three-phase smart meter, so it can see import and export on every phase. Our H3 Smart kits include a three-phase meter with six CTs: three at the grid connection and three for an existing solar inverter, if you are keeping one.

What warranty does the FOXESS H3 Smart have?

FOXESS covers the H3 Smart for 10 years: 120 months from installation, but no more than 132 months from manufacture. A FoxPro extension can take cover to 240 months in total if taken up within 36 months of commissioning. Cover depends on an accredited installer, and we add our own 5-year workmanship warranty.