Professional Installation Required
This is a three-phase hybrid inverter operating at PV voltages up to 1000V DC and must be installed by a qualified, MCS-accredited solar PV installer. UK grid-connected installations require G99 approval from the local Distribution Network Operator. The unit must be wall-mounted on a solid brick or concrete surface capable of bearing its weight, in a well-ventilated location away from direct sunlight, with minimum clearances of 300 mm above and below and 100 mm either side.
Battery Compatibility
The H3-12.0-Smart communicates with batteries over CAN bus and supports high-voltage lithium-ion (LFP) battery systems within the 100–800V operating window — including Fox ESS's own HV battery range. Always confirm the specific battery model's compatibility list and minimum module count with your distributor before specifying a system, as this can vary by battery generation.
Three Independent MPP Trackers
3 MPPTs with 1+1+1 string configuration allow panel arrays to be split across three different roof orientations or shading conditions independently. Each tracker handles up to 20 A input current with a 120–950V voltage window, giving flexible array design for larger or more complex roofs.
200% PV Oversize Ratio
Accepts up to 22,500 W of DC input power against a 12,000 W AC rating — a 200% oversize ratio that lets installers fit a larger panel array to maximise generation across the day, particularly valuable on east/west or partially shaded roofs where peak output rarely coincides with the inverter's AC ceiling.
Wide Battery Voltage Window — 100–800V
The 100–800V DC battery input range is a significant step up from the outgoing H3 range, allowing systems to be built with as few as two battery modules instead of a three-module minimum — reducing entry cost for smaller storage installations while still supporting large multi-module HV battery banks.
Fast, True Three-Phase Backup
In an outage, the EPS (backup) circuit switches in under 20 milliseconds, delivering up to 12,000 VA continuous and 14,400 VA peak apparent power (60 seconds) split evenly or unevenly across all three phases, keeping critical circuits powered through a grid failure.
Remote Monitoring with FoxCloud 2.0
Built-in WiFi + LAN + Bluetooth communication (plus optional 4G) links the inverter to the FoxCloud 2.0 platform and smartphone app, with an AI assistant to help interpret system performance and flag issues. Ethernet, RS485, CAN and SG-Ready interfaces support integration with third-party energy management systems.
High Efficiency, IP65 Outdoor Rating
Delivers up to 97.9% maximum efficiency and 97.2% Euro-efficiency, with 99.9% MPPT tracking efficiency minimising conversion losses. The IP65-rated enclosure and fan-assisted cooling allow confident outdoor wall-mounted installation across the full −25°C to +60°C operating range (derated above 45°C).
Inverter & Mounting
1 × H3 Smart inverter with integrated DC switch, 1 × wall-mounting bracket, 3 × hexagonal screws, 6 × expansion tubes and 6 × expansion screws for fixing the bracket to a solid wall.
PV Connectors
PV connectors (3 × positive, 3 × negative) and matching PV pin contacts (3 × positive, 3 × negative) for terminating up to three MPPT input strings.
Battery Connectors
Battery connectors (1 × positive, 1 × negative) with matching battery pin contacts (1 × positive, 1 × negative) for the CAN-communicating LFP battery input.
AC & Communication
1 × AC connector, 1 × communication connector, and 4 × Ethernet cable terminals for grid, EPS and data connections.
Metering & Networking
1 × three-phase smart meter (<80A, DTSU666 compatible) for export limitation and self-consumption monitoring, plus 1 × antenna for WiFi/Bluetooth connectivity.
Earthing & Documentation
1 × earth terminal for protective earth connection, and a quick installation guide. Full technical documentation is available from Fox ESS.
Identification
Manufacturer Model
H3-12.0-Smart
Manufacturer
FOXESS Co., Ltd.
Type
Three-Phase Hybrid/AC Inverter
PV Input
Max. Array Power
24,000 Wp
Max. DC Input Power
22,500 W
Max. DC Voltage
1,000 V (950V max. operating for 1000V system)
Nominal DC Operating Voltage
620 V
MPPT Voltage Range
120–950 V
MPPT Voltage Range (Full Load)
210–850 V
Max. MPPT Input Current
20 / 20 / 20 A
Max. MPPT Short-Circuit Current
25 / 25 / 25 A
Strings per MPP Tracker
1+1+1
Battery
Battery Type
Lithium-Ion battery (LFP)
Battery Voltage Range
100–800 V
Min. Operating Battery Voltage
100 V
Full AC Load Battery Voltage
250 V
Max. Charge/Discharge Current
50.0 A
Communication Interface
CAN
AC Output / Input
Nominal AC Power
12,000 W
Max. Apparent AC Power (Output)
13,200 VA
Max. AC Power (Input/Charging)
14,400 VA
Rated Grid Voltage
400/230V; 380/220V, 3L/N/PE
Rated Grid Frequency
50/60 Hz, ±5 Hz
Rated AC Current (Per Phase)
18.2 A
Max. AC Current (Per Phase)
20.0 A (up to 22.7 A with expansion function enabled remotely)
Power Factor
1 (adjustable 0.8 leading to 0.8 lagging)
EPS (Backup) Output
Max. Apparent AC Power
12,000 VA
Peak Apparent AC Power (60s)
14,400 VA
Rated Output Voltage
400/230V AC, 3L/N/PE
EPS Max. Current (Per Phase)
17.4 A
Max. Balanced Output per Phase
4,000 W (1/3 of rated power)
Efficiency
Protection
PV Reverse Polarity Protection
Yes
Battery Reverse Protection
Yes
Anti-Islanding Protection
Yes
Output Short-Circuit Protection
Yes
Leakage Current Protection
Yes
Insulation Resistor Detection
Yes
Overvoltage Category
III (AC side), II (DC side)
DC/AC Surge Protection
Type II (PV) / Type II (AC)
General Data
Dimensions (W×H×D)
600 × 450 × 226 mm
Installation
Wall-mounted
Operating Temperature Range
−25°C to +60°C (derating above 45°C)
Storage Temperature
−40°C to +70°C
Storage/Operating Humidity
0–100%
Max. Altitude
4,000 m (derating above 2,000 m)
Ingress Protection
IP65 (for outdoor use)
Standby Consumption
20–25 W
Inverter Topology
Non-isolated
Communication Interfaces
Ethernet, EMS (RS485), Meter, WiFi+LAN+Bluetooth, 4G (optional), DRM, Ripple Control, USB, BMS (CAN), SG-Ready
Display
Backlit 16×4 character LCD
Buttons
Capacitive touch sensor × 4
Parallel Operation
Up to 10 units (on-grid systems)
What comes in the box with the Fox ESS H3-12.0-Smart?
Per the official Fox ESS installation manual, the standard packing list includes: 1 × H3 Smart inverter, 1 × wall-mounting bracket, 3 × hexagonal screws, 6 × expansion tubes and 6 × expansion screws, PV connectors and pin contacts (3 positive, 3 negative each), battery connectors and pin contacts (1 positive, 1 negative each), 1 × AC connector, 1 × communication connector, 4 × Ethernet cable terminals, 1 × three-phase smart meter (<80A), 1 × antenna, 1 × earth terminal, and a quick installation guide. Always check the delivered items against this list immediately on unboxing and report any shortages before installation begins.
How many battery modules does the H3-12.0-Smart need at minimum?
With a 100–800V battery voltage range, the H3 Smart series can typically operate with as few as two battery modules, depending on the specific battery model's individual module voltage. This is an improvement over the outgoing H3 range's ECS/EQ batteries, which generally required a three-module minimum. Always confirm minimum and maximum module counts for your chosen battery against the manufacturer's current compatibility documentation before finalising a system design.
Does this inverter support three-phase backup during a power cut?
Yes. The H3-12.0-Smart provides true three-phase EPS (backup) output, switching in under 20 milliseconds when the grid is lost, with battery required for EPS operation. It delivers up to 12,000 VA continuous and 14,400 VA peak (60 seconds), distributable across the three phases either evenly or, when correctly wired to the smart meter, according to actual per-phase load.
What is the maximum PV array size I can connect?
The inverter accepts up to 22,500 W of maximum DC input power across its 3 MPP trackers, against a 24,000 Wp maximum array power rating — a 200% PV oversize ratio relative to the 12,000 W AC output. This lets installers fit a generously sized panel array, which is particularly useful for maximising energy harvest from east/west-facing or partially shaded roofs.
Can multiple H3-12.0-Smart units be installed together?
Yes. The H3 Smart series supports parallel operation of up to 10 units for on-grid systems (up to 4 units for off-grid/EPS-only configurations), enabling scalable systems well beyond a single unit's 12kW rating for larger commercial installations. Parallel systems require matched inverter models and firmware versions, and specific cabling and communication wiring — refer to the manufacturer's parallel installation instructions.
What UK compliance and grid approval does this inverter need?
As a grid-connected three-phase inverter, the H3-12.0-Smart must be installed by an installer able to certify compliance with G99 for UK grid connection, and the installation should be carried out by an MCS-accredited installer if the system is to qualify for relevant UK incentive schemes. The DNO (Distribution Network Operator) must be notified or approval obtained before commissioning, in line with standard UK solar PV and battery storage installation practice.
