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Fox ESS H3 Plus 125kW 3PH Hybrid Inverter
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Fox ESS H3 Plus 125kW 3PH Hybrid Inverter

FE-H3-PLUS-125.0
£8,378.54 ex VAT £10,054.25 inc VAT

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High Conversion EfficiencyMore of your solar reaches the home
MPPT TrackingMaximises yield in changing light
Grid CompliantMeets UK G98 / G99 requirements
Technical Specifications
Rated Power (Pmax)125 kW
Module Efficiency98.5 %
Battery Voltage180 - 950 V
MPPT Quantity8
Min MPPT Voltage180 V
Max MPPT Voltage850 V
Max Input Voltage1,000 V
Max DC Power250 kW
Max AC Power (5 min)137.5 kVA
Max DC Current40 A
Max DC Inputs16
Integrated DC SwitchYes
Height1060 mm
Width730 mm
Depth305 mm
Weight120 kg
IP RatingIP65
Operating Temperature-30 °C to +60 °C
Warranty5 years standard, 10 years when the installation is registered with Fox ESS online
View Full Datasheet

Fox ESS H3 Plus 125kW 3PH Hybrid Inverter

Fox ESS · H3 Plus

Fox ESS H3 Plus 125kW 3PH Hybrid Inverter

Fox ESS H3 Plus — 50 kW to 125 kW with three battery ports, 240 A of battery current and DC-link EV charging.

The H3 Plus is Fox's commercial and industrial storage platform. Fifty to 125 kW of three-phase output, up to 250 kW of PV, and three battery ports rated 80 A each — 240 A combined, which is an order of magnitude beyond a domestic hybrid.

Rated AC output
125 kWThree phase on-grid output
Backup output
137.5 kVAContinuous EPS power in a grid outage
Maximum PV input
250 kWArray size this inverter accepts
Battery window
180 – 950 VThe architecture it takes
MPP trackers
8Independent roof planes
Peak efficiency
98.5 %Conversion efficiency at best
Backup switch time
<10 msHow fast it takes over
Warranty
5 yearsStandard, 10 years when the installation is registered with Fox ESS online
Overview

About the Fox ESS H3 Plus

Two features mark it out at this scale. The AC input accepts 207 kVA with a 300 A bypass, so the system can pass grid power through to the load at full site current while charging. And it is DC-link EV charger ready from 20 to 50 kW, meaning a DC fast charger can be fed straight from the battery bus without a second conversion.

Efficiency is 98.5 % peak and 98.1 % European, with AFCI, string current detection and terminal overtemperature protection all fitted as standard rather than optional.

Battery compatibility

Which battery does this inverter take?

This inverter takes High voltage Fox ESS stacks.

This model has a battery voltage window of 180 – 950 V, BMS communication over CAN × 3.

A stack is one master module, which carries the BMS, plus matching slave modules of the same type. Module types are never mixed in one stack. These are the counts this inverter is listed for — Product Compatibility Fox ESS UK 2026, the module count range for this inverter family:

Battery modules this inverter accepts
CQ74 to 42 modules — 28.08 to 294.84 kWh
CQ164 to 45 modules — 64.28 to 723.15 kWh

What we stock that fits this inverter:

Fox ESS CQ7 Master Promo Stock Only4 to 42 modules on this inverter, 28.1 to 294.8 kWh.
Fox ESS CQ16 (16.07kWh) High Voltage Storage Battery for H3 Plus Range4 to 45 modules on this inverter, 64.3 to 723.1 kWh.
Fox high-voltage modules are not mixed: a stack is one type, one master and the matching slaves, and the module count must sit inside the range above for this inverter. A Fox low-voltage battery (LV52) will not work on any of these inverters, and a high-voltage stack will not work on a low-voltage one.
For the installer

String design, battery limits and what is in the box

The details that decide whether this unit suits the job:

  • Three battery ports, 80 A each, 240 A combined, 180 – 950 V, three CAN channels.
  • Four MPP trackers on the 50 and 60 kW, eight from the 75 kW up. Two strings per tracker, 40 A per tracker, 50 A Isc.
  • 1,000 V withstand, 180 – 950 V input range, 180 – 850 V MPPT window, 180 V start-up.
  • AC input 207 kVA maximum with a 300 A bypass current and 300 A LRA on the EPS output.
  • AFCI, string current detection, ISO detection, residual current and ground fault detection and terminal overtemperature protection all fitted as standard.
  • DC-link EV charger ready, 20 to 50 kW.
  • 730 × 1,060 × 305 mm, 115 to 120 kg. Smart air cooling, under 70 dB, IP65, rated from −30 °C.
  • Standby consumption under 60 W.
Applications

Where this hybrid earns its place

The H3 Plus is specified most often for these jobs.

Industrial peak shaving240 A of battery current across three ports.
Commercial microgrids155 kVA peak EPS for 10 seconds with a 300 A bypass.
Sites with DC fast chargingDC-link EV charger ready from 20 to 50 kW.
Large PV plus storageUp to 250 kW of PV on a 125 kW inverter.
Grid services and arbitrage207 kVA AC input for fast grid charging.
Cold and exposed sitesRated from −30 °C, IP65, smart air cooling.
Before you order

Things worth knowing about this listing

These notes come from us and from the manufacturer, and they are the ones that most often cause a problem after delivery:
  • Register the installation with Fox ESS at fox-ess.com to activate the 10-year warranty. Unregistered, the cover is 5 years.
Technical specification

Fox ESS H3-125-Plus technical data

This model
Maximum PV array power250 kW
Maximum PV input power250 kW
Number of MPP trackers8
Output, backup and performance
Rated AC output power125 kW
Maximum apparent AC power137.5 kVA
Rated AC output current189.9 A
Maximum AC output current198.5 A
Backup (EPS) continuous power137.5 kVA
Weight120 kg
Common to the range
Withstand voltage1,000 V
Input voltage range180 – 950 V
Maximum MPPT input current40 A
Maximum MPPT short circuit current50 A
MPPT voltage range180 – 850 V
Start-up voltage180 V
Strings per MPP tracker2
Battery typeLFP (LiFePO₄)
Battery voltage range180 – 950 V
Maximum charging / discharging current240 A (80 + 80 + 80)
Battery ports3
Battery communicationCAN × 3
Nominal AC voltage380/400 V, 3W+N+PE or 3W+PE
AC voltage range0.8 – 1.2 Un
Nominal AC frequency50 / 60 Hz
Frequency range50 / 60 Hz, ±5
Power factor0.8 leading to 0.8 lagging
THDi<3 % at rated power
Maximum AC input power207 kVA
Maximum bypass current300 A
EPS peak AC output power155 kVA for 10 s
EPS LRA current300 A
EPS switching time<10 ms
EPS THDv<3 % at rated power
European efficiency98.1 %
Maximum efficiency98.5 %
DC input switchYes
Battery reverse polarityYes
PV reverse polarityYes
AC overcurrent protectionYes
AC/DC surge protectionClass II
ISO detectionYes
Residual current detectionYes
Ground fault detectionYes
AFCIYes
Terminal overtemperature protectionYes
String current detectionYes
Dimensions (W × H × D)730 × 1,060 × 305 mm
Operating temperature−30 °C to +60 °C
Cooling methodSmart air cooling
Operating altitude4,000 m
Humidity0 – 100 %
Noise<70 dB
Standby consumption<60 W
DC-link EV charger ready20 – 50 kW
Ingress protectionIP65
TopologyNon-isolated
DisplayLED, LCD, Wi-Fi + app
Communication portsUSB / RS485 / Bluetooth / Wi-Fi + LAN / 4G (optional) / CAN
Compliance and warranty
Grid connection standardsSee the certification documents attached to this listing
Warranty5 years standard, 10 years when the installation is registered with Fox ESS online
Specification sourceData Sheet Fox ESS H3 Plus EN, version 2.6, 26 August 2025
Goes with this

Ordered with this inverter more often than anything else

A hybrid is the middle of a system, not the whole of it. These are the parts our customers add most often:

Fox 3PH Meter (CHINT DTSU666)The three-phase CT meter this platform reads for self-consumption and export limitation.
Fox ESS AI Link - EMS Box for 3PH SystemAI Link EMS box for three-phase export limitation and multi-inverter control.
Fox ESS 4G-2 Dongle4G dongle for a site with no broadband at the inverter.
Frequently asked questions

Questions we get asked about this inverter

What does DC-link EV charger ready mean?

A DC fast charger can be connected directly to the inverter's DC bus, so energy goes from the battery to the vehicle without being converted to AC and back. It saves a conversion stage and the losses that go with it.

Why three battery ports?

Three stacks in parallel at 80 A each. At this scale battery power, not capacity, is usually the constraint — peak shaving is about kilowatts.

What is the bypass current for?

300 A of grid pass-through to the load, so the site keeps running at full current while the system charges or when it is not generating.

Is AFCI standard?

Yes on this range, along with string current detection and terminal overtemperature protection. On the smaller Fox hybrids those are options.

How heavy is it?

115 to 120 kg. Plan lifting and access.

ClearRay Solar

Documents, advice and trade pricing

Every datasheet, certificate, installation manual and warranty document we hold for this product is in the Documents tab below. See the rest of our hybrid inverter range, our batteries and our solar panels, or email sales@clearraysolar.com if you would like us to check a battery pairing or a string design before you order.

High Efficiency 98.5 %More power from the same roof space
IP65 RatedBuilt for UK weather conditions

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Documents & Certificates
Data Sheet Fox ESS H3 Plus EN Product Compatibility Fox Ess UK 2026 User Manual Fox ESS H3 Plus EN Warranty Fox ESS Inverter V2.3
Shipping & Returns

Delivery times vary by region:

  • UK — 1-2 business days
  • Highlands & Islands — 1-2 business days

Returns accepted within 14 days of delivery for unused items in original packaging.