The Fox ESS KH7 is a 7 kW single-phase hybrid solar inverter from Fox ESS's K-Series — engineered for larger domestic and light-commercial solar installations that demand serious performance. With three independent MPPT trackers, a maximum 15 kWp array capacity and a 600 V DC input ceiling, the KH7 is designed to extract maximum yield even from complex or shaded roof layouts. The inverter is fully compatible with Fox ESS's high-voltage lithium-ion battery range — including the ECS, HV2600, MIRA HV25 and EP series — enabling storage systems of up to 33.24 kWh by connecting up to seven batteries in series. An integrated EPS (Emergency Power Supply) function maintains power to critical loads during grid outages, switching in under 6 milliseconds with no reduction in output power. The fanless natural-cooling design keeps noise below 30 dB, the IP65 housing suits both indoor and outdoor wall installation, and the FoxCloud V2.0 monitoring platform provides real-time visibility via smartphone app or web portal. G99-certified for UK grid connection and MCS-compatible, the KH7 is a solid specification choice for any accredited solar and storage installer.
⚠️ Installer Requirement — MCS & Electrical Qualification
The Fox ESS KH7 must be installed by a competent, appropriately qualified electrical installer. For grid-connected solar PV systems in the UK, the installation must be carried out by an MCS-certified installer to ensure compliance with G99 grid-connection requirements and to qualify for the Smart Export Guarantee (SEG). All AC wiring must comply with BS 7671 (18th Edition IET Wiring Regulations). The KH7 carries G99 / EN50549 certification confirming it meets UK and European grid-connection standards. Where the inverter replaces an existing unit, the entire installation must be reassessed and re-notified as applicable.
⚡ Important: This Is a Hybrid Inverter, Not a Battery Retrofit Add-On
The KH7 is a combined solar inverter and battery storage controller. It accepts DC strings directly from solar panels via its three MPPT inputs and replaces any existing string inverter — it is not an AC-coupled retrofit device. For adding battery storage to an existing solar system without replacing the current inverter, consider the Fox ESS KA7 (AC-coupled version). The KH7 requires a CT clamp (supplied) to monitor grid import/export; a Modbus energy meter (optional accessory) is recommended when the distance from inverter to grid supply exceeds 30 metres. A second CT clamp is required if an additional generation source (e.g. wind turbine) is also connected.
☀️ SEG & FoxCloud: Monitoring & Export Made Simple
When installed by an MCS-certified installer, the KH7 qualifies for Smart Export Guarantee (SEG) payments on exported solar energy. The FoxCloud V2.0 monitoring portal provides comprehensive real-time and historical data — PV generation, battery state of charge, grid import/export and self-consumption — accessible via the Fox ESS smartphone app or browser. WiFi connectivity is included in the box; optional 4G and LAN dongles are available for sites without reliable WiFi. The KH7 also supports parallel operation of up to ten units for high-demand applications.
Key Features & Engineering Detail
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Three Independent MPPTs — More Power from Complex Arrays
Three separate MPPT trackers, each accepting up to 16 A input current and spanning 80–500 V, allow strings on different roof orientations or with independent shading profiles to be optimised independently. This avoids the yield losses that arise when mismatched strings share a single tracker — maximising annual generation from non-ideal roof configurations.
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High-Voltage Battery Architecture — Superior Round-Trip Efficiency
Operating at a recommended battery voltage of 300 V (range 85–480 V), the KH7's high-voltage design minimises resistive losses during charging and discharging. PV-to-battery charge efficiency reaches 98.5% and battery-to-AC discharge efficiency 97%, meaning very little stored energy is lost as heat — a meaningful advantage over lower-voltage systems over a battery's lifetime.
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FoxCloud V2.0 with Live EPS Monitoring
The FoxCloud V2.0 platform delivers real-time system monitoring including PV production, battery state of charge, grid power flows and load consumption. During EPS events, the cloud platform logs outage detail. The included WiFi dongle means connectivity is available from day one; 4G and LAN options cover challenging site environments.
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Sub-6 ms EPS Switchover — Uninterrupted Power for Critical Loads
The KH7's integrated Emergency Power Supply (EPS) detects grid loss and switches to battery supply in under 6 milliseconds — fast enough to prevent most sensitive electronics from resetting. EPS continuous output is the full 7 kVA with a 14 kW, 60-second peak to handle motor start-up surges. The inverter's output power is unchanged between normal and EPS modes.
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Fanless Natural Cooling — Quiet, Reliable, Low Maintenance
Unlike many comparable inverters, the KH7 uses natural convection cooling with no moving parts — resulting in below 30 dB typical noise (quieter than a library). Eliminating the fan removes the most common point of mechanical failure in inverters, improving long-term reliability and reducing the likelihood of performance degradation over the inverter's service life.
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Parallel-Ready Up to 10 Units — Future-Proof Scalability
The KH7 supports parallel operation of up to ten inverters, making it appropriate for large single-phase loads that would otherwise require a three-phase solution, or for phased system expansion as demand grows. Battery expansion is equally straightforward: up to seven battery modules can be connected in series, building a storage system up to 33.24 kWh without any additional hardware changes.
Technical Specifications — Fox ESS KH7
| PV Input |
| Max. Array Power |
15,000 Wp |
| Max. PV Input Power |
10,500 W |
| Max. DC Voltage |
600 V |
| Nominal DC Operating Voltage |
360 V |
| MPPT Voltage Range |
80 – 500 V |
| Start-up Voltage |
75 V |
| Number of MPPT Trackers |
3 |
| Strings per MPPT Tracker |
1 |
| Max. Input Current per Tracker |
16 A |
| Max. Short-Circuit Current per Tracker |
20 A |
| Max. Inverter Backfeed to Array |
0 mA |
| DC Disconnection Switch |
Optional |
| AC Output |
| Nominal AC Power |
7,000 VA |
| Max. Apparent AC Power |
7,700 VA |
| Rated Grid Voltage |
220 / 230 / 240 V (180–270 V range) |
| Rated Grid Frequency |
50 / 60 Hz (±5 Hz) |
| Nominal AC Current |
30.4 A |
| Max. AC Current |
33.5 A |
| Displacement Power Factor |
0.8 Lead – 0.8 Lag |
| THDi (at Rated Power) |
<3% |
| AC Input (from Grid) |
| Max. AC Input Power |
14,000 VA |
| Max. AC Input Current |
60.9 A |
| Rated Grid Voltage |
220 / 230 / 240 V (180–270 V range) |
| Rated Grid Frequency |
50 / 60 Hz (±5 Hz) |
| EPS Output (Emergency Power Supply — with Battery) |
| Max. EPS Continuous Power |
7,000 VA |
| EPS Peak Power (60 s) |
14,000 W |
| Max. EPS Current |
60.9 A |
| EPS Rated Voltage / Frequency |
220 / 230 / 240 V · 50 / 60 Hz |
| Grid-Loss Detection & Switch Time |
<6 ms |
| THDv (Linear Load) |
<2% |
| Parallel Operation |
Yes — up to 10 units |
| Battery |
| Battery Chemistry |
Li-Ion (high voltage) |
| Battery Voltage Range |
85 – 480 V |
| Recommended Battery Voltage |
300 V |
| Max. Charge Current |
50 A |
| Max. Discharge Current |
50 A |
| Battery Communication |
CAN / RS485 |
| Reverse Polarity Protection |
Yes |
| Max. Batteries in Series |
7 (up to 33.24 kWh) |
| Compatible Battery Range |
Fox ECS, HV2600, MIRA HV25, EP series |
| Efficiency |
| Max. Efficiency |
97.80% |
| European Efficiency |
97.40% |
| MPPT Efficiency |
99.90% |
| PV → Battery Charge Efficiency |
98.50% (full load) |
| Battery → AC Discharge Efficiency |
97.00% (full load) |
| Standby Consumption (idle) |
<2 W |
| Physical & Environmental |
| Dimensions (W × H × D) |
450 × 527 × 208 mm |
| Weight |
29 kg |
| Cooling Method |
Natural convection (fanless) |
| Topology |
Non-isolated, transformerless |
| Noise Emission (typical) |
<30 dB |
| Operating Temperature |
−25 to +60 °C (derating above +45 °C) |
| Storage Temperature |
−40 to +70 °C |
| Humidity |
0–95% RH (non-condensing) |
| Max. Installation Altitude |
<2,000 m |
| Ingress Protection |
IP65 |
| Protective Class |
Class I |
| Communications & Connectivity |
| WiFi |
Built-in (dongle included) |
| 4G / LAN |
Optional dongles |
| CT Clamp |
Included |
| Modbus Energy Meter |
Optional (recommended >30 m from grid supply) |
| Other Interfaces |
RS485, USB, DRM |
| Protection |
| PV Reverse Polarity |
Yes |
| Battery Reverse Polarity |
Yes |
| Anti-Islanding |
Active Frequency Drift with Positive Feedback |
| Output Short-Circuit |
Yes |
| Leakage Current Protection |
Yes |
| Insulation Resistance Detection |
Yes |
| Overcurrent / Overtemperature |
Yes |
| Overvoltage Category |
III (AC side) · II (DC side) |
| AC / DC Surge Protection |
Type II / Type II |
| AFCI Protection |
Optional |
| Certifications |
| Safety |
IEC 62109-1 / IEC 62109-2 / IEC 62477-1 |
| EMC |
EN 61000-6-1 / EN 61000-6-2 / EN 61000-6-3 |
| Grid Connection (UK) |
G99 / EN50549 / NRS 097-2-1 |
| Country of Manufacture |
China |
Frequently Asked Questions
Is the Fox ESS KH7 compatible with any battery brand?
No — the KH7 is designed to work exclusively with Fox ESS high-voltage lithium-ion batteries: the ECS series (ECS2900, ECS4100, ECS4300, ECS4800), the HV2600, MIRA HV25, and EP series. Up to seven battery modules can be connected in series, giving a maximum storage capacity of 33.24 kWh. Third-party batteries are not supported and their use would void the inverter warranty.
Does the KH7 provide backup power during a grid outage?
Yes. The KH7 includes a built-in EPS (Emergency Power Supply) function that automatically switches to battery power when grid loss is detected. The switchover occurs in under 6 milliseconds — fast enough to maintain most sensitive loads without interruption. EPS output is the full 7 kVA continuous, with a 14 kW, 60-second peak to handle motor and compressor start-up currents. No additional hardware is required to enable EPS.
Can I use the KH7 to retrofit battery storage to an existing solar system?
Not directly. The KH7 is a DC-coupled hybrid inverter — it accepts solar panels on its own MPPT inputs and replaces the existing inverter. It is not an AC-coupled device. If you wish to add battery storage without replacing a working inverter, the Fox ESS KA7 (AC Coupled Inverter) is the appropriate product from the same K-Series family, as it connects on the AC bus alongside an existing string inverter.
What monitoring is included, and do I need a separate data logger?
The KH7 comes with a WiFi dongle in the box, giving immediate access to the FoxCloud V2.0 platform — no separate data logger is needed. The app and web portal display live and historical PV production, battery state of charge, grid import/export and household consumption. Optional 4G and LAN dongles are available for sites without reliable WiFi. A CT clamp is supplied for grid monitoring; a Modbus energy meter is recommended when the cable run between the inverter and grid supply exceeds 30 metres.
Does the KH7 qualify for Smart Export Guarantee (SEG) payments?
Yes — provided the installation is carried out by an MCS-certified installer and the system is registered on the MCS database. The KH7 is G99-certified for UK grid connection and MCS-compatible. Once registered, the homeowner can apply to an SEG-licensed energy supplier to receive export payments for surplus electricity sent to the grid. Eligibility and payment rates vary by supplier.
Can multiple KH7 units be connected in parallel?
Yes. The KH7 supports parallel operation of up to ten units, making it possible to build a single-phase system with a combined output of up to 70 kW — suitable for large homes, farms, or light-commercial properties on a single-phase supply. Each unit must be individually configured and connected; refer to the Fox ESS installation manual for the correct parallel wiring and configuration procedure.
Specifications from Fox ESS K-Series Datasheet v2.3 (September 2025). Always verify against current manufacturer documentation before specifying. Installation must be carried out by a suitably qualified engineer in accordance with G99, BS 7671, and applicable MCS standards.
