10 kW AC Output4 MPPT Inputs21 kWp Max PV97.8% Max Efficiency97.4% Euro EfficiencyIP65 Indoor / OutdoorEPS <10ms BackupG99 CertifiedNatural Cooling — SilentWi-Fi Dongle & CT Included10-Year Warranty (registered)Parallel Up to 10 Units
The Fox ESS KH10 (FE-KH1-10.0) is the 10 kW model in the Fox ESS K Series single-phase hybrid inverter range — designed for UK homes with large or complex solar PV systems that exceed the capacity of standard 3.6–6 kW inverters. With four independent MPPT inputs supporting up to 21 kWp of PV, it handles multi-orientation roof layouts that would cause losses in dual-MPPT inverters. High-voltage battery compatibility (85–480V), a peak efficiency of 97.8%, EPS backup in under 10ms and completely silent natural cooling make the KH10 one of the most capable single-phase hybrid inverters on the UK market at this power level. IP65 rated for outdoor installation, it ships with Wi-Fi dongle and CT clamp and carries full G99 UK grid certification. A 10-year warranty is available on registration within 30 days of commissioning.
10 kW
AC Output
4
MPPT Trackers
21 kWp
Max PV Input
97.8%
Max Efficiency
18 kVA
Max EPS Backup
10 yr
Warranty
⚠ G99 Application Required: At 10 kW, this inverter is above the 3.68 kW G98 threshold. A formal G99 application must be submitted to your DNO before commissioning. Your MCS-registered installer will manage this process — allow 4–8 weeks for approval. Also note: a 10-year warranty requires online registration within 30 days of install; without registration the warranty defaults to 5 years.
✅ 10-Year Warranty: Register your installation at the Fox ESS portal within 30 days of commissioning to activate the full 10-year product warranty. Without registration, the standard warranty is 5 years. Your installer can complete registration on your behalf.
Fox ESS KH Series Range — at a Glance
Model
AC Output
Max AC
MPPTs
Max PV
Max I BAT
Max EPS
KH7
7,000W
7,700VA
3
15,000Wp
30A
14,000VA
KH8
8,000W
8,800VA
3
16,000Wp
32A
16,000VA
KH9
9,000W
9,900VA
4
18,000Wp
36A
18,000VA
KH9.9
9,900W
9,900VA
4
20,000Wp
40A
18,000VA
KH10 ✓
10,000W
10,500VA
4
21,000Wp
43A
18,000VA
KH10.5
10,500W
10,500VA
4
21,000Wp
45A
18,000VA
All models: IP65, G99 certified, natural cooling, CAN/RS485 comms, 97.8% max efficiency. This listing covers the KH10 (10 kW) row.
Key Features & Technology
10 kW Rated AC Output — Sized for Large Single-Phase Arrays
At 10 kW rated output, the KH10 is designed for UK homes with substantial solar PV systems — typically 8–21 kWp arrays that would exceed the capacity of standard 3.6–6 kW hybrid inverters. The maximum apparent AC power of 10,500 VA and maximum AC current of 43.5A ensure full output can be sustained under peak demand.
4 Independent MPPT Inputs — Up to 21 kWp of Solar
Four independent Maximum Power Point Trackers (MPPTs) are the defining feature of the KH series — more than any other Fox ESS single-phase inverter. Each MPPT accepts one string with up to 16A input current and 500V DC maximum, supporting a combined maximum array of 21,000 Wp (21 kWp). Four independent MPPTs mean panels on different roof aspects, pitches or orientations can each be tracked at their individual optimum — maximising generation from complex roof layouts.
99.9% MPPT Efficiency — Starts at 75V
MPPT efficiency of 99.9% ensures virtually all available power from each string is captured and converted. The MPPT voltage range of 80–500V with a start-up voltage of just 75V means the inverter begins harvesting solar energy at very low irradiance — earlier in the morning, later in the evening, and during overcast conditions.
97.8% Peak Efficiency / 97.4% European Weighted
With a maximum efficiency of 97.8% and European weighted efficiency of 97.4%, the KH10 converts PV generation to usable AC power with minimal losses. Battery charge efficiency (PV to battery) is 98.5% and discharge efficiency (battery to AC) is 97.0% — keeping round-trip losses to a minimum across the full system.
EPS Emergency Power Supply — <10ms Transfer, 18 kVA Backup
The built-in Emergency Power Supply (EPS) output switches from grid-tied to backup mode in under 10ms — fast enough that most home appliances and computers continue operating without interruption. The EPS output delivers 230V / 50Hz at up to 18,000 VA peak from battery storage, with less than 2% THDv on linear loads. The home operates normally from battery during outages, with no change to inverter output power.
High-Voltage Battery Compatible — ECS and EP Series
The KH10 is compatible with the full range of Fox ESS high-voltage batteries — ECS2900, ECS4100, ECS4800, HV2600 and the EP series — with a battery voltage range of 85–480V and maximum charge/discharge current of 50A/50A. Up to seven ECS battery modules can be installed in series, giving a maximum storage capacity of 33.24 kWh (or up to 33.6 kWh in some configurations) from a single inverter.
IP65 — Outdoor Installation Without Additional Enclosure
IP65 ingress protection means the KH10 is fully protected against dust and water jets, making it suitable for permanent outdoor wall mounting without a weatherproof enclosure — saving space inside the property. Operating temperature range is -25°C to +60°C (with derating above 45°C), covering all UK outdoor conditions across every season.
Natural Cooling — Completely Silent Operation
The KH10 uses passive natural convection cooling with no fans, making it completely silent in operation — noise emission is typically less than 30 dB. Fanless design also eliminates the most common inverter maintenance issue (fan failure) and removes any ingress risk from a fan aperture, contributing to the IP65 rating.
Parallel Operation — Up to 10 Units
Up to 10 KH10 inverters can be operated in parallel, scaling the system to 100 kW of AC output for larger properties, commercial rooftop installations and energy-intensive applications. This makes the KH series a future-proof choice for installations that may grow over time.
Supplied With: Wi-Fi Dongle and CT Clamp
The KH10 ships with a Wi-Fi dongle for connection to the Fox Cloud / FoxESS monitoring app (LAN and 4G dongles available optionally) and a CT clamp for zero-export control and grid monitoring. A Modbus meter is optional if the distance from inverter to grid supply exceeds 30m or for installations with another generation source (wind, hydro). Type II AC and DC surge protection is built in.
10-Year Warranty — Register Online Within 30 Days
Fox ESS provides a 10-year product warranty when the installation is registered online within 30 days of commissioning. If registration is not completed, the standard warranty period is 5 years. Warranty registration is straightforward via the Fox ESS portal. The inverter carries G99 certification (EN50549) for UK grid connection, plus IEC62109-1/2 safety.
FoxCloud V2.0 — Advanced Remote Monitoring
The KH10 integrates with FoxCloud V2.0, providing real-time and historical monitoring of generation, consumption, battery state, grid import/export and system status via the Fox ESS smartphone app or web portal. Communication interfaces include Wi-Fi, LAN, 4G (optional), USB, CT, RS485 and DRM.
Supplied With
✓ Wi-Fi dongle (FoxCloud monitoring)
✓ CT clamp (zero-export / grid monitoring)
✓ Wall mounting bracket
✓ Built-in Type II AC & DC surge protection
✓ Built-in DC disconnection switch
✓ Quick installation guide
Optional: LAN dongle, 4G dongle, Modbus meter (required if inverter-to-grid distance >30m or second generation source present).
Technical Specifications — Fox ESS KH10 / FE-KH1-10.0 (Datasheet V2.0)
PV Input (KH Hybrid Mode)
Max. Array Power
21,000 Wp (21 kWp)
Max. Input Power
15,000 W
Max. DC Voltage
600 V
Nominal DC Operating Voltage
360 V
Max. Input Current (per MPPT)
16A per input (4 inputs)
Max. Short Circuit Current (per MPPT)
20A per input
MPPT Voltage Range
80 – 500 V
Start-up Voltage
75 V
Number of MPPT Trackers
4
Strings per MPPT
1
DC Disconnection Switch
Yes
Max. Inverter Backfeed to Array
0 mA
AC Grid Output
Rated AC Output Power
10,000 W
Max. Apparent AC Power
10,500 VA
Max. AC Output Current
43.5 A
Rated Grid Voltage (AC Voltage Range)
220 / 230 / 240 V (180–270 V)
Rated Grid Frequency
50 / 60 Hz ± 5%
Displacement Power Factor
0.8 Leading to 0.8 Lagging
THDi (Rated Power)
< 3%
EPS / Backup Output (with Battery)
Max. EPS Power
18,000 VA
Max. EPS Current
78.3 A
EPS Rated Voltage / Frequency
220 / 230 / 240 V, 50 / 60 Hz
Switch Time
< 10ms
THDv (Linear Load)
< 2%
Parallel EPS Operation
Yes (max 10 units)
Battery Interface
Compatible Battery Type
Li-Ion (Fox ESS HV / ECS series)
Battery Voltage Range
85 – 480 V
Recommended Battery Voltage
300 V
Max. Charge Current
50 A
Max. Discharge Current
50 A
Communication
CAN / RS485
Reverse Connect Protection
Yes
Max. Battery Capacity (ECS series)
33.24 kWh (7 modules in series)
Efficiency
Max. Efficiency
97.8%
European Weighted Efficiency
97.4%
MPPT Efficiency
99.9%
Max. Battery Charge Efficiency (PV to BAT)
98.5%
Max. Battery Discharge Efficiency (BAT to AC)
97.0%
General
Dimensions (W × H × D)
450 × 527 × 208 mm
Weight
29 kg (KH)
Ingress Protection
IP65
Protective Class
Class I
Operating Temperature
-25°C to +60°C (derating above 45°C)
Humidity
0% – 95% (no condensation)
Max. Altitude
< 2,000 m
Storage Temperature
-40°C to +70°C
Cooling
Natural convection (fanless)
Noise Emission
< 30 dB (typical)
Topology
Non-isolated (transformerless)
Standby Consumption
< 15 W
Communication
Interfaces
Meter (optional), Wi-Fi, 4G (optional), DRM, USB, CT, RS485
Monitoring
FoxCloud V2.0 — app & web portal
Certifications & Standards
Safety
IEC 62109-1 / IEC 62109-2 / IEC 62477-1
EMC
EN 61000-6-1 / -6-2 / -6-3
Grid Connection
G99 / EN50549 / NRS 097-2-1
AC/DC Surge Protection
Type II / Type II
AFCI Protection
Optional
Warranty
Standard Warranty
5 years
Extended Warranty (with registration)
10 years — register within 30 days of commissioning
Part Number
FE-KH1-10.0
ℹ Installation Note: The FE-KH1-10.0 must be installed by a qualified electrician or MCS-registered installer in accordance with BS 7671, G99 grid connection requirements and the Fox ESS installation manual. A Modbus meter is required if the distance from the inverter to the grid supply exceeds 30m, or if a second generation source (wind, hydro etc.) is present. A second CT clamp will be required if a second generation source is in use.
Frequently Asked Questions
Why choose the KH10 over the Fox H1 10kW inverter?
The key difference is the number of MPPT inputs. The KH10 has 4 MPPTs versus the H1's 2 MPPTs, and supports a much larger maximum array of 21 kWp vs 12 kWp. This makes the KH series the right choice for larger or more complex roof installations — particularly where panels face multiple orientations, or where the site has a large roof area that warrants a higher-capacity array. For simpler 2-string systems, the H1 is sufficient.
Does the KH10 require a G99 application?
Yes. The KH10 outputs 10 kW of AC power, which is above the 3.68 kW G98 threshold. A formal G99 application to your Distribution Network Operator (DNO) is required before commissioning. The inverter holds G99 certification (EN50549) and your MCS-registered installer will handle the application. Allow 4–8 weeks for DNO approval, though timescales vary by network operator.
What batteries are compatible with the KH10?
The KH10 is compatible with the full range of Fox ESS high-voltage batteries: ECS2900, ECS4100, ECS4800, HV2600 and the EP series (EP6, EP12). Battery voltage range is 85–480V. Up to seven ECS modules can be stacked in series for a maximum capacity of 33.24 kWh. The inverter communicates with the battery BMS via CAN/RS485 for intelligent charge management.
How does the EPS backup work during a power cut?
The KH10 has a dedicated EPS (Emergency Power Supply) output circuit. When grid power fails, the inverter switches to EPS mode in under 10ms — imperceptibly fast for most appliances. Connected loads continue to run from battery storage at 230V / 50Hz with up to 18,000 VA available from the EPS output. The EPS continues until the battery is depleted or grid power is restored. Note: EPS operation requires a compatible battery to be installed.
What is the warranty if I don't register online?
Without online registration, the standard warranty is 5 years. By registering the installation on the Fox ESS portal within 30 days of commissioning, the warranty extends to 10 years. Registration is straightforward — your installer can complete this on your behalf. Always confirm registration has been completed to protect your investment.
Related Products
Fox ESS EP12 Plus 11.52kWh Battery
High-voltage LFP battery — compatible with KH10
Fox ESS EP6 Plus 5.76kWh Battery
Half-capacity HV battery option for KH10
Fox ESS KH10.5 Hybrid Inverter
10.5kW variant — highest output in KH range
TypeHybrid Inverter
VendorFox ESS
SKUFE-KH1-10.0
BTU & WATT Calculator
Room Dimensions
Room Type
Living Room
Bedroom
Kitchen
Bathroom
Conservatory
Hallway
Glazing Type
Single Glazed
Double Glazed
Triple Glazed
External Walls
0 Wall
1 Wall
2 Walls
3 Walls
4 Walls
Insulation Level
Poor
Average
Good (New Build)
Required Heating
0
Watts
0
BTUs
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