Fox ESS KH9 9kW Single Phase Hybrid Inverter

Fox ESS KH9 9kW Inverter: The Ultimate Flexible Single-Phase Hybrid Solar Inverter

The Fox ESS KH9 delivers an impressive 9kW of single-phase hybrid inverter power, positioning it as a top-tier solution for UK homes with high energy consumption on a single-phase supply. Part of the sophisticated K-Series, it masterfully manages energy between extensive solar panel installations, compatible high-voltage batteries, and the grid, offering maximum self-sufficiency and powerful backup capabilities.

Ultimate Solar Harvest with Quad MPPT

What's the best solar inverter for intricate roof designs? The KH9 truly excels with its four independent Maximum Power Point Trackers (MPPTs), a standout feature confirmed in the K-Series technical information. This provides unparalleled design freedom for large solar panel systems spread across multiple roof sections, orientations, or experiencing complex shading. Each MPPT independently optimises its connected string (up to 16A max input current per string), guaranteeing the highest possible energy yield from your entire solar investment.

High-Power Battery Energy Storage Integration

This hybrid inverter is designed to work seamlessly with substantial battery energy storage systems. It supports compatible high-voltage LFP batteries (85-480V range) and manages them efficiently with a high maximum charge/discharge current of 50A, as specified in the product datasheet. This capacity allows for rapid charging from surplus solar and powerful discharging to meet peak household demands, significantly enhancing energy independence.

Maximise Savings & Efficiency

Invest intelligently in your energy future. The KH9 operates with very high efficiency (up to 97.80% Max. Efficiency listed in the specs), ensuring minimal energy loss. By enabling extensive use of stored solar energy, it dramatically reduces the need for costly grid electricity. Its smart functionality also allows for potential optimisation strategies using time-of-use tariffs, enabling programmed battery charging during off-peak hours.

Powerful & Reliable Backup Power (EPS)

Ensure continuity during power cuts. When connected to an appropriate battery bank, the KH9 provides a powerful 9kVA single-phase Emergency Power Supply (EPS) output. With a switchover time of less than 20ms cited in the technical data, it delivers near-instantaneous backup power to keep essential circuits running seamlessly when the grid fails.

Robust Design & Smart Connectivity

Built for performance, the KH9 features a durable IP65-rated enclosure suitable for outdoor installations (use correct cabling and mounting). Comprehensive remote monitoring of your entire energy system is available through the Fox ESS Cloud platform via optional WiFi, 4G, or LAN modules, providing valuable insights into performance and energy flow.

Why Evergy Recommend This Product

The Fox ESS KH9 stands out for demanding single-phase applications:

• High Single-Phase Output: 9kW capacity meets very high residential energy needs.
• Quad MPPT Flexibility: Offers ultimate optimisation for large, complex solar arrays.
• Efficient Battery Management: Supports significant storage capacity with high charge/discharge rates.
• Strong Backup Power: Delivers substantial 9kVA single-phase EPS (with batteries).
• Advanced Energy Control: Maximises self-consumption and supports smart tariff strategies.

Ideal For / Target Audience

This 9kW single-phase hybrid inverter is perfectly suited for:

• Large UK homes with very high electricity demand on a single-phase connection.
• Properties with extensive roof space accommodating large solar panel systems across multiple orientations.
• Homeowners installing significant battery storage capacity for near off-grid living or maximum savings.
• Users requiring powerful backup for a wide range of home circuits during power outages.

Technical Specifications Overview

Key specifications for the KH9 model, based on the datasheet, include:

• Nominal AC Output Power: 9000VA
• Max. Battery Charge/Discharge Current: 50A
• Number of MPP Trackers: 4
• Max. Efficiency: 97.80%
• EPS Output Power: 9000VA (Single Phase)
• Protection Degree: IP65

For comprehensive technical specifications, please review the specs tab or the Fox ESS K-Series datasheet. For slightly lower power requirements, consider the Fox ESS KH7 7kW version.

Achieve Peak Single-Phase Performance

Select the Fox ESS KH9 hybrid inverter for maximum flexibility and power in your large single-phase solar and storage installation. Ensure optimal performance by pairing with compatible high voltage batteries and high-output solar panels. Contact Evergy’s experts for bespoke system design and advice.

Seamless Integration with Solar Panels & Battery Storage

The Fox ESS KH9 integrates effortlessly with leading solar panels and Fox’s high-voltage LFP battery ecosystem. Using advanced DC coupling, it connects directly to battery modules (85–480 V) for efficient energy storage and export control. Installers can scale up to seven HV modules in series — enabling a total capacity of 33.24 kWh — providing flexibility for growing energy demands in larger households or small commercial applications.

By storing excess daytime generation for use in the evening, the KH9 helps reduce grid reliance and improves system payback. Its intelligent battery management supports both self-consumption and time-of-use optimisation, making it ideal for properties on smart export or agile tariffs.

Smart Monitoring & Connectivity

Every KH9 includes built-in FoxCloud connectivity, giving users real-time system data and installers full diagnostic access via smartphone or web portal. The platform supports live performance tracking, firmware updates and historical data analysis. Communication ports include Wi-Fi and LAN as standard, with optional 4G for remote or rural installations. Interfaces such as RS485, CAN, DRM, USB and CT inputs allow smooth integration with energy meters, battery systems, and smart control units.

With FoxCloud monitoring, homeowners can visualise generation, storage and consumption, empowering them to manage energy usage intelligently — while installers benefit from fewer site visits thanks to remote maintenance capability.

Compact Design & Rugged Construction

The KH9 combines high power density with installer-friendly design. It measures 450 × 527 × 208 mm and weighs approximately 29 kg, allowing single-person wall mounting. Its IP65-rated aluminium casing ensures long-term protection against dust and moisture, while passive cooling delivers quiet operation (<30 dB). The inverter’s ergonomic layout simplifies cable routing, making installation faster and cleaner in both residential and commercial settings.

Installer Guidance & System Notes

Why We Recommend the Fox ESS KH9

Evergy recommends the KH9 for projects requiring high performance, scalability and flexibility. Its quad MPPT architecture enables exceptional efficiency on complex roofs, while FoxCloud connectivity ensures transparent monitoring for both installers and end-users. Built for durability, it’s ideal for UK systems exposed to varied weather and evolving energy demands.

As the renewable division of LAMPS Electrical — an independent UK wholesaler with over 15 years’ experience — Evergy supplies genuine Fox ESS stock with UK warranty support, verified documentation, and professional technical advice. Our Oxfordshire-based renewables team is available to help design and specify systems for domestic or commercial sites.

Compare in the Fox K-Series Range

FAQs – Fox ESS KH9 9kW Single Phase Hybrid Inverter

For specification advice or compatibility checks, contact Evergy — your trusted UK supplier of solar batteries, inverters and renewable energy equipment.