Fox ESS is the UK’s number one residential battery storage brand, ranked first for domestic energy storage shipments across both the UK and Europe by S&P Global. If you’re considering a Fox battery for your home, you’re researching one of the most established and trusted names in the industry.
This guide covers the complete Fox ESS battery range – from the modular EP and EQ batteries to the all-in-one EVO and PowerQ systems – alongside the inverters, software integrations, and smart energy features that make Fox a compelling choice for homeowners. Whether you’re adding storage to an existing solar panel installation or planning a new solar-plus-battery system, residential battery storage currently qualifies for 0% VAT in Great Britain.
Infinity Energy Services installs the full Fox ESS range across southern England. If you’d like a personalised recommendation, we offer a free, no-obligation survey to help you find the right system for your home.
by David Lewis | first published 13 September 2024 | last updated 5 March 2026
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Who Are Fox ESS?
Fox ESS was founded in 2019 in Wenzhou, China, as a Sino-British partnership focused exclusively on residential and commercial energy storage. The company is backed by the Tsingshan Group, a Fortune Global 500 conglomerate that is the world’s leading nickel producer and among the top four lithium resource holders globally. This backing gives Fox ESS a significant advantage in terms of raw material supply chains, manufacturing capacity, and long-term financial stability.
The company has grown rapidly. Fox ESS now employs over 4,000 people and operates in more than 70 countries. In the first half of 2025, Fox ESS was ranked number one for residential energy storage shipments in Europe, the UK, and Poland, according to the S&P Global Energy Residential Energy Storage Index. The company also holds BNEF Tier 1 Energy Storage status – a distinction awarded by BloombergNEF to the most financially secure and technically reliable manufacturers.
Every Fox ESS battery uses lithium iron phosphate (LiFePO₄) cell chemistry. LiFePO₄ is widely regarded as the safest lithium-ion chemistry available – it is cobalt-free, thermally stable, and resistant to thermal runaway. Fox ESS reports zero combustion incidents across its global installed base, and maintains a UK-based technical support team to ensure rapid after-sales service for British customers.
Fox Battery Range at a Glance
Fox ESS offers four distinct product families, each designed for different household requirements. Understanding which category suits your home is the first step in choosing the right battery system.
FEATURE | H1/K + EP BATTERY | H1/K + EQ BATTERY | EVO ALL-IN-ONE | POWERQ ALL-IN-ONE |
Type | Modular (wall-mounted battery) | Modular (floor-mounted, stackable) | Yes – no kW limit | Consult LPA |
Capacity Range | 5.18 to 46.08 kWh | 9.32 to 41.94 kWh | 10.24 to 30+ kWh | 5.76 to 30.24 kWh |
Best For | Budget-conscious installations, flexible designs, future scalability | Reliable day-to-day storage, retrofits, limited wall space | Premium properties, aesthetic-conscious installations, high-demand homes | High-demand homes, fast installations, easy expansion |
Warranty | 10 years (battery) | 10-12 years (battery) | 12 years | 12 years |
Fox EP Battery Range
Key specifications:
- 5.18 kWh nominal capacity
- 4.66 kWh usable capacity
- 192V nominal voltage
- 27A max charge/discharge
- ≥4,000 cycle life
- ≥95% round-trip efficiency
- IP65
- 380 × 625 × 147 mm
- 50.5 kg
- Scalable to 20.72 kWh
Key specifications:
- 5.76 kWh nominal capacity
- 5.18 kWh usable capacity
- 192V nominal voltage
- 30A max charge/discharge
- LFP (LiFePO₄)
- Built-in fire suppression
- IP65
- 380 × 640 × 185 mm
- 51 kg
- Scalable to 23.04 kWh
Key specifications:
- 10.36 kWh nominal capacity
- 9.32 kWh usable capacity
- 384V nominal voltage
- 27A max charge/discharge
- ≥4,000 cycle life
- ≥95% round-trip efficiency
- IP65
- 710 × 625 × 147 mm
- 99 kg
- Scalable to 41.44 kWh
Key specifications:
- 11.52 kWh nominal capacity
- 10.37 kWh usable capacity
- 384V nominal voltage
- 30A max charge/discharge
- LFP (LiFePO₄)
- Built-in fire suppression
- IP65
- 710 × 640 × 185 mm
- 98 kg
- Scalable to 46.08 kWh
Can you mix and match batteries from the EP range?
We are often asked by customers who already have one or more Fox batteries installed if they can expand their storage. The answer is generally yes you can, but not all combinations of EP battery sizes are compatible with one another.
The following table illustrates what you can and can’t do, and what the implications are of specific combinations. Note that older versions of the EP5 and EP11 didn’t contain heating elements.
SCENARIO | SUPPORTED? | NOTES |
EP5 + EP6 Plus | YES | Fully compatible |
EP11 + EP12 Plus | YES | Fully compatible |
Heated + Heated | YES | Full warming functionality retained |
Heated + Non-Heated | YES | Warming disabled |
EP5/EP6 + EP11/EP12 | NO | Not permitted |
Fox EQ Battery Range
Key specifications:
- 11.52 kWh nominal capacity
- 10.37 kWh usable capacity
- 384V nominal voltage
- 30A max charge/discharge
- LFP (LiFePO₄)
- Built-in fire suppression
- IP65
- 710 × 640 × 185 mm
- 98 kg
- Scalable to 46.08 kWh
Fox EVO All-in-One
Key specifications:
- 10.24 kWh integrated battery
- 9.73 kWh usable capacity
- 5/8/10 kW inverter options
- 95% DoD
- IP66
- −20°C to 55°C
- Built-in fire suppression
- 200-300% PV oversize ratio
- 4 ms off-grid switching
- 12-year warranty
- 584 × 1,009 × 197 mm
- 113 kg
Fox PowerQ All-in-One
Fox ESS Inverters – The Heart of Every Modular System
If you choose a modular system with EP or EQ batteries, you will also need a Fox ESS hybrid inverter. The inverter converts the DC electricity generated by your solar panels and stored in your batteries into AC electricity that your home appliances can use. Although the inverter and battery are installed as separate units, they communicate constantly via high-speed proprietary data exchange to optimise charging, discharging, and energy flow in real time.
Fox ESS offers two single-phase hybrid inverter families for residential installations:
H1-G2 / AC1-G2 (3-6 kW)
The H1-G2 is Fox’s standard residential hybrid inverter, available in 3, 3.68, 5, and 6 kW versions. It features dual MPPTs (Maximum Power Point Trackers) and a 200% PV oversize ratio, meaning you can connect a solar array up to twice the inverter’s rated capacity. The AC1-G2 variant allows AC-coupled installation, meaning it can be fitted without solar panels – ideal for standalone battery-only systems charging from the grid.
Key specifications: 3-6 kW | Dual MPPT | 200% PV oversize | IP65 | Up to 97.08% max efficiency | EPS backup function | Fox Cloud V2.0 compatible
KH / KA Series (7-10.5 kW)
The KH/KA series is designed for larger residential solar arrays. Available in 7, 8, 9, 10, and 10.5 kW versions, these inverters feature three or four MPPTs for maximum design flexibility across complex roof configurations. The KH variant is the hybrid model (with solar inputs), whilst the KA is the AC-coupled version for battery-only installations.
With up to 10.5 kW of charge and discharge capability, the KH/KA series pairs particularly well with larger EP or EQ battery configurations and is the recommended choice for households with electric vehicles, heat pumps, or above-average electricity consumption.
Key specifications: 7-10.5 kW | 3-4 MPPTs | Up to 97.80% max efficiency | IP65 | EPS backup function | Fox Cloud V2.0 compatible
Fox Cloud 2.0 and Smart Energy Integrations
A battery is only as smart as the software controlling it. Fox Cloud 2.0 is the platform that connects your Fox ESS system to your smartphone (via iOS and Android apps) and a web portal, giving you real-time visibility over solar generation, battery state of charge, household consumption, and grid import and export.
Over 200,000 Fox ESS systems are now connected to Fox Cloud worldwide. The platform offers time-of-use scheduling (so you can set your battery to charge during off-peak tariff hours and discharge during expensive peak periods), AI-driven optimisation, performance analytics, and system health monitoring.
Smart Energy Platform Integrations
What truly sets Fox ESS apart from many competitors is its ecosystem of third-party software integrations. These platforms can significantly increase the financial return from your battery investment by automating energy trading, tariff optimisation, and grid services.
Capture AI provides smart optimisation – forecasting your solar generation, tracking energy tariff prices, and automatically charging or discharging your battery to minimise costs. It also enables participation in grid flexibility services, where you can earn additional revenue by helping to balance the national grid.
Axle Energy operates a Virtual Power Plant (VPP) that aggregates thousands of Fox ESS systems across the UK. By opting in, your battery can contribute stored energy back to the grid during peak demand events, earning you additional income on top of your normal energy savings.
Kraken (Octopus Energy’s technology platform) integrates directly with Fox ESS batteries. If you’re on an Octopus smart tariff such as Octopus Flux, Octopus Go, or Intelligent Octopus Go, Kraken’s automation intelligently controls your battery to maximise low-cost, low-carbon energy use – charging when electricity is cheapest and greenest, and discharging when prices are highest.
Enode is a secure energy connectivity platform that links Fox ESS systems with a wide range of clean-tech applications for seamless demand-response control. This opens the door to further energy supplier integrations as the smart energy market continues to develop.
Energy Supplier Partnerships
Fox ESS works in partnership with several of the UK’s leading energy suppliers, including Octopus Energy, OVO Energy, E.ON, and Hive. These partnerships mean that Fox battery owners can take full advantage of time-of-use tariffs and smart energy features that are increasingly central to reducing electricity bills.
Safety Features and Outdoor Installation
Safety is a legitimate concern for homeowners considering a battery in or around their home. Fox ESS addresses this with a multi-layered approach.
All Fox ESS batteries use LiFePO₄ (lithium iron phosphate) cell chemistry. Unlike the nickel manganese cobalt (NMC) chemistry used by some competitors, LiFePO₄ is cobalt-free and inherently more thermally stable. It has a significantly higher thermal runaway threshold, which means it is far less likely to overheat under fault conditions.
The newer Plus models (EP6 Plus, EP12 Plus) and the all-in-one systems (EVO, PowerQ) go further with built-in fire suppression systems. Combined with a multi-layer battery management system (BMS) that monitors cell voltage, temperature, and current in real time, these batteries provide several tiers of protection. Fox ESS reports zero combustion incidents across its entire global installed base.
For UK homeowners, outdoor installation is an increasingly attractive option. Under the PAS 63100 battery safety standard, batteries installed indoors should not be placed on escape routes. By installing your Fox battery outdoors, you avoid this constraint entirely. Every Fox ESS battery carries at least an IP65 weatherproofing rating (the EVO and PowerQ carry IP66), meaning they are fully protected against dust ingress and low-pressure water jets from any direction.
The smart battery warming feature – standard across the EP range and available on EQ systems – automatically activates an internal heater when temperatures drop below safe operating levels. This ensures reliable charging and discharging performance throughout the British winter, even on the coldest nights.
How to Choose the Right Fox Battery
Choosing the right battery depends on your household’s energy consumption, your solar panel array size, your budget, and your priorities around aesthetics and future expandability.
As a starting point, the average UK home consumes approximately 8-10 kWh of electricity per day. A battery in the 5-10 kWh range will typically cover overnight usage for a standard household with solar panels. If you have an electric vehicle that charges at home, a heat pump, or above-average electricity consumption, you may benefit from 10-20+ kWh of storage.
If your priority is value for money and future flexibility, a modular system – an H1-G2 or KH/KA inverter paired with EP or EQ batteries – offers the lowest cost per kWh of storage and the ability to add more batteries later as your needs evolve.
If aesthetics and simplicity are important, the EVO all-in-one delivers a premium look with minimal visible cabling and a single-unit installation. For high-demand homes that need substantial capacity from day one, the PowerQ all-in-one offers floor-standing modularity up to 30.24 kWh without the need for a separate inverter.
Infinity Energy Services provides a free, no-obligation survey to assess your home’s energy profile and recommend the optimal Fox ESS configuration. There is no one-size-fits-all answer – the right battery storage system depends on your specific circumstances, and that is exactly what our survey is designed to determine.
Fox Battery for Commercial Installations
Fox ESS also offers 3-phase solutions for commercial premises and larger residential properties with 3-phase electricity supplies. The Fox ESS H3 and H3-Pro 3-phase hybrid inverters are compatible with both EP and EQ battery ranges, available from 5 kW to 15 kW.
3-phase systems are typically required for commercial buildings, farms, offices, and larger homes with high electrical loads. They allow for balanced power distribution across all three phases and can support significantly larger solar arrays and battery configurations than single-phase systems.
Infinity Energy Services has extensive experience with both residential and commercial battery storage installations. If you are a business owner or manage a commercial property, contact us to discuss how a Fox ESS 3-phase system could reduce your energy costs and improve your energy resilience.
Fox Battery Warranty and After-Sales Support
Fox ESS provides robust warranty coverage across its product range. The EP battery range carries a standard 10-year product warranty with a minimum of 4,000 charge and discharge cycles. The EQ4800 carries a 10-year warranty with over 6,000 cycles. The EVO and PowerQ all-in-one systems both carry a 12-year warranty.
All warranties include a performance guarantee of 70% capacity retention at the end of the warranty period. This means that even after 10 or 12 years of daily use, your Fox battery is guaranteed to retain at least 70% of its original storage capacity.
Fox ESS maintains a dedicated UK-based technical support team, accessible by phone, email, and WhatsApp. The company also runs a Fox ESS Elite Installer programme, ensuring that accredited installers like Infinity Energy Services have received dedicated training on Fox products. On top of the manufacturer warranty, Infinity provides its own workmanship guarantee on every installation.
0% VAT and Financial Incentives
Residential battery storage installations in Great Britain currently qualify for 0% VAT. This applies to batteries installed alongside solar panels, batteries retrofitted to existing solar systems, and standalone battery installations that charge from the grid. The 0% VAT rate is in effect until 31 March 2027, after which it is scheduled to revert to 5%.
Beyond the VAT saving, Fox battery owners can benefit from additional financial incentives. The Smart Export Guarantee (SEG) allows you to sell surplus electricity back to the grid, with rates varying between energy suppliers. Time-of-use tariffs from suppliers like Octopus Energy enable you to charge your battery with cheap off-peak electricity and use that stored energy during expensive peak periods. And, through integrations like Axle Energy’s VPP, you can earn additional income by allowing your battery to participate in grid balancing services.
Infinity Energy Services also offers flexible finance options to help spread the cost of a Fox battery installation. Contact us for details.
Frequently Asked Questions
Are Fox ESS batteries any good?
Yes. Fox ESS is the UK’s leading domestic battery brand, ranked number one for residential energy storage shipments in the UK and Europe by S&P Global (H1 2025). All Fox batteries use LiFePO₄ chemistry for maximum safety and longevity, and the company holds BNEF Tier 1 Energy Storage status. Fox ESS reports zero combustion incidents across its global installed base.
How long do Fox ESS batteries last?
Fox ESS batteries are rated for a minimum of 4,000 cycles (EP range) or 6,000 cycles (EQ range). With one full charge and discharge cycle per day, this equates to approximately 10-16 years of operational life. The warranty guarantees at least 70% capacity retention at the end of the warranty period.
Can Fox batteries be installed outdoors?
Yes. All Fox ESS batteries carry a minimum IP65 weatherproofing rating (IP66 for the EVO and PowerQ). The EP and EQ ranges feature smart battery warming, which maintains safe operating temperatures during cold weather. Outdoor installation also simplifies compliance with the PAS 63100 battery safety standard by avoiding placement on indoor escape routes.
Do Fox ESS batteries work with Octopus Energy?
Yes. Fox ESS integrates with Octopus Energy via the Kraken platform. If you are on a smart tariff such as Octopus Flux, Octopus Go, or Intelligent Octopus Go, the system can automatically charge your battery when electricity is cheapest and discharge during peak-rate periods to maximise your savings.
What is the difference between Fox ESS EP and EQ batteries?
EP batteries are wall-mounted units that connect in parallel (side by side). EQ batteries are floor-mounted modules that stack in series (on top of each other). Both use LiFePO₄ chemistry and offer high scalability, but the EQ range has a longer cycle life (6,000+ versus 4,000) and is better suited to homes with limited wall space.
How much does a Fox ESS battery cost?
Costs vary depending on the battery model, capacity, inverter selection, and installation requirements. Residential installations currently benefit from 0% VAT in Great Britain. Contact Infinity Energy Services for a free, personalised quote based on your home’s specific needs.
Do Fox batteries provide backup power during a power cut?
Yes. Fox ESS systems equipped with EPS (Emergency Power Supply) functionality can provide backup power during grid outages. The EVO all-in-one offers particularly fast switchover times – as little as 4 milliseconds – and a 200% overload capability for 10 seconds to handle high-demand startup loads. If you require backup functionality, mention this at the start of your needs analysis so it can be included in the project.
Does Infinity Energy install Fox ESS batteries?
Yes. Infinity Energy Services is an experienced Fox ESS installer, serving Hampshire, Dorset, Wiltshire, Berkshire, Surrey, West Sussex, Oxfordshire, Gloucestershire, Somerset, and surrounding counties. We provide a complete turnkey service, from initial survey and system design through to installation, commissioning, and ongoing after-care.
The Right Fox Battery for Your Home
Fox ESS offers the most comprehensive range of residential battery storage available in the UK today. From the budget-friendly, scalable EP modular batteries to the premium, integrated EVO all-in-one, there is a Fox solution for virtually every home and every budget.
Every Fox battery uses safe LiFePO₄ chemistry, carries a robust manufacturer warranty, and integrates with leading smart energy platforms like Octopus Energy, Capture AI, and Axle Energy to maximise your financial return. Combined with 0% VAT on residential installations (until 31 March 2027) and the growing range of smart tariffs and grid services available to battery owners, there has never been a better time to invest in home energy storage.
Infinity Energy Services has been helping homeowners across southern England make the switch to clean energy since 2011. With thousands of completed installations, MCS accreditation, and dedicated after-sales support, we are the trusted choice for Fox ESS battery installation.
Contact us today for a free, no-obligation survey and personalised Fox battery recommendation. Call 0800 909 8882 or enquire below.