Fox ESS installer — Cube batteries and hybrid inverters

Quoted a Fox ESS system and want a second opinion, or want one fitted properly on Teesside or in North Yorkshire? We install Fox ESS battery and hybrid-inverter systems (including the Fox Cube battery) and have two complete installs documented on our YouTube channel.

Fox ESS is a battery and inverter manufacturer backed by the Tsingshan Group, with a UK arm at Loades Ecoparc in Coventry handling technical support, training and aftersales. When a battery faults six years in, you want that support desk in this country.

Fox does not sell direct: its quote page routes enquiries to a partner installer, and UK stock moves through a short list of distributors. Fox announced in May 2026 that S&P Global Energy's Residential Energy Storage Market Tracker ranked it number one in the UK for residential storage shipments by MWh in 2025 — Fox's own announcement of a third-party ranking, not an independent verification.

Fox's current UK residential line-up is three battery families — EQ, EP and CQ7 — plus three all-in-one units.

The EQ is a high-voltage floor-mounted stack you size in modules, at 90% depth of discharge and IP65. The warm-up function is not available on the EQ4800, and elsewhere works only when the stack has both master and slave units — if the battery is going in an unheated garage, which round here it often is, that decides the model.

The EP takes 10 years rather than 12 but wall-mounts, has internal warming and a fire suppressant, and needs a junction box when units are paralleled. The CQ7 is for genuinely large storage, but Fox states no warranty period for it and it is absent from the current UK and Ireland battery policy — so we will not quote a term until Fox confirms one.

The EQ4300 is missing on purpose: Fox's UK stack table and its own datasheet disagree on the per-module figure, and we will not print a number the manufacturer contradicts.

The battery stores; the inverter decides — sizing, backup and how much solar goes on the roof all come down to it.

H1-G2 and AC1-G2 — single-phase in 3, 3.7, 5 and 6 kW, dual MPPT, 200% PV oversize ratio, DC or AC coupled, IP65, pairing with the EP, EQ and CQ7. The H1-5.0-E-G2 takes 10,000 Wp of array for 5,000 W of output. The datasheet footnotes the 3.7 kW model as "3680 for G98" — the number deciding whether your job is a G98 notification or a G99 application.

KH and KA Series — single-phase 7, 8, 9 and 10 kW with three or four MPPTs, for larger arrays. It installs DC coupled, AC coupled or battery-ready — array this year, storage next.

Three-phase — the H3 Smart runs 5 to 15 kW with one battery input; the H3 Pro is 15 to 30 kW with two, up to 24 × CQ7 at 168.48 kWh. The H3 Plus, 50 to 125 kW, is commercial — see commercial solar.

Evo AIO is a wall-mounted box with the inverter and a 10.24 kWh battery in one unit, in 5, 8 and 10 kW options, IP66 and 95% depth of discharge, expanding through an EMS to three units for 30 kWh and above. Fox's UK page gives it a 12-year warranty, but Fox's UK inverter policy excludes the AIO series from its free extension — we would want the inverter side confirmed before you rely on 12 years.

PowerQ AIO is floor-mounted and stackable, in five UK inverter options (3.7, 5, 8, 10 and 12 kW) pairing to the EQ5000 from two to six modules, 9.84 to 29.52 kWh, with an EPS backup gateway, IP66 and a 12-year warranty.

MiniQube is plug-in storage from 2.11 kWh to 10.55 kWh in 2.11 kWh modules, which Fox describes as self-install without a meter. It is not what we do: for a plug-in unit in a flat you do not need an MCS installer and scaffolding.

A Fox battery alone will not keep your lights on in a power cut; the EPS-BOX-SP single-phase backup gateway is the part that does. On grid loss it isolates the property and restores power from battery and solar, with a typical changeover of around two to three seconds. It is rated 100 A maximum utility input and 100 A output, is IP65, and works with the H1-G2, AC1-G2, KH/KA Series, Evo and PowerQ.

Two to three seconds is not an uninterruptible supply — lights and the fridge will not care, a desktop PC without a UPS will reboot. Fox also qualifies full-home backup as subject to system sizing, so we agree the backup circuits at survey.

Two complete Fox jobs are documented on our YouTube channel and on this site:

• A 9.6 kW solar array with a Fox Cube battery in Ingleby Barwick — a full solar-and-storage retrofit on an occupied home.
• A Fox Cube battery with JA Solar panels on a garage roof — for when the house roof is the wrong pitch or overshadowed.

An honest note on the word "Cube". Fox's own name for its ECS modular battery family is "Energy Cube", and ECS is what is in those videos — the previous generation, absent from Fox's current UK residential range and from the current UK and Ireland battery warranty policy, so new installs from us use the EQ range. If you already own a Cube, the warranty that applies is the one in force when it was installed. More of our work is on the projects and reviews pages.

It suits you if you are buying on value rather than badge. In our experience it is where people land when they want the most usable storage for the budget.

It suits you if you are having solar fitted at the same time — one hybrid inverter doing both jobs is tidier and cheaper than AC-coupling a battery onto a separate solar inverter — or if you want to start small and grow, because the EQ and CQ7 stacks add modules and the K Series can go in battery-ready.

It does not suit you if you want one manufacturer's name across the whole system in the simplest possible box: that is the Powerwall 3 argument, and we will make it for you when it is the better buy — we are a Tesla Certified Installer, one of around 50 in the UK. Nor if you are hoping to extend an old ECS Cube stack.

Tesla Powerwall 3 is the tidiest single-box answer with the strongest brand recognition of the three. Sigenergy's SigenStor is the most flexible if you want solar, storage and EV DC charging in one tower. Fox ESS wins on breadth: more battery families, more inverter sizes, more ways to grow later.

The long versions: Fox ESS vs Tesla Powerwall 3 and Sigenergy vs Fox ESS. Still working out size and type? Start with the battery storage buying guide. The other hubs are Tesla Powerwall installer and Sigenergy installer.

FoxCloud is Fox's monitoring platform, in a browser and in the app: real-time performance, history by day, week, month or year, battery health, and control of the charge/discharge schedule. There is a Manual Tariff mode with up to 96 slots and a one-click Smart Tariff option, with Octopus, OVO, Kraken, E.ON and Hive shown as partners. FoxCloud 2.0, announced in February 2026, adds a five-second refresh and an AI Mode, though Fox notes some features were not in the initial release.

Capture AI is the part worth understanding: it predicts your consumption and generation, charging when electricity is cheapest and discharging at peak. Fox says it works with all suppliers and tariffs in the UK, is included free of charge with all Fox ESS systems, and that optimisation savings are 100% yours, with Capture retaining a share only of grid-services earnings. That is unusual and a genuine reason to look at Fox, if you are on a tariff worth optimising against. If not, read the tariff side first.

Fox's UK and Ireland battery warranty policy, version 4.5 of September 2025, gives the EQ range, EVO5 and EVO10 144 months from installation — 12 years — but no more than 149 months from the date of manufacture. That manufacture cap is why we ask how long a battery has sat in a warehouse.

The performance side warrants at least 70% of nominal energy for that term or until a minimum energy throughput, whichever comes first: 12.15 MWh on the EQ2900, 18.45 MWh on the EQ5000, 21.6 MWh on the EP6. Cycle hard on a cheap-rate tariff and throughput, not years, ends the warranty. Fox also requires operating temperature between -10°C and 50°C and 300 mm of clearance around the pack.

Inverters are separate: 60 months from installation as standard, plus 60 months free — 10 years total — for the listed series including the hybrids, provided the warranty is registered on Fox's website before 36 months from the date of manufacture and the device is registered to Fox Cloud using a Fox datalogger. So the datalogger and the registration are not optional: skip them and you give away five years of cover. We register what we fit — inverter and battery warranties go in separately — and pass you the certificates. Under Fox's policy only the installer and Fox's own personnel can claim, so choose a firm you expect to still be trading in ten years.

The call. Tell us the house, the roof, and what you are trying to fix — high bills, a coming EV, power cuts, or all three.

The survey. Andy Pemberton surveys and specifies every system we fit: where the stack can live with 300 mm of clearance and a sane ambient temperature, whether the consumer unit and earthing need work, and which inverter the array size points to.

The paperwork. Northern Powergrid is the network operator here, so it is a G98 notification or a G99 application depending on inverter size. We handle it.

The quote. Fixed, in writing, against a named list of kit: battery and inverter models, module count, whether the backup gateway is included, and what the electrical works cover.

Install and commissioning. Our own team. We set the tariff mode in FoxCloud, register the MCS paperwork and the Fox warranties, and walk you through the app before we leave. Our solar maintenance page covers other firms' systems.

Nobody publishes a UK price for Fox ESS, Fox included — its own site routes quote requests to installers. We will not put a number here that we would have to walk back on your driveway. Ask us and you get a fixed price in writing against a specified list of kit.

What moves it: which battery family and how many modules; whether the inverter is doing the solar too, since a hybrid usually beats AC-coupling onto a separate inverter on a new install; whether you want the backup gateway; scaffolding; and what the consumer unit and earthing arrangement need first. On tax, HMRC's Notice 708/6 zero-rates the installation of specified energy-saving materials until 31 March 2027, reverting to the 5% reduced rate from 1 April 2027, and since 1 February 2024 that has included storage batteries in residential property.

We work from Kirklevington, just outside Yarm, and Fox systems go in across Teesside, County Durham and North Yorkshire — the TS, DL, DH, YO and HG postcode areas. Both of our filmed Fox installs are Teesside jobs.

For your town: Middlesbrough, Stockton, Darlington, Yarm and Hartlepool — or the battery storage and solar panel installation hubs.