Fox ESS MiniQube UK: capacity, plug-in claims and G98 checks

What the Fox ESS MiniQube is

The Fox ESS MiniQube is a compact energy storage product that Fox ESS presents in hybrid, AC and portable configurations. The maker's UK page positions it for smaller homes, apartments and retrofits, with modular storage rather than a single fixed battery size.[1]

That description is not the same as a UK permission to connect it in any way you like. The page combines a standard-socket plug-in claim with a warning that formalised plug-in battery guidance remains limited. Read the connection qualification as carefully as the headline.[1]

Capacity and configurations

Fox ESS lists 2.11 kWh modules and a stackable range up to 10.55 kWh. That is an advertised range, not a guarantee that every version has the same usable energy, inverter behaviour or connection options. Ask for the exact model, module count and usable capacity on the quotation or final instructions.[1]

The maker also lists hybrid and AC versions, a battery-only option and direct PV input on the hybrid configuration. Its integrated portable socket is described as delivering up to 1.2 kW. Treat that as an own-socket output figure, not as the MiniQube's house-feed or export rating.[1]

There is no price on the maker page checked for this guide on 7 September 2026. Do not fill that gap with a price for a different MiniQube configuration or with a retailer listing that does not identify the exact model.

Portable socket use is not house-wiring feed-in

There are two different questions hidden inside the words plug-in battery:

• Own-socket use: an appliance or extension lead plugs into the MiniQube's integrated socket. The unit is acting as portable, off-grid power. Energy is not being sent into the house consumer unit.
• House-wiring use: the battery is arranged to exchange energy with the home's circuits, solar system or grid. That is an electrical installation and network connection question, even if the product enclosure has a plug.

The first use is closer to a portable power station. It can be useful for a device, shed or temporary backup, but it does not by itself shift the whole home onto cheap-rate electricity. The portable power station comparison explains the boundary, while the MiniQube product page records the maker's current configuration claims.[1][8]

If you want it connected to house wiring

Fox ESS's UK clarification says that, until plug-in battery frameworks are fully defined, MiniQube installations should follow existing UK electrical and grid compliance standards. It specifically refers to a dedicated circuit and ENA Engineering Recommendation G98 where applicable.[1]

If you want the MiniQube to support your house wiring, ask the installer to state the connection arrangement, the maximum AC import and export, the exact variant, and which DNO process applies. The answer can depend on the inverter, other generation at the property and the network area. A product page saying plug-in does not remove those checks.[1][5]

The IET's domestic energy storage guide covers electrical design, fire and electrical safety, inspection, testing and commissioning. Energy Saving Trust likewise recommends using an experienced professional for a home battery installation. Those sources do not turn a marketing claim into approval, but they explain why the site and installation need checking.[6][7]

G98 is about the connection, not kWh

The current ENA catalogue lists G98 A1 Issue 2 as the recommendation for fully type-tested micro-generators up to and including 16 A per phase. SSEN describes the familiar single-phase equivalent as 3.68 kW or less per phase at one property, with a G98 Form B notification within 28 days of commissioning for an applicable installation.[4][5]

Those figures describe electrical connection capacity, not stored energy. A 10.55 kWh stack is not automatically a G99 system, and a 2.11 kWh unit is not automatically G98. The inverter, export capability, total generation, number of units, site conditions and type-test evidence all matter. If the arrangement is outside the G98 route, ask the DNO or installer whether G99 or another application is required.[4][5]

The 2026 government route does not close this gap. The plug-in solar interim specification applies specifically to plug-in solar products and does not extend to plug-in batteries.[2] The government announcement about solar becoming legal from 27 August 2026 is therefore not a blanket approval for a MiniQube feeding a UK socket or house circuit.[3] Read the G98 home battery guide for the notification, approval and paperwork questions.

What to verify before buying

Before paying for a MiniQube, get clear answers to these product-specific questions:

1. Which mode are you buying? Own-socket portable power, hybrid solar storage, AC storage or a connection to house wiring are not interchangeable uses.
2. What is the exact configuration? Confirm module count, usable capacity, inverter or socket output, PV inputs and the functions included in that version.
3. What happens at your property? Ask whether a dedicated circuit, electrician, DNO notification, prior approval or other paperwork is needed. Get the proposed route in writing.
4. What documents support the claim? Ask for current installation instructions, relevant type-test evidence, a schematic and commissioning or notification documents where applicable.
5. What is actually available? The maker page had no published price when checked on 7 September 2026. Check price, stock, warranty and after-sales support for the exact UK configuration rather than assuming they are settled.

If the answer to the connection question is vague, pause the purchase. Use the home battery calculator only after you know that the proposed system can legally and safely perform the job you are modelling. For wider alternatives, compare the MiniQube with the products in our UK plug-in home battery shortlist, which keeps portable, wired and emerging products separate.

Our verdict

MiniQube is interesting because it combines stackable storage with a portable own-socket mode. That could suit a buyer who wants movable appliance power, or someone assessing a compact solar or tariff-storage system, but those are different electrical jobs.[1]

The safe buying position is simple: do not treat plug-in wording as proof of a permitted house-wiring connection. Confirm the exact configuration, installation method, current UK instructions, DNO route, price and paperwork first. Then use the UK plug-in battery rules guide and the no-solar battery guide to test the wider decision.