Best solar batteries in the UK: how to choose the right one

There is no single best solar battery: the best one for you stores the energy your home can actually use, works with your inverter and supply, and comes with a UK warranty from a company that is still trading. A 13.5 kWh battery is wasted on a home that only has 5 kWh of evening use, and a battery whose maker has failed may leave you relying on your installer for repairs. Start with the situation you are in, then compare the specifications and warranty terms that change the decision.

The six batteries below are sold in the UK, with a UK support route and UK installers quoting them. This page isn't a ranking and gives no scores: each battery suits a different situation. Our editorial method explains how we choose which brands to cover and where the figures come from. If you are still deciding whether a battery is worth it at all, start with our solar battery storage guide.

Our shortlist by situation

Each brand has its own page with the detail: Tesla Powerwall, Sigenergy, Fox ESS, Enphase, SolarEdge and Sunsynk.

How we compared them

A battery gets onto this page only if it is present in the UK market: its maker's equipment is listed by MCS or on the Energy Networks Association's register, it has a UK distributor or support company, and UK installers quote it. These six aren't the only batteries that pass that test. We chose them because between them they cover the common situations in the shortlist, and because we have checked their datasheets and their UK or European warranty documents. We matched each one to a situation by how it is built: all-in-one or modular, AC-coupled beside existing panels or DC-coupled to a hybrid inverter, and which inverter it pairs with. Other batteries sold in the UK have their own pages too: BYD, Duracell Energy, GoodWe, Growatt, Huawei, myenergi, Pylontech, SolaX, sonnen and Sungrow.

For the six, we compared on the same basis for each:

• Usable energy per unit, not the rated or "nominal" capacity on the box.
• Power in kW: how much the battery can supply at once, which decides what runs together and whether your installer needs the network operator's approval.
• The efficiency figure the maker publishes, and what it actually measures.
• The warranty document for the UK or Europe, with its years, the capacity it guarantees, any limit on energy throughput, and its conditions.
• The company behind the warranty and its status on the day we checked.

We didn't test batteries ourselves, and figures come from each maker's own documents. Nobody pays to appear on this page or for a position in it.

The specifications side by side

From the datasheets and warranty documents we checked on 24 September 2026:

The Sunsynk usable figure is E.ON Next's listing for the battery it sells; the Fox figure is our arithmetic from Fox's datasheet (10.24 × 95% = 9.7). Sigenergy gives usable energy in its warranty.

Don't compare the efficiency column directly. Tesla's 89% covers the whole path from panel to battery to your appliances. Enphase's 90% is energy out against energy in at the AC side. SolarEdge's figure is a peak, and Fox gives the charging and discharging steps separately, not a round trip. None is wrong, but they measure different things. For savings sums, a round-trip figure of about 90% is a fair working assumption, and it is what our calculator uses.

Warranties: years, capacity and throughput

Warranty length is only part of it. Three other terms decide what you are covered for:

Retained capacity. Tesla guarantees 80% of 13.5 kWh after 10 years for Powerwalls installed in the UK; Enphase 70% at 10 years and 60% at 15; Fox 70% of nominal energy; Sigenergy 60% of usable energy. These are warranty thresholds, not forecasts of the capacity you will have.

Throughput limits. Several warranties end early once the battery has delivered a set amount of energy. Divide the limit by the usable capacity to see how many full charges that is:

• Sigenergy BAT 10.0: 30,660 kWh ÷ 8.76 kWh = 3,500 full charges, about 9.6 years at one a day;
• Fox ESS EVO 10: 47,880 kWh ÷ 10.24 kWh = 4,676 full charges, about 12.8 years at one a day;
• Enphase IQ Battery 5P: 6,000 cycles over 15 years, about 1.1 a day;
• Tesla Powerwall 3: unlimited cycles for solar self-consumption, time-of-use charging and backup, and 37.8 MWh for other uses.

This matters if you plan to charge from solar by day and again from a cheap overnight tariff: two cycles a day uses a throughput allowance twice as fast.

Staying online. Most of these warranties expect the system to stay connected. Tesla will honour at least 4 of its 10 years if the Powerwall is offline for long periods. Sigenergy cuts its warranty to 5 years after more than a year offline in total. Fox cuts the inverter warranty to 5 years if the system isn't connected to Fox Cloud within 120 days. Enphase requires a continuous internet connection. Keep the battery on your home broadband.

Your rights against the installer under the Consumer Rights Act 2015 are separate from the maker's warranty, and they matter most if a maker fails.

Backup in a power cut needs extra hardware

None of these batteries powers your home in a power cut unless the installation is designed for backup. A grid-connected system shuts down when the grid fails, and backup needs switching equipment, sometimes built into the unit but usually a separate box from the maker, wired to the circuits you choose:

• Tesla Powerwall 3: Backup Gateway 2, which Tesla's datasheet says is required for a backup installation. Without it, the Powerwall uses a Remote Meter and gives no backup.
• Sigenergy SigenStor: a Sigen Energy Gateway; Sigenergy says its HomePro SP-F model backs up a whole home on a 100 A single-phase supply.
• Fox ESS EVO: a built-in EPS (emergency power supply) output for chosen circuits, which the datasheet says switches in under 4 milliseconds, or Fox's EPS-BOX-SP whole-home gateway, which Fox says changes over in about 2 to 3 seconds.
• SolarEdge Home Battery 400V: a Home Hub inverter and the Home Backup Interface; the Home Wave inverter doesn't provide backup.
• Enphase IQ Battery 5P: Enphase lists the IQ System Controller in its UK storage warranty; ask your installer which backup equipment the design needs.

Ask which circuits will stay on, how much power they get, and to see the changeover tested at handover. Backup equipment is often priced separately, so check it is on the quote.

What size to choose

Size the battery to the energy your home uses between late afternoon and the next morning, and to your solar surplus. A larger battery adds little if you can't fill it. For a household using 2,500 kWh a year (Ofgem's typical figure), out for half the day, with 4 kWp of panels in Birmingham producing about 3,872 kWh a year, MCS's self-consumption tables show a battery storing:

Each figure is the rise in the share of solar used at home, from 19% without a battery to 52%, 59% and 60%, times 3,872 kWh. Doubling from 5 to 10 kWh stores about 21% more; going from 10 to 13.5 kWh adds 39 kWh a year. Homes with an electric car or heat pump, or on an overnight tariff, can use more storage; our solar battery storage guide works through both cases.

Published prices

Prices we read on 24 September 2026. They are starting prices from different sellers, so compare what each price covers before comparing totals:

Batteries installed in homes carry 0% VAT until 31 March 2027. Our solar battery cost guide gives prices by capacity, and Tesla Powerwall 3 price covers that battery in detail.

GivEnergy: why it isn't on the list

GivEnergy was a common UK battery brand, but GivEnergy Ltd has been in administration since 9 April 2026 and was still listed as "In Administration" on Companies House on 24 September 2026. Its administrator's office said in April, as reported by ESS News, that the company has ceased to trade and that GivEnergy Ltd will not honour further hardware warranties or user and software support.

We don't include GivEnergy batteries in this comparison. If you already own one, our GivEnergy page explains who to contact and in what order, starting with your installer.

Questions to ask about any battery

• What is the usable capacity, and how much is held back as a backup reserve?
• Which inverter will run it, and is that combination on the maker's compatibility list?
• Does the quote include backup hardware, and which circuits will it cover?
• Which document is the warranty, which company honours it in the UK, and what throughput limit does it set?
• Does the warranty need the battery to stay online, and what happens if it isn't?

Best solar batteries: FAQs

Which solar battery brand is best in the UK?

None is best for every home. Match the battery to your situation: a Tesla Powerwall 3 for high evening use and backup in one unit, a modular system such as Sigenergy SigenStor to start small, an AC-coupled Enphase IQ Battery 5P to add storage beside existing panels, and the matching battery if you already have SolarEdge or are buying a Sunsynk inverter. Then compare usable kWh, warranty terms and the full installed price.

How long will a 10 kWh battery last?

It depends on its usable capacity. A Fox ESS EVO 10 has about 9.7 kWh usable. Fox gives a best-case battery-to-home efficiency of 96.4%, so a full charge delivers a little over 9 kWh: enough to run a 500 W average load for about 18 hours (9 ÷ 0.5). Over its life, the warranty is the guide: 12 years or 47.88 MWh for the EVO 10.

How much does a 10 kWh solar battery cost in the UK?

Octopus Energy's battery-only price started at £5,336 for 10 kWh (read 24 September 2026). Our cost guide estimates about £5,100 installed on its own and about £4,200 when fitted with new panels.

Should I still buy a GivEnergy battery?

We don't recommend it. GivEnergy Ltd is in administration, and its administrator's office said, as reported by ESS News, that it will not honour further hardware warranties.