Best solar battery UK 2026: every battery we fit, ranked

We don’t fit every battery on the market, so this isn’t a lab test of everything you can buy. It’s the six batteries we chose to fit, ranked the way we’d walk you through them at the kitchen table, with what each does best and where each is weaker.

How we judged them

• Warranty, and its conditions. Not just the years. Most battery warranties guarantee a minimum share of the original capacity for a set time or a set amount of use, whichever comes first, and some depend on registering the system or keeping it connected to the maker’s app.
• Capacity range. How small you can start, and how far you can grow without replacing anything.
• Power-cut backup. Whole house or essential circuits only, built in or an extra box, and how quickly it switches over.
• Adding to existing solar. Whether it can sit alongside the inverter you already have, or replaces it.
• App and tariffs. Whether it can charge on cheap rates and run the house at peak times without you thinking about it.
• UK support. Who picks up the phone when something needs fixing.

The six batteries at a glance

Checked against each manufacturer’s UK product pages and datasheets (Hanchu through its UK distributor) in October 2026. Ranges change, so we confirm the exact model and warranty in your quote.

1. EcoFlow PowerOcean: best for built-in backup and a long warranty

The OCEAN 2 comes in 5 kWh and 8 kWh packs and goes up to 48 kWh on one inverter. Its 5 kWh packs carry 15 years as standard, the longest standard warranty of the six (the 8 kWh pack is 10 years with an optional 5). Backup is built in: in a power cut it keeps your essential appliances running, switching over in 0 ms as long as they draw no more than the inverter’s rated output (3, 5 or 6 kVA). The battery is IP66, so inside or out both work, and the app supports more than 500 dynamic tariffs.

Weaker on: powering the whole house in a cut, which on a single-phase supply needs EcoFlow’s separate gateway. EV charging isn’t built in, and for a house that already has panels it’s a hybrid, so the usual route is replacing your old inverter with EcoFlow’s.

2. Sigenergy SigenStor: best for EV owners

SigenStor is the one to beat if an electric car is part of your plans: a 12.5 or 25 kW DC charging module slots into the battery stack. Modules come in 6 and 9 kWh, up to six per stack (about 54 kWh), with inverters from 3 to 12 kW single phase and 5 to 30 kW three phase. Whole-home backup switches in 0 ms with the Sigen Energy Gateway, and the mySigen app plans charging around your tariff and the weather. It’s also flexible for existing solar: Sigenergy publishes an AC-coupled set-up that leaves your current inverter in place.

Weaker on: backup and EV charging are extras, and the standard warranty is 10 years (a paid extension takes it to 15). For a closer look, see Sigenergy vs EcoFlow.

3. Fox ESS: the most proven

Is Fox ESS any good? Yes. Fox says S&P Global data puts its UK market share above 35%, and it runs a UK national service centre, so support is local. We fit its EP6 (5.76 kWh) and EP12 (11.52 kWh) batteries, up to four per inverter, which takes the EP12 to 46 kWh. They’re IP65 with internal warming and a built-in fire suppressant. For existing solar, Fox makes a dedicated AC-coupled inverter, so your panels and inverter stay as they are. The FoxCloud app handles tariff scheduling.

Weaker on: backup and warranty small print. Fox’s hybrid inverter switches its backup circuits over in under 10 ms, but the whole house needs the EPS-BOX-SP gateway, which Fox says takes about 2 to 3 seconds, so the lights will blink. The battery warranty is 5 years, plus a free 5 when the system is registered and connected to FoxCloud, so it needs registering and keeping online.

4. Anker SOLIX X1: best for tight spaces and cold garages

The whole X1 system, battery and inverter together, is 15 cm deep, so it fits garage and utility walls that bulkier systems can’t. It’s rated to run from minus 20 °C to 55 °C, with built-in warming from 0 °C, and it’s IP66. It stacks 5 kWh packs up to 30 kWh on one system, with single-phase power from 3.68 to 6 kW. Whole-home backup comes with Anker’s Power Dock Pro, and Anker says its app connects with more than 830 energy providers for dynamic tariffs.

Weaker on: the warranty is 10 years, and whole-home backup needs the extra Power Dock Pro. It isn’t on Octopus’s compatible lists for Intelligent Octopus Flux or its Charge Pack. It’s a hybrid with its own solar inputs, so we check your existing inverter first.

5. Canadian Solar EP Cube: best for adding to existing solar

EP Cube puts the inverter and battery in one tower and supports both AC and DC coupling. Canadian Solar says it works with existing solar systems and other brands’ inverters, or takes new panels directly. That flexibility is why we reach for it when a house already has solar, or when an older battery needs replacing. On a single-phase supply it runs from 5 to 20 kWh in 5 kWh steps, with backup built in (up to 7.6 kW). The inverter has 10 years and the battery up to 15 years or 6,000 cycles, whichever comes first.

Weaker on: single phase tops out at 20 kWh, and there’s no EV charging in the stack. More on the EP Cube page.

6. Hanchu ESS: best value, the lowest-cost route in

Hanchu is our lowest-cost way into storage, and it’s still a good battery. The heated 5.12 kWh battery is IP66, the heated 9.4 kWh uses Blade LFP cells, and both carry a 12-year warranty, longer than Fox or Anker. Up to 16 batteries can run in parallel. Its UK distributor has a UK technical team and a national returns service with a 48-hour response, and the system can follow Octopus’s smart pricing automatically.

Weaker on: extras. Backup covers selected circuits rather than the whole house, there’s no EV charging, and for existing panels it’s a hybrid, so it usually replaces your inverter.

Which should you choose?

• You have an EV, or one is coming: Sigenergy.
• You want backup built in and the longest standard warranty: EcoFlow.
• You want the most widely used brand, with UK support: Fox ESS.
• The only space is a narrow or cold garage wall: Anker SOLIX X1.
• You already have panels and want to keep your inverter: EP Cube, Fox’s AC-coupled kit or Sigenergy. See adding a battery to existing solar.
• The budget is fixed: Hanchu.

Our verdict

If the budget stretches, start with EcoFlow or Sigenergy: they’re the two we’d put on our own walls. The other four each earn their place for a particular home, and none of them is a bad battery. We design your system remotely in OpenSolar, then our technical solar designer walks you through the options on a video call and the price is confirmed after a free remote survey. A battery added to existing panels is currently 0% VAT, until 31 March 2027.

Every battery side by side, with videos: which battery brand suits you.