Solar Batteries Explained: Are They Worth It in 2025?

Solar panels have exploded in popularity across the UK as homeowners look for ways to cut electricity bills. But one question keeps coming up: should you add a solar battery to your system?

A solar battery lets you store excess energy generated during the day and use it at night — making your home less reliant on the grid. But with costs ranging from £3,000 to £6,000, many people are asking: are solar batteries really worth it in 2025?

In this guide, we’ll explain what solar batteries are, how they work, what they cost, the savings they offer, and whether you should invest in one this year.

What Is a Solar Battery?

A solar battery is an energy storage system that captures surplus electricity generated by your solar panels. Instead of exporting unused power to the National Grid, you can keep it in the battery and use it when you need it.

  • Daytime – Panels generate electricity, your home uses what it needs, and excess is stored.

  • Evening/Night – Stored power runs your appliances, reducing reliance on grid electricity.

  • Peak Tariffs – Some batteries let you store cheap off-peak electricity (Economy 7 / Agile tariffs) and use it during expensive peak hours.

Modern solar batteries use lithium-ion technology (like EV batteries), offering long lifespans and fast charging.

How Much Do Solar Batteries Cost in 2025?

Solar battery costs have come down over the past decade but still represent a major investment.

  • Small battery (3–5kWh): £2,500–£4,000

  • Medium battery (6–10kWh): £4,500–£7,000

  • Large battery (10–15kWh): £7,000–£10,000

Factors that Affect Cost:

  • Battery size (measured in kWh storage capacity).

  • Brand (Tesla Powerwall, LG Chem, GivEnergy, Huawei, etc.).

  • Whether it’s installed alongside solar panels or retrofitted.

  • Additional hardware (inverters, monitoring systems).

How Long Do Solar Batteries Last?

Most solar batteries last 10–15 years, depending on usage and brand.

  • Cycle life: Each charge/discharge counts as one cycle. Most batteries are rated for 5,000–6,000 cycles.

  • Warranties: Leading brands like Tesla offer 10-year performance warranties, guaranteeing at least 70–80% capacity after a decade.

This means a solar battery installed today could easily last until the mid-2030s, often matching the lifespan of your solar inverter.

How Much Can You Save with a Solar Battery?

The savings depend on your household energy usage, solar panel size, and electricity tariff.

Without a Battery:

  • You use solar power during the day.

  • Excess electricity is exported to the grid (you earn SEG payments, usually 5–15p per kWh).

  • At night, you pay for grid electricity (28–35p per kWh in 2025).

With a Battery:

  • You store surplus energy instead of exporting it.

  • Evening usage is powered by free stored electricity.

  • You reduce expensive peak-time imports.

  • Some batteries allow smart charging — storing cheap off-peak grid electricity.

Typical Savings:

  • Average household with 4kW solar panels + 8kWh battery:

    • Bill reduction: £700–£1,100 per year

    • SEG payments reduced (since you’re exporting less)

    • Net gain: £500–£900 per year compared to solar without battery

Payback Period:

  • Typical solar-only system: 7–10 years ROI.

  • Solar + battery system: 10–15 years ROI (shorter if energy prices rise).

Are Solar Batteries Eligible for Grants in 2025?

At the moment, there is no direct government grant for solar batteries alone. However, there are ways to reduce costs:

  • ECO4 Scheme – In some cases, low-income households may qualify for free solar + battery installations if it improves EPC ratings.

  • Local Authority Schemes (HUG2) – Certain councils include solar + storage in energy efficiency upgrades.

  • VAT Relief – As of 2023, solar panels and batteries installed together are zero-rated for VAT, saving 20%.

Advantages of Solar Batteries

  • Maximise Solar Usage – Use up to 80–90% of generated electricity instead of 40–50%.

  • Lower Bills – Reduce expensive peak-time imports.

  • Energy Independence – Less reliance on volatile energy suppliers.

  • Backup Power – Some batteries (Tesla Powerwall) can act as backup during outages.

  • Future-Proof – Pairs well with electric vehicle charging.

Disadvantages of Solar Batteries

  • High Upfront Cost – £3,000–£7,000 investment.

  • Longer ROI – 10–15 years, depending on usage.

  • Degradation – Capacity reduces over time.

  • Not Always Necessary – If you’re at home during the day, you may already use most of your solar power.

Are Solar Batteries Worth It in 2025?

The answer depends on your household circumstances.

Worth It If:

  • You use most of your electricity in the evening/night.

  • You have a large solar system (4kW+).

  • You’re on an expensive time-of-use tariff.

  • You plan to stay in your home long-term.

  • You own (or plan to buy) an electric vehicle.

Less Worth It If:

  • You’re home during the day (so you already use most solar power).

  • You have a small solar system.

  • You plan to move house within 5 years.

Real-World Example

  • Household A installs 4kW solar panels (£6,500) without battery:

    • Saves £700 annually on bills.

    • Payback period: 9 years.

  • Household B installs 4kW solar + 8kWh battery (£12,000 total):

    • Saves £1,200 annually on bills.

    • Payback period: 10–11 years.

In this case, the battery adds independence and long-term resilience but extends payback slightly.

The Future of Solar Batteries in the UK

Solar batteries are expected to become even more popular in the next decade.

  • Falling prices as technology improves.

  • Larger capacities designed for EV charging.

  • Smarter batteries that trade energy back to the grid at peak prices (“vehicle-to-grid” systems with EVs).

  • Growing importance as the UK moves to a net-zero energy system.

By 2030, most new solar systems are expected to include battery storage as standard.

Conclusion

Solar batteries are not essential for every UK household, but in 2025 they’re increasingly seen as a smart investment. While the upfront cost is high, the benefits — from lower bills to energy independence and increased property value — can make them worthwhile.

If you’re considering solar panels, adding a battery is often best done at the same time to take advantage of zero VAT installation and maximise your savings from day one.

👉 Check your eligibility today to see if you can access funding for solar panels and batteries, and get free quotes from accredited installers.