Solar Battery Storage Guide 2026
Battery storage transforms a good solar investment into a great one. Store surplus energy, eliminate export at low rates, and keep your lights on during power cuts.
Why Add Battery Storage to Solar?
A solar panel system without battery storage exports surplus electricity to the grid at low SEG rates (typically 3–15p/kWh) and then buys electricity back in the evening at full retail price (24–28p/kWh). A battery closes this gap by storing your own solar electricity for use when the sun is not shining.
With a battery, a typical 4kW solar system with 9.6kWh storage can achieve 80–90% self-sufficiency throughout summer months. The additional cost of a battery is typically recovered in 5–7 years through avoided import costs.
Solar Without Battery vs Solar With Battery
| Solar Without Battery | Solar With Battery |
|---|---|
| Surplus exported at 3–15p/kWh | Surplus stored for evening use |
| Evening power purchased at 24–28p/kWh | Very little evening grid import |
| Self-consumption: 30–50% | Self-consumption: 80–90% |
| Lower upfront cost | Backup power in outages (some models) |
Battery Comparison 2026
All prices include installation and 0% VAT. Supplied and installed by Midland Solar.
| Battery | Capacity | Max Power | Warranty | Installed Price | Notes |
|---|---|---|---|---|---|
| Fox ESS EP5 | 9.5kWh | 5kW | 10 years | £3,800–£4,800 | Best value for most homes |
| Tesla Powerwall 3 | 13.5kWh | 11.5kW | 10 years | £8,500–£10,000 | Premium — ideal for EV owners |
| Fox ESS ECS2900 | 9.6kWh | 3kW | 10 years | £3,200–£4,200 | Reliable, competitive pricing |
| SIG Energy | 10kWh | 5kW | 10 years | £3,500–£4,500 | Excellent UK-supported system |
| Solis RHI-3P | Up to 20kWh | 10kW | 10 years | £5,000–£8,000 | Ideal for larger homes |
How to Choose the Right Battery Size
| Household | Daily usage | Recommended battery | Ideal solar |
|---|---|---|---|
| 1–2 people | 6–8 kWh/day | 5–9.6 kWh | 3–4 kW |
| 3–4 people | 10–14 kWh/day | 9.6–14.4 kWh | 4–6 kW |
| 5+ people | 15–20+ kWh/day | 14.4–20 kWh | 6–10 kW |
Frequently asked questions
How much does a home battery storage system cost in the UK?
Home battery storage systems typically cost between £2,500 and £10,000 in the UK, depending on capacity. A 9.6kWh Fox ESS battery costs approximately £3,500–£4,500 installed. A 14.4kWh system costs £4,500–£6,500. When combined with a solar installation, batteries often attract package discounts.
How long does a home battery last?
Most modern home batteries are rated for 6,000–10,000 charge cycles and come with 10-year warranties. In normal use (one full charge-discharge cycle per day), this equates to 16–27 years of service life. In practice, batteries typically last 12–15 years before needing replacement.
What size battery do I need?
The right battery size depends on your daily energy consumption and solar system size. For a typical UK home using 10–15 kWh per day with a 4kW solar system, a 9.6–14.4 kWh battery is usually sufficient to store the surplus from a sunny day. We size batteries precisely to your usage pattern during our survey.
Can I add battery storage to an existing solar system?
Yes — battery storage can be retrofitted to most existing solar installations. Depending on your current inverter, we may need to install a hybrid inverter alongside the battery. Midland Solar installs battery storage retrofits regularly and can assess compatibility with your existing system.
Do battery storage systems qualify for 0% VAT?
Yes — since February 2024, standalone battery storage systems (without solar panels) qualify for 0% VAT when installed in a residential property. Previously, the 0% rate only applied to batteries installed alongside solar panels. This has made battery-only retrofits significantly more cost-effective.
Which battery is best — Tesla Powerwall or Fox ESS?
Both are excellent systems. The Tesla Powerwall 3 is premium-priced but integrates with Tesla EVs and solar exceptionally well. Fox ESS offers excellent performance at a competitive price point. We recommend the right system for your needs during your free survey.
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