How do solar batteries work?
A solar battery stores the surplus electricity your panels generate during the day so you can use it in the evening instead of buying from the grid. This lifts the share of your own solar you use from around 37% to roughly 70%. Home batteries hold 5 to 13 kWh, cost £2,500 to £6,000, and are typically warrantied for around 10 years.
How a battery fits in
- Panels charge the battery once the home's live demand is met.
- In the evening, the home draws from the battery before the grid.
- A hybrid inverter manages the flow between panels, battery, home and grid.
- On a smart tariff, the battery can also charge cheaply overnight.
Why batteries improve savings
Because imported electricity (around 27p per kWh) costs nearly twice what exported energy earns (around 15p), storing your surplus to use yourself is worth more than selling it. This is why a battery often improves payback for homes that are empty during the day.
Frequently asked questions
- How long does a solar battery last?
- Most are warrantied for around 10 years and retain a large share of capacity over that time.
- Can I add a battery to existing solar?
- Yes. An AC-coupled battery can be added to an existing system, though fitting a hybrid inverter from the start is tidier if you know you want storage.
Related questions
Indicative estimates based on UK average data. Last updated 27 May 2026.