Information Notice
This guide compiles information from manufacturer specifications, industry publications, and installer data. We are an independent information service, not battery installers. Always consult MCS-certified installers for advice specific to your property and existing solar system.
How Solar Batteries Work
A solar battery stores surplus electricity generated by your solar panels during the day, so you can use it in the evening and at night when the panels are no longer generating. Without a battery, any electricity you do not use immediately is exported to the grid.
According to the Energy Saving Trust, a typical household without a battery might use only 50-60% of the solar electricity generated. Adding a battery can increase self-consumption to 80% or more, significantly reducing the amount of electricity you need to purchase from the grid.
Most home batteries use lithium-ion technology, the same chemistry found in electric vehicles. They are compact, wall-mounted units typically installed in a garage, utility room, or on an exterior wall.
Solar Battery Costs
| Capacity | Typical Cost | Suited To | Evening Coverage |
|---|---|---|---|
| 3-5kWh | £2,500-£3,500 | Small households, low evening usage | A few hours of typical use |
| 5-8kWh | £3,500-£5,000 | Average households, moderate evening usage | Most of an evening for typical homes |
| 10-13.5kWh | £4,500-£6,000 | Larger households, high evening usage, EV owners | Full evening and overnight for many homes |
Source: Compiled from installer pricing data and manufacturer RRPs, 2026. Costs include installation. Batteries for residential use attract 0% VAT when installed with solar panels (HMRC).
Benefits of Solar Battery Storage
Increased Self-Consumption
According to the Energy Saving Trust, adding a battery can increase the proportion of solar electricity you use directly from around 50-60% to 80% or more, reducing grid purchases.
Time-of-Use Tariff Savings
Some energy tariffs charge different rates at different times of day. A battery lets you charge from the grid at cheap overnight rates and use stored energy during expensive peak hours.
Backup Power
Some battery systems offer backup power during grid outages. According to manufacturers, not all batteries include this feature, so check specifications if this is important to you.
When Does a Battery Make Financial Sense?
Strong Case for a Battery
- You use most electricity in the evening and at night
- You have access to a time-of-use tariff with large peak/off-peak differences
- You are installing solar panels anyway (adding a battery at the same time is cheaper)
- Backup power during outages is important to you
Weaker Case for a Battery
- You work from home and already use most solar electricity during the day
- Your electricity usage is very low overall
- You are on a flat-rate tariff with no peak/off-peak difference
- Budget is tight and solar panels alone would give better return on investment
Check Your Battery Storage Eligibility
Some households may qualify for subsidised energy storage installation through government schemes. Check your eligibility.
Key Eligibility Factors:
- Low-income household
- Property EPC rating D-G
- Owner-occupier or private tenant
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Battery Installation Process
Assessment
An installer reviews your solar system, electricity usage patterns, and available space for the battery unit.
Sizing
The installer recommends a battery capacity based on your solar generation, usage patterns, and budget.
Installation
Battery installation typically takes half a day to a full day, depending on the system and whether it is retrofitted or installed alongside new panels.
Commissioning
The installer configures the battery management system, sets charge schedules, and shows you how to monitor performance.
Related Guides
Solar Panels Guide
Complete introduction to solar panels, how they work, and panel types available.
Read guideSolar Panel Costs
Detailed cost breakdown by system size, with payback period analysis.
See costsBattery Storage Guide
In-depth guide to home battery storage technology, types, and specifications.
Read guideReady to Add Battery Storage?
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