More people in the UK are pairing solar panels with battery storage so they can use more of their own electricity, cut bills further, and have backup power when they need it. But one of the most common questions we hear is simple: what size solar battery do I need in the UK?
The answer depends on how much energy you use, the size of your solar panel system, and how much you’d like to lower your reliance on the grid.
At Bolton Electrical Services, we specialise in fitting the right solar panel and battery setups for homes and businesses across Bolton and the North West, making sure every system is designed around real energy needs rather than guesswork.
Understanding Solar Battery Sizes
How Big Are Solar Panel Batteries?
When people ask how big a solar battery is, they’re usually talking about its storage capacity rather than its physical size.
Most domestic solar batteries in the UK fall in the range of 4kWh to 10kWh, which is usually enough to cover a good portion of a household’s evening and overnight energy use.
Larger properties or homes with high energy demand may benefit from systems above 10kWh.
For businesses and commercial buildings, the scale is bigger. Commercial batteries often start at 20kWh and can go into the hundreds of kWh, depending on how much backup power and grid independence the organisation is aiming for.
In terms of physical space, modern batteries are compact and wall-mounted. A domestic unit is typically about the size of a large suitcase, while commercial systems may be rack-mounted but still designed to fit neatly into existing plant rooms or storage areas.
How Solar Battery Capacity Is Measured
Solar batteries are measured in kilowatt-hours (kWh), which tells you how much energy they can store and release. To put that into context:
- A 5kWh battery could keep a fridge, a few lights, and a laptop running for around 24 hours.
- A 10kWh battery might power an average home’s evening use, including lights, appliances, and TV, until the next morning.
Of course, the exact runtime depends on your usage, but thinking in kWh makes it easier to match battery size to your lifestyle or business operations.
What Size Solar Battery Do I Need?
Factors That Determine the Right Battery Size
The size of solar battery you need depends on how much electricity you use and what you want from your system. Daily energy consumption is the biggest factor, but we also look at how many solar panels you have and how much they generate.
If your goal is simply to cover evening usage, a smaller battery may be enough. If you want full self-sufficiency or backup power during outages, you’ll need more storage capacity.
Typical Solar Battery Sizes for UK Homes
For most UK homeowners, a solar battery sits somewhere between 3kWh and 10kWh. Smaller homes may only need around 3–5kWh, which is enough to keep essential appliances running after sunset.
An average family household often benefits from a 5–10kWh system, balancing cost with performance. Larger homes with higher demand, or those adding battery storage for electric vehicle charging, may find that 10kWh or more gives them the flexibility they need.
Solar Batteries for Businesses in the UK
Commercial properties usually need bigger, modular systems that can be scaled as energy demand grows.
Businesses often install 20kWh batteries or larger to cover their needs, with some systems going into the hundreds of kWh.
At Bolton Electrical, we specialise in designing and installing commercial solar battery solutions tailored to each organisation. Whether it’s an office, school, warehouse, or retail space, we make sure the system matches the building’s energy profile and long-term goals.
Benefits of Choosing the Right Solar Battery Size
Maximise Solar Energy Use
When your battery is the right size for your property, you can store more of the electricity your panels generate instead of sending it back to the grid.
This means you make the most of your investment in solar power and rely less on buying energy from your supplier.
Protect Against Rising Energy Costs
Energy prices in the UK have become unpredictable, and a correctly sized solar battery helps you avoid expensive peak rates.
By storing power during the day, you can use it in the evening when demand – and tariffs – are often higher. This keeps your bills lower and gives you more control over your energy use.
Backup Power Security
Some solar batteries provide backup in the event of an outage, depending on the system design.
Whether it’s keeping the lights on at home or making sure your business can continue running key equipment, battery storage with backup abilities provides a reliable safety net, so if this is something you require, it’s important to check that the battery you choose is capable.
Bolton Electrical Services: Expert Solar Panel Battery Installation
Tailored Advice on Battery Sizes
At Bolton Electrical Services, we know that no two properties use energy in the same way. That’s why we offer a free consultation to look at your energy needs, daily usage, and long-term goals before recommending the right battery size.
Our advice is always tailored, so you only pay for the storage capacity you’ll actually benefit from.
End-to-End Installation and Support
We provide the full package: from initial design and planning, through to installation, servicing, and upgrades when your needs change.
Our engineers make sure your system is fitted to the highest standards and works seamlessly with your existing solar setup. We also offer ongoing support to keep your battery system running at peak performance.
Frequently Asked Questions (FAQ)
What size solar battery do I need in the UK?
For most UK homes, batteries between 5–10kWh are suitable, but the exact size depends on your daily energy use, how many solar panels you have, and whether you want backup power.
How big are solar panel batteries?
Domestic solar batteries usually range from 3–15kWh. For businesses, larger modular systems can be installed to meet higher demand.
How much battery storage do I need for my home?
It depends on how much electricity you use each day and whether you want to cover evening use, backup power etc. If your goal is to rely less on the grid or cover most of your usage, larger batteries are needed.
What size battery is best for solar panels with 10 panels?
Many 10-panel systems (3.5–4kWp) work efficiently with a 5–8kWh battery, but the right size depends on daily usage.
Are bigger solar batteries always better?
Not necessarily. Oversizing can increase costs without delivering extra savings if you don’t use all the stored energy. The goal is to match the battery to your actual usage.
Can I add more batteries later?
Yes. Many modern battery systems are modular, meaning you can expand storage capacity in the future as your energy needs grow.
