As electricity prices in the UK continue to rise every year, homeowners are turning to renewable energy solutions to reduce costs and improve their energy efficiency. One solution is to purchase solar batteries and install them alongside your solar panel system. This article examines the value of installing solar batteries in the UK, discussing their benefits, lifespan, capacity, and potential financial savings. We’ll also explore what factors affect the battery size you may need to help you make informed decisions about your energy storage solutions.

Investing in solar battery storage does require upfront costs, which some homeowners can find challenging to cover. While the savings on your monthly bills will eventually pay for your system, you might still wonder if it’s worth the cost.

The short answer is yes. The high rates of electricity prices, amongst some of the highest in the world, make storing your energy in solar batteries much more worthwhile. According to Ofgem, as of April 1, 2025, the average price of electricity in the UK is 27.03p per kilowatt hour (kWh). Smart Export Guarantee (SEG) rates, what you get paid to export the energy you produce back to the grid, vary between 2p and 25.9p. This means most UK residents will save more money storing the solar power they generate than selling it. If you’re on a variable tariff, you’ll save even more using your stored electricity during peak hours.

● Energy independence
● Use more of the solar power you generate
● Long-term financial savings
● Having a battery for backup during a power cut
● Environmental benefits
● Increase the value of your home
● Easy to retrofit into your home if you already have solar panels

A typical solar battery lasts between 5 and 15 years on average. Many of the newer lithium iron phosphate (LiFePO4) batteries are rated 10-15 years or about 4000 cycles, which is the number of times it can be discharged and recharged before you notice a decline in capacity. This means you typically need to purchase them twice within the lifespan of your solar panels, also called photovoltaics, which last 25-30 years. Compared to lead-acid batteries, which max out at only 1800 cycles at most, this will save you significantly since lead models will need to be replaced four or more times during that same period.

Purchase high-quality products with good warranties to ensure a long battery lifespan. For instance, the EcoFlow Power Ocean (Three-Phase) starts at 5kW, is expandable to 45kW, and has 6000 charge cycles. It also comes with a 15-year warranty, so you know it stands by its products.

The size of your photovoltaic system and your consumption determine how much power it can provide each day. Still, a 10kW solar system should provide enough for the average 3-bedroom home. However, this will vary with the season, the type of equipment you have, and your local conditions.

During summer, your system operates at peak performance. A 5kW system will charge quickly after sunrise in the early morning and stay fully charged all day, even with household usage. During the evening, once the sun goes down, it drops to about one-third of its capacity as we continue to use power for cooking, watching TV, etc. We use minimal power during the night, so there will still be some left in the morning, and it will quickly recharge to 100% soon after sunrise.

As you might expect, your system won’t generate as much during the winter since the days are shorter and the sun is less intense. Since the sun also rises later, it will not start charging until after the peak electricity usage in the morning, around 10 am. As your usage falls in the middle of the day, they will reach full capacity by around 2 pm, but they only stay full until around 4 pm when peak usage begins again. Then, they will discharge quickly and fall below 50% during the evening. It will keep supplying power but will be depleted to 20% after midnight. Depending on your battery, this might be its depth of discharge limit, and you will start drawing energy from the grid again.

To determine how many batteries you need to power your home, you need to determine how much electricity you currently use in kWh. You can read this off your smart meter or check your monthly power bill to see how much kWh you consume. Still, the average home will need a 10kW solar system, while a 5kW system may be enough for a small house or flat.

You need to consider the following factors to help determine what size solar battery you need.

How much energy your household consumes is the most critical factor when deciding which size you should get. You can find this on your smart meter or monthly power bills to determine your kWh consumption.

The average UK home uses 2,700kWh per year. Divide that by 365 to find your daily consumption.

2,700kWh / 365 days = 7.4kWh daily

A 5kW model will work if you just want to supplement your grid power, but to supply all of your power, you need a 10kW system.

The amount of power your photovoltaics can produce is another important factor since you should match the size of your array to your storage capacity. There’s no point in installing a large battery if you can never fill it. Your output will also depend on local conditions like sunlight hours, weather, shade, and other factors. Your photovoltaics should come with a monitoring system to allow you to determine how much they produce in a day. If yours is grid-tied, your meter should also allow you to monitor your output. You could consider installing more panels if your daily consumption exceeds your output.

While the goal of energy storage is always to reduce your reliance on the grid, your electricity rates can impact the system you want. Those on flat-rate tariffs will want enough capacity to rely on the grid as little as possible. While those on variable rates will want to ensure their capacity will carry them through peak electricity hours, they may not be concerned about having enough storage to last all night when tariffs are cheaper.

It’s always best to slightly oversize your capacity rather than undersize it since a smaller model may not provide enough energy during power outages or heavy usage. In that case, you would be without power or stuck paying the highest electricity rates. When you have slightly more than you need, you can ensure backup power, greater energy independence, and better cost savings.

The EcoFlow Power Ocean (Single-Phase) starts at 5kW, enough to supplement your grid power for a medium to large-sized home in the UK or provide energy independence for a small house or flat. It’s also easily expandable up to 45kW, which is enough for almost any home to achieve complete energy independence. These systems are also easy to retrofit with your existing photovoltaic array using the EcoFlow Power Ocean DC Fit, which allows you to connect your new batteries between your photovoltaic array and your existing inverter without changing your system. Easy.

A typical three-bedroom home in the UK will save about £669 yearly by not buying as much electricity from the grid. As prices continue to rise this year, your savings will increase further. To calculate your potential savings, estimate your annual savings over the battery’s lifespan and subtract the system's cost.

When deciding whether batteries are worth it, consider the initial purchase cost. Depending on the model and capacity, that ranges between £2,500 and £10,000+.

A complete photovoltaic system with batteries will save you between £450 and £1,020 per year. How much you save depends on your storage capacity, the electricity you consume, and how much you pay for grid electricity.

Everything has downsides, but here, they are few and manageable.

The initial purchase cost is typically considered the most significant downside for the average homeowner, as some may be unable to afford it. However, the long-term savings will make the investment more than worth it.

Maintenance costs used to be higher for lead-acid models, which required regular maintenance and more frequent replacement. Newer LiFePO4 models, like those in the EcoFlow Power Ocean (Single-Phase), require no maintenance and last 2-4 times longer.

The other primary downside is that you'll need to purchase two or more of them within your panels' 25-30-year lifespan. This is why buying high-quality models like the EcoFlow Power Ocean (Three-Phase) is critical. It comes with 6000 charging cycles and a 15-year warranty. Cheaper products that last only 5 years would need replacing 2-4 times more often, costing you far more in the long run.

A typical three-bedroom home will save around £669 yearly with a complete system including panels and batteries. You save money by not buying electricity from the grid and can even make money by exporting electricity to the grid.

Yes. You can store the excess energy you produce during the day and use it during peak tariff hours. Also, even if you exported that energy back to the grid, you usually get paid far less than you pay to buy energy from the grid, especially during peak tariffs.

A 5kW system will run essential appliances and may be enough to run an entire small house or flat. However, your typical 3-bedroom house with average energy needs will need a 10kW system.

Investing in solar batteries is an excellent opportunity for UK homeowners to reduce electricity bills, gain energy independence, and reduce their carbon footprint. While some homeowners may find the initial costs high, the long-term benefits, including about £669 in yearly savings for a typical three-bedroom home, make it a worthwhile investment.

To select the right-sized system for your home, consider your household energy consumption, solar output, and electricity rates to maximise your savings. Then, choose high-quality options like the EcoFlow Power Ocean (Single-Phase)with a 15-year warranty to ensure a reliable and efficient energy storage solution.