Keep it close to your solar panels if you can

It's best to keep a storage battery near your consumer unit (fuse box), as it loses energy as it moves through the house. But some can be noisy, so think about where it will go in your house that won't bother you.

Don't let it overheat

Don't let it overheat, as it can become inefficient, and reduce its lifespan, meaning you'll need to replace it sooner than planned. There's also a chance a solar battery can cause a fire if it overheats. Try to keep your battery in a cool, shaded spot in your house, and consider a cooling system if overheating is likely.

Consider what power output you need

You need to consider the power output of a battery, as that's what will enable you to power all the appliances in your home. The output of a battery – measured in kilowatts (kW) – is how much energy it can provide at any given time. Having a huge storage capacity is only part of the equation, you need to ensure its output is sufficient for your needs.

Get one with a larger capacity if you're planning on getting a heat pump or EV

You should get a battery with a larger capacity if you're planning on getting a heat pump or an electric car with a home charger, as these will increase your home's energy consumption so you may want a battery with a larger capacity to be able to store energy to power these.

Which type of battery you get will depend on when you're installing it

If you're installing a solar battery at the same time as solar panels, it's best to opt for a DC battery, which connects directly to your panels and doesn't require an additional inverter. However, if you already have solar panels, you'll need an AC battery, which is much easier to retrofit to an existing system. It's connected via your electricity meter, but it does require an additional inverter – so bear that in mind when budgeting the costs.

Your battery's efficiency may change with the seasons

In the colder months, you may need to keep the amount of energy stored in your battery at a higher level compared with the summer. That's because your battery won't work as efficiently when it's cold.

It's possible to have a solar battery without solar panels

It's possible to have a solar battery without solar panels, but it'll mean you're still relying on – and paying for – electricity from the national grid. But you could pair it with a time-of-use tariff that offers cheaper electricity at certain times of day, which you could use to charge your battery and use when the grid costs more. However, it may take a while to break even on the cost of the battery. See our Economy 7 and EV tariffs guides for more info on time-of-use tariffs. Alternatively, you could have a domestic wind turbine installed in your garden, and use a battery to store the energy its generates.

Solar storage batteries don't last as long as solar panels so will need replacing sooner

Solar batteries generally only last five to 15 years, compared with a 25-year life span of solar panels, so you'll likely need to replace your battery during the lifetime of your solar panels.

A solar storage battery is not the same as a solar power battery bank

You can get smaller, more basic, portable versions of solar power batteries, but these are unlikely to enable you to power your whole home using the sun. A solar battery charger – or a solar battery bank – is made up of mini foldable solar panels that hook up to a battery. You can then plug in and power devices such as smartphones, TVs and laptops through the battery's USB ports.

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Is solar battery storage worth it?

Clare Casalis | Edited by Andrew Capstick

Updated 4 September 2024

A solar battery allows you to store electricity produced by your solar panels and use it later or, in some cases, sell it back to the grid to make a few quid – but they're not cheap. Read on to see if it's worth getting a solar storage battery for your home...

This is the first incarnation of this guide. We'd love to know your thoughts and experiences with solar batteries, or if you've any feedback or questions we've not answered. Let us know in the Is solar battery storage worth it? forum thread.

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What is a solar battery?

Solar batteries are designed to work with solar panel systems. It's a device that stores the electricity you generate (but don't use immediately) from your solar panels, allowing you to then use that electricity later in the day.

It's a bit like portable power packs that you can charge your mobile phone with when you're out and about – only a solar battery is much much bigger (and less portable). You charge it up using your solar panels, and then use it to power your home, instead of using power from the grid.

A solar panel battery costs around £5,000

Solar batteries vary in price, depending on the type and storage capacity (how much energy it can hold). The cheapest start at around £1,500, but can be as much as £10,000 – though on average, you'll typically pay around £5,000 for a standard battery system.

Bear in mind, when getting a solar battery, you'll have to factor in installation fees and the cost of adding an inverter to your system. Despite the hefty price tag, once installed, solar power batteries require little maintenance. However, they will have a shorter life span than solar panels, lasting anything from five to 15 years.

With energy prices still sky-high – see our Should you fix energy? guide for the latest on the energy market – many are looking at solar and solar batteries as a way to cut costs. Below we take you through what you need to consider.

How does your system decide when to use, store or export the electricity generated by your solar panels?

Your inverter is what powers your appliances. It has three sources of energy: your solar panels, your battery or the grid – and it'll use it in that order. So by default, any electricity your solar panels generate will be used to power your home, and then used to charge your storage battery.

Any unused electricity is exported back to the grid when your battery is full, or when you schedule it to (which you may want to do, as some energy companies will pay you more for exporting electricity at peak times).

If you're using an energy-guzzling appliance such as a washing machine, even on a mostly sunny day, the appliance will often draw more energy than your solar panels are producing at that moment. If you have a battery, it'll draw the extra power needed from that rather than the grid (assuming you have power already stored).
How do solar batteries work?

Put simply, when sunlight hits the cells in your solar panels, it creates a direct current (DC) of electricity, which is then stored in your battery (solar batteries can only store DC electricity).

Yet your household appliances use an alternating current (AC) to power them, so in order to use the electricity generated by your solar panels, it first needs to convert the DC electricity to AC. This is done using an inverter.

If you're installing a solar battery at the same time as solar panels, it's best to opt for a DC battery, which connects directly to your panels and doesn't require an additional inverter. However, if you already have solar panels, you'll need an AC battery.

When your house requires more electricity than your solar panels are generating (for example, during the night or on cloudy days), the stored energy in your battery kicks in.

If you're signed up to the Smart Export Guarantee, you can also convert the DC electricity stored in your battery into AC electricity to be sold back to the grid.
How do you use the energy your battery has stored?

Your battery is always connected to the national grid, but your home will automatically use the power stored in your battery before it draws electricity from the grid. Once the energy stored in your battery is used up, your home will once again be powered by the grid.

Most modern storage batteries allow you to monitor your electricity generation and storage via an app or through an online account – some even let you access your system remotely and decide which devices you want your battery to power. These apps and online accounts are usually managed by the company who provided your inverter.
Batteries are stored inside your home

Your solar panel battery should be kept indoors and fairly close to your main consumer unit (sometimes known as a fuse box or fuse board). This way it'll reduce the length of the connecting cables and minimise energy loss. Some solar power batteries can be wall-mounted (weight-dependent), otherwise they just sit on the floor.

The most common places for a solar panel battery to be installed are in cupboards, garages, utility rooms or loft space. It should also be kept in a well-ventilated place and out of direct sunlight to prevent damage. Plus, it needs to be easily accessible in case it needs any maintenance or repairs in the future.

You'll also need to bear in mind whether you'll want to add more batteries at a later date – if so, you need to make sure there's enough space to do so.
You won't pay any VAT on solar batteries until 2027

From 1 February 2024, you won't pay any VAT on batteries for solar panels (previously you had to pay 20% VAT, unless you bought it as part of a solar panel system). So now you can install a standalone energy storage battery or add one to your existing solar PV system, and you'll pay 0% VAT. From 1 April 2027, this is set to increase to 20% VAT.

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Is it worth getting a storage battery with solar panels?

In order to answer this, there are some key points you need to consider before buying a solar battery:

Solar batteries come with a hefty upfront cost. The actual cost will depend on your home and the size of the battery you want or need, but it can range between £1,000 and £10,000.
You'll likely need two batteries during the life of your solar panels. Batteries last around 15 years, while solar panels last about 25 years.
Consider if you'll recoup the costs over the life of your solar panels. As an example, if a £5,000 battery lasts 15 years, you need to be saving about £330 a year to break even. And that's just for the battery, you also need to bear in mind the solar panels maths.
It's usually cheaper to use stored energy than get paid to export it. Under the Smart Export Guarantee (SEG) scheme, you get paid for each unit of electricity you don't use and export back to the grid. However, under the SEG, the cheapest open-market rate is 16.5p/kWh of electricity you export. Yet on average, it costs 22.4p/kWh (if you pay by Direct Debit) under the Energy Price Cap to use energy from the grid.

So right now, it's better to use your stored electricity, rather than selling what you don't use, as buying from the grid will generally cost you more than you can earn from selling it. But if you already have a SEG tariff, bear in mind your income from this will fall if you get a battery.
Some suppliers do pay more under the SEG if you export at certain times of the day, or if you get your solar panels installed by the SEG provider – see our full list of SEG tariffs. So in some cases, it might actually be better to export than to store.
You'll be able to use more of the electricity you generate. This should reduce your energy bills – and your carbon footprint. For example, if you're not at home during the day to use the energy your solar panels are generating, having a battery will enable you to store (and later use) energy from your solar panels.
A solar battery means you can take advantage of cheaper electricity. There are now special energy tariffs available if you have solar panels and a solar battery, which offer much cheaper rates for electricity at off-peak times (usually for a few hours overnight).

By charging your battery (from the grid) during off-peak times when it's cheaper and storing the energy, you can use it when electricity from the grid is at its most expensive – potentially saving you £100s on your electricity bill each year.
You could charge your EV for free. If you're an electric vehicle owner, you can use your solar battery as a car charger. Any electricity generated from your panels can be stored in your solar battery to then charge up your EV overnight.

So is it worth getting a solar battery?

It's incredibly difficult to quantify whether a solar battery will be worth it, as every household has different energy usage patterns.

According to The Eco Experts, a typical three-bedroom home could save around £582 every year with a solar battery AND solar panel system. Yet most of this saving will come from the solar panels. Only around £130 a year is saved by using stored energy in your battery.

As solar batteries come with a huge upfront cost, and the extra savings are relatively small, most will be unlikely to recoup the cost of buying a battery over its lifespan – though of course, it depends on the cost of the battery, the price of electricity and how you use it.

However, solar batteries are a great way of maximising the electricity generated by your solar panels, and reducing your reliance on the national grid, which does make it an environmentally-friendly addition to your home.

If your primary motivation for getting a solar battery is to save money, it may not be worth it until the price of solar batteries comes down (which it should, as the technology evolves and improves), or if the price of electricity rises steeply.

Ask a solar panel installer to give you an estimate of the amount you may be able to save on your energy bills, with and without a battery, to help you work out whether the additional expense is worth it. Though do bear in mind, installers may have a vested interest in wanting to upsell you a battery.

If you get Feed-in-Tariff payments, check with your supplier before installing a battery

If you currently get Feed-in-Tariff (FIT) payments, Ofgem recommends you contact your energy supplier before relocating or installing batteries, as this can affect your FIT payment eligibility.

What size solar battery will I need?

When working out what solar battery size you require, the main thing for you to consider is how much energy your solar panels produce and how much energy your household uses.

You ideally want a battery big enough to store the electricity you generate but don't use, but at the same time it's not worth buying one that you can never fill.

A solar panel system typically generates double its 'size'. For example, a standard '4 kilowatt peak' (kWp) solar panel system could generate around 8kWh of electricity in a day (weather-dependent). Therefore, you'd want a battery that has a maximum capacity of 8kWh to store all the energy your solar system could potentially produce.

Yet you also need to consider how much energy you use each day. The ideal situation is that – between the solar panels and battery – you generate and store enough to completely cover your daily use. For that, you'd also need a battery that's big enough to cover your daily use.

Of course, this isn't always possible – particularly if you're at home during the day and using most of the electricity your solar panels generate. If that's the case, you may want to consider a smaller battery.

Consider how much of the stored energy you can actually use

Battery sizes are measured by how much solar electricity they can store, but generally, you shouldn't fully drain a battery, as it can damage it, meaning it'll likely need replacing sooner.

Most modern batteries allow you to use 85% and 95% of the energy stored. So you'd expect a 8kWh battery to have a usable capacity of between 6.8kWh and 7.6kWh. You'll also need to factor this in when choosing which battery size to get.

But bear in mind, the larger the storage capacity, the pricier it is, so make sure you get proper advice from a reputable installer, as the type and size of battery you need will depend on individual circumstances, property type, and what'll you'll be using it for.

It's cheaper if you install a solar battery and solar panels at the same time

It's typically cheaper to set up your solar battery at the same time as installing your solar panels as you can often get a better price for the whole package, plus you won't need to pay for an engineer to come out twice.
Can I add more batteries at a later date?

Yes, in many cases, batteries can be coupled together to provide more storage. So if you find you're still exporting more energy than you expected, you can add extra batteries as needed. If you think you'll need more storage capacity in future, make sure you buy a system that allows you to add extra solar power batteries.
You can work out what size battery you need by working out how many kilowatt hours (kWh) your home uses each day.

If you want to be more mathematical about it, you can work out what size battery you need (or if you need more than one battery) by working out how many kilowatt hours (kWh) your home uses each day, and how much electricity your solar panel system generates.

You should be able to check this fairly easily with a smart meter, or by looking at your energy bills (solar panel surveyors will typically get a year's worth of your energy bills and divide the total electricity consumption by 365 to get an average daily use).
You don't necessarily need a battery big enough to cover ALL your usage

It's worth remembering, you don't necessarily need to buy a big enough battery to cover all of your daily usage – you'll still be connected to the grid if there's a shortfall.

And if you do generate more electricity than your battery can hold, that electricity will still be exported back to the grid (which you can get paid for under the Smart Export Guarantee).

How to find the right solar battery installer

When choosing and installing a solar battery storage system, make sure your installer is signed up to the Renewable Energy Consumer code (RECC) or the Home Insultation and Energy Systems Contractor Scheme (HIES), as this means you'll be covered should you need to make a complaint or claim.

Installers who are signed up to one of these schemes should be certified by the Microgeneration Certification Scheme (MCS) – an accreditation scheme for renewable energy installers and products.

If you want to be able to sell your excess power back to the national grid through the Smart Export Guarantee (SEG) scheme, your system must be certified by MCS. You can find an MCS certified battery storage installer on the MCS website.

Not got solar panels yet? See how to find certified solar panels installers.

Part pay with a credit card if you can

If you don't have the cash upfront, then a solar storage battery might not be right for you – they're a long-term investment, so any savings you make on your energy bills will be negated if you're paying loan interest.

However, if you part-pay for the battery on your credit card (even just £1), you get full Section 75 consumer rights protection, meaning by law the lender's jointly liable with the retailer. So if the retailer goes bust, you can simply take your complaint to your credit card provider instead. This is not the case if you pay with debit card, cheque or cash. See our Section 75 guide for a full explanation.

However, if paying by debit card, there's also valuable hidden protection that means you may be able to get your money back if something goes wrong. It's called 'chargeback' and applies to most debit and charge cards, as well as Visa, Mastercard and American Express credit cards – though it isn't a legal requirement. See our Chargeback guide.
How to get help if things go wrong

Step 1: Speak to your installer

If you experience problems with your new solar battery, such as performance issues, faults, or safety concerns, the first thing to do is speak to your installer, as your battery should come with a warranty.

Send a formal complaint to the installer who carried out the work. They have 14 days from receiving your letter to resolve the issue.

Step 2: Get help from the Microgeneration Certification Scheme

If your installer is part of the Microgeneration Certification Scheme (MCS), you can get help from the MCS – it has a list of what issues are covered by the scheme. You'll then need to complete and submit its "Something's Gone Wrong" form.

If you haven't heard back from MCS within five working days, get in touch with them. You can call the MCS helpdesk on 0333 103 8130 or email it.

There are special energy tariffs available if you have a solar panel battery

If you have a solar battery, Octopus Energy has two innovative tariffs that can beat most of the SEG rates – but they're complex.

Octopus Flux and Intelligent Octopus Flux are tariffs for existing Octopus customers with solar panels and storage batteries (although you can switch to Octopus' standard variable tariff first if you're not already a customer).

Both are import and export tariffs, meaning you'll pay for any electricity you use and it'll pay you for any power you send back to the grid. To get 'em, you'll also need a working smart meter and battery (and a particular kind of battery with Intelligent Octopus Flux). You can read more about these tariffs in our Solar panels guide.

You can set your battery to export electricity at certain times of day

With tariffs such as Octopus Flux, you can set your system to charge your battery overnight (from the grid) when rates are cheapest, then export electricity in the early evening, when export rates are highest. The Intelligent Octopus Flux does this for you automatically, but it's only compatible with one type of battery right now.

Top tips when getting a solar battery

1. Keep it close to your solar panels if you can

It's best to keep a storage battery near your consumer unit (fuse box), as it loses energy as it moves through the house. But some can be noisy, so think about where it will go in your house that won't bother you.
2. Don't let it overheat

Don't let it overheat, as it can become inefficient, and reduce its lifespan, meaning you'll need to replace it sooner than planned. There's also a chance a solar battery can cause a fire if it overheats. Try to keep your battery in a cool, shaded spot in your house, and consider a cooling system if overheating is likely.
3. Consider what power output you need

You need to consider the power output of a battery, as that's what will enable you to power all the appliances in your home.

The output of a battery – measured in kilowatts (kW) – is how much energy it can provide at any given time. Having a huge storage capacity is only part of the equation, you need to ensure its output is sufficient for your needs.
4. Get one with a larger capacity if you're planning on getting a heat pump or EV

You should get a battery with a larger capacity if you're planning on getting a heat pump or an electric car with a home charger, as these will increase your home's energy consumption so you may want a battery with a larger capacity to be able to store energy to power these.
5. Which type of battery you get will depend on when you're installing it

If you're installing a solar battery at the same time as solar panels, it's best to opt for a DC battery, which connects directly to your panels and doesn't require an additional inverter.

However, if you already have solar panels, you'll need an AC battery, which is much easier to retrofit to an existing system. It's connected via your electricity meter, but it does require an additional inverter – so bear that in mind when budgeting the costs.
6. Your battery's efficiency may change with the seasons

In the colder months, you may need to keep the amount of energy stored in your battery at a higher level compared with the summer. That's because your battery won't work as efficiently when it's cold.
7. It's possible to have a solar battery without solar panels

It's possible to have a solar battery without solar panels, but it'll mean you're still relying on – and paying for – electricity from the national grid. But you could pair it with a time-of-use tariff that offers cheaper electricity at certain times of day, which you could use to charge your battery and use when the grid costs more.

However, it may take a while to break even on the cost of the battery. See our Economy 7 and EV tariffs guides for more info on time-of-use tariffs.

Alternatively, you could have a domestic wind turbine installed in your garden, and use a battery to store the energy its generates.
8. Solar storage batteries don't last as long as solar panels so will need replacing sooner

Solar batteries generally only last five to 15 years, compared with a 25-year life span of solar panels, so you'll likely need to replace your battery during the lifetime of your solar panels.
9. A solar storage battery is not the same as a solar power battery bank

You can get smaller, more basic, portable versions of solar power batteries, but these are unlikely to enable you to power your whole home using the sun.

A solar battery charger – or a solar battery bank – is made up of mini foldable solar panels that hook up to a battery. You can then plug in and power devices such as smartphones, TVs and laptops through the battery's USB ports.

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