Guide to Solar Panel Battery Storage

Overview: What You Need To Know About Solar Panels & Battery Storage

This is a 15-minute guide. Stuck for time? Bookmark our guide to solar panels and battery storage for later, and read this short overview instead!

The average 3-bed in the UK is going to need a 5kWh hour storage battery to be as close to electricity self-sufficient as possible. Expect this to add on around £5,000 to your solar panel installation cost. 

Solar panel batteries tend to last around 10-years, half that of the solar panel system itself. With that in mind, make sure you buy one from a reputable brand that comes with a long warranty. 

The advantages of storage batteries (self sufficiency, protection against rising energy costs, earning an income from selling back to the grid and low maintenance) outweigh the disadvantages (upfront costs and lifespan). 

Whilst storage batteries are expensive, there is funding available via schemes such as: 

• 0% VAT scheme (VAT relief for solar batteries, saving £833.33 on a £5,000 purchase)
• ECO4 grant (free solar panels and batteries for eligible households)
• Smart Export Guarantee (earn money by selling energy back to the grid)

Overall, this makes investing in a solar storage battery a worthy investment. 

You can get prices on-screen for a solar panel system that includes a storage battery by jumping over to our solar panel page here. 

What Size Solar Panel Battery Do I Need?

A typical household in the UK will require a 5kWh solar panel battery. Running a 5kWh battery alongside a solar panel system will ensure that your setup is self sufficient; you won’t need to draw excess electricity from the grid. 

How did we come up with this figure? 

As you can see from this table courtesy of Ofgem, the average property in the UK uses approximately 2,700kWh of electricity per annum:

The property in this case would be something like a 3-bedroom semi-detached, occupied by a family of 3-4 people.

Installing a 3.5kW solar panel system might seem excessive, but remember, solar panels don’t work at 100% efficiency and generate most of their power during daily sunlight hours. 

With 20% efficiency being the norm for solar panels, you’ll need a much bigger system than you think. Adding to this, the typical UK household uses the majority of their energy when solar panels aren’t generating much energy (if anything). 

Put simply, if you don’t have solar panels installed with a storage battery, the majority of the electricity that your system produces is going to go to waste. 

You can read more details on how many solar panels you need here. Or, jump over to our solar panel tool here; this will calculate exactly what size solar panel and storage battery you need. 

Solar Storage Battery Costs

Solar panel storage batteries aren’t cheap. Expect to pay somewhere in the region of £5,000 for your battery including labour costs to hook it up to your system. 

The bigger the solar panel storage battery you use, the more it’s going to cost. For example, switching your 5kWh storage battery for a 10kWh is likely to add on £4,000 to your cost; approximately £9,000 in total for a 10kWh storage battery.

With the cost of solar panel storage batteries being so high, it makes sense to check: 

• How much electricity you are likely to produce using your solar panel system
• Electricity consumption during non-sunlight hours of the day (the times when you’ll be using electricity from the storage battery)

This allows you to size up your battery to the closest kWh possible, meaning you’re not paying for an oversized battery. Buying oversized batteries isn’t cost effective!

As a side note, if you do end up with a battery that’s too big, you’ll be able to sell energy back to the grid via the Smart Export Scheme. 

To qualify, you’ll need to have your panel system and storage battery fitted by an MCS certified solar panel installer. 

What’s The Lifespan Of A Solar Battery?

A solar panel storage battery will last between 5-15 years. However, there are plenty of variables that affect exactly how long it’s going to last including: 

• How hard you use / work your battery, as its lifespan is likely to be limited to 5,000-10,000 cycles
• The brand and quality of your storage battery (lesser known brands tend to be cheaper, but come with a short warranty and wear out faster)

We can’t emphasise enough how important warranty is when it comes to solar panel batteries. 

With an average lifespan of 10-years and an average cost for a 3-bedroom semi-detached property (5kWh battery) of £5,000, you need as much warranty as possible. 

If you don’t get a battery with a long warranty, you could end up with an expensive bill for a replacement just a few years after installing your solar panels!

Government Grants For Solar Batteries

Government grants are available for solar panel systems and solar batteries as well as payments on offer for any excess electricity that you produce. 

We’ve dropped some details on the most popular government grants for storage batteries below: 

0% VAT

The UK government has introduced a 0% VAT rate on various green energy products, including solar panel storage batteries.

This means your solar battery will be subject to 0% VAT rather than the typical 20% VAT rate that most goods and services in the UK are subject to. The scheme will run until 31 March 2027.

As of April 1 2027, VAT will refer to a new (but still lower) rate of 5%. However, with the UK government pushing towards a net-zero target, expect this 0% VAT rate to be extended. 

Using our example of a £5,000 solar storage battery, including VAT, you’ll pay £4,166.67. Put simply, you’ll save £833.33 on the cost of a £5,000 storage battery for your solar panels!

If you’re using a MCS registered installer, you don’t need to do anything to claim via the 0% VAT scheme; they’ll do it for you!

Use our solar panel price calculator here to find out exactly how much you’ll pay. 

Smart Export Guarantee (SEG)

The Smart Export Guarantee is a government scheme that allows households to generate electricity and sell it back to the grid. By doing so, you’ll be able to make a small income from any excess electricity you produce. 

A typical household will save up to £330 per year with solar panels, not using the SEG scheme: 

Planning to use the SEG scheme? Your net savings (after selling excess electricity back to the grid) will jump dramatically; up to £600 per annum:

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One important side note here is that to be eligible, your solar panel and battery installation needs to be completed by a MCS certified installer. 

Read more about eligibility criteria on the government’s website here. 

All Dwellow’s installers are MCS certified. You can get quotes on solar panel and battery installation by jumping over to our solar panel page here. 

ECO4

ECO4 is a government grant designed to help people that are on low incomes and receiving a means tested benefit. Those receiving the following means tested benefits are likely to be eligible: 

• Jobseeker’s Allowance
• Housing Benefit
• Pension Credit
• Child Credit
• Working Tax Credit
• Income Support
• Tax Credits

According to the Independent, 17% of households that have solar panels were able to access the ECO4 government grant. 

If you qualify for ECO4 you could receive up to 100% funding, meaning there's a possibility you’ll get free solar panels and battery storage. 

Jump over to Ofgem’s guide to ECO4 eligibility here. 

Or, contact our solar panel experts here; they’ll cross-check all government grants and confirm which ones you’re eligible for. 

How Much Can You Save Using A Solar Battery?

If you have a solar panel system installed that’s producing less energy at peak times than what your household demands, a solar battery could be the answer. 

Typical UK electricity tariffs mean that at peak times, energy is more expensive; this tends to be in the evenings. Unfortunately, this is also when your solar panel system is likely to be producing very little (if any) electricity; you’ll be buying electricity from the grid. 

By combining a solar panel battery with an off-peak tariff (for any electricity you need to buy from the grid), you can ensure you’re buying electricity at the most cost-efficient times of the day. 

Using solar panels with a battery could lead to savings of £600-£900 per year. This assumes you have a correctly spec’d system and suitably sized battery. 

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Confused about what size system or battery you need? Take out the guesswork by using our solar panel tool here. 

Solar Battery Advantages & Disadvantages

Not sure if a solar battery coupled with solar panels is for you? Below, we’ll cover some of the most important advantages and disadvantages. 

Advantages

Self-Sufficiency

Solar panel systems using a storage battery enable you to be self-sufficient when it comes to electricity. 

Electricity is expensive, and over time, prices will continue to rise. Not only will you save money now, you’ll protect yourself from any future price hikes. 

A system that doesn’t use a storage battery is only going to be self-sufficient during the hours of the day where the sun is strongest. At night (typically when households use the most electricity), it’s likely your solar panel system won’t be able to keep up with demand, so you’ll be paying for electricity. 

Check what size solar panel system and storage battery you need as well as getting fixed prices on-screen using our solar panel tool here. 

Smart Export Guarantee 

The Smart Export Guarantee (SEG) allows households to sell electricity back to the grid. 

Generating more electricity than you can use? Sell it back to the grid and earn a small income in the process. 

For many solar panel owners, this is a way to offset the high upfront cost of solar panels and is a huge advantage.

Low Maintenance

Solar panel batteries don’t need maintenance.

Generally, solar panel systems are checked by a professional engineer once annually. Whilst the engineer is completing routine maintenance on your solar panel system, they can check your battery (within a couple of minutes) is fully functional.

Due to the little time involved with checking if a solar battery is working correctly, the ongoing costs are next to zero.

Disadvantages

Upfront Costs 

The upfront cost of adding on a solar panel battery to your installation is the biggest disadvantage, with the average battery costing £5,000 for a 3-bedroom house in the UK. 

However, if your system has been spec’d correctly by your engineer, this investment will pay for itself over time. You’ll be saving more on electricity (that otherwise, you’d have had to buy from your energy supplier) than what your solar battery cost.

Lifespan

Another disadvantage worth considering is the lifespan.

Solar panels tend to last around 25-years (more details here on our page covering solar panel payback periods), whereas a storage battery is likely to last around 10-years. 

Put simply, at some point during your solar panel’s lifespan, you will need to replace your storage battery, at a cost of approximately £5,000. 

Do I Need To Maintain My Solar Panel Battery?

Solar panel storage batteries don’t need maintenance. 

It’s advisable to get a qualified engineer to service your solar panel system once a year. When they’re doing the service, they’ll be able to assess the condition of the battery within a couple of minutes. 

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Solar Battery FAQ

Is Battery Storage For Solar Panels Worth It?

Using solar panel battery storage removes the need to buy electricity from the grid, as well as enabling you to earn a small income from selling excess electricity back to energy suppliers. 

The combination of energy savings plus this income, means solar batteries are definitely worth the upfront cost.

How Much Does a Solar Panel System With A Battery Cost?

A typical 3-bedroom property will need a 3.5kWp solar panel system and a 5kWh battery. 

Expect the total cost including installation to be in the region of £12,000. 

How much does a 10kW battery cost?

The bigger the storage battery, the higher the cost. Whilst a 5kWh battery might only cost £5,000, a 10kWh battery will cost anywhere from £7,500-£10,000.

What is the best battery to use for solar panels in the UK?

Lithium-ion batteries are the most cost effective and efficient type of battery for solar storage. 

What Size Solar Battery Do I Need?

A typical 3-bedroom property with average electricity demand in the UK will need a 5kWh solar storage battery.

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