Your guide to solar panel batteries in the UK

We all know that solar panels are a great way to embrace renewable energy and save money — but there’s a key element of solar power that many of us are less aware of. Solar panel batteries make harnessing the sun’s rays even more productive. They capture and store the abundant energy the sun provides for use at your convenience. But how?

During the day, your solar panels will be diligently absorbing sunlight and converting it into electrical energy. (Remember, solar panels can still work on cloudy days — they absorb ambient light, not just direct sunlight.)

Often, the energy your photovoltaic (PV) panels generate exceeds your household’s immediate needs. This excess energy is where solar panel batteries excel. They store this surplus, making it available for later use, especially during periods when sunlight is scarce, such as at night or in the winter when the sun rises later and sets earlier. 

The technical workings of these batteries revolve around converting and storing energy. Solar panels capture solar energy and convert it into direct current (DC) electricity. However, most homes and appliances operate on alternating current (AC). An inverter transforms DC into AC so you can use the stored energy at home.

For an in-depth explanation of the storage process, why not discover how solar batteries work?

There are two main types of solar batteries in the UK.

Lithium-ion batteries

Lithium-ion batteries stand at the forefront of solar battery technology. They store energy through lithium ions moving between electrodes — a highly efficient process. This efficiency means they can store more energy in a smaller space, making them ideal for homes with limited space. 

Though they have a higher upfront cost than other battery types, their durability and efficiency can lead to cost savings over time.

• Price: Lithium-ion solar batteries generally cost from £3,400 to £6,000.

  
  

• Lifespan and maintenance: Their advanced technology of lithium-ion solar batteries ensures a longer lifespan, often up to 10-15 years, and they require minimal maintenance.

  
  

Lead-acid batteries

Lead-acid batteries, the veterans of solar storage, operate by a chemical reaction between lead plates and sulphuric acid. This traditional technology is more straightforward and thus less expensive to manufacture. They are larger and heavier than lithium-ion variations, which means they require more space.

Lead-acid batteries are a cost-effective solution for those with larger installation spaces and a tighter budget.

• Price: The average cost of a lead-acid solar panel battery in the UK ranges from around £1,500 to £3,000. 

  
  

• Lifespan and maintenance: With an average lifespan of five to seven years, they don't last as long as lithium-ion. They also require more maintenance and TLC to keep them running optimally.

  
  

Solar panel banks

While not a different type of solar battery, solar panel battery banks refer to a group of batteries linked together within a solar power system. This setup is designed to store excess energy generated by your solar panels. 

The beauty of a solar panel bank is its capacity to hold large amounts of energy, ensuring a reliable power supply even when the sun isn’t shining. It's especially useful for off-grid systems or in areas with unreliable power sources. By having multiple batteries connected, you can store more energy, providing greater energy security and efficiency for your home or business.

Wondering what happens when your solar panels produce surplus energy? It all depends on your setup. 

Sending Excess Power Back into the Grid

Grid-connected solar systems direct excess energy to the grid. This means that no energy is wasted and you even get paid for your solar energy. This can come as payments or as credits to offset any future payment to the electrical grid.

Energy Load Dumps

Some systems are built with a backup ‘store’, which receives the excess energy once your battery has reached its capacity. This can be another battery or other device with the capacity to store energy. Ultimately, this means no energy is wasted. 

Redirecting Power Back into the Panels

The excess energy can be redirected back into the solar panels. The idea here is to manage the power flow to prevent it from damaging the system. This is sometimes known as ‘curtailment’ or ‘clipping.’ This energy is effectively lost as it is no longer stored to power your home.

If you’re thinking about solar panel installation, you might be wondering if you can have solar panels without a battery. You absolutely can install solar panels without a battery — they are not a compulsory component. 

However, we recommend exploring the benefits of solar panel batteries before writing them off as an extra cost.

At SpotDif, we believe getting a balanced view of home improvements is important before investing. As such, we recommend noting the potential drawbacks of solar batteries. In our experience, these include:

• A higher upfront cost: Installing a battery for your solar panels is a significant investment, adding a few thousand pounds to your setup. This can be a barrier for some households hoping to integrate battery storage.

  
  

• Space requirements: You also need a dedicated area for your battery, which can take up anywhere from 1.2 square metres (12 square feet), including requisite space around the battery unit.

  
  

• Lifespan: While solar panels can last for over 20 years, solar batteries tend to have a lifespan of between five and 15 years, meaning you will likely need to replace your battery long before updating your solar panels. Replacement will add to your long-term battery costs.

It’s time to look at another vital factor in choosing batteries for your solar panels — the cost.

Prices vary, starting from as little as £1,000 but the average cost for a solar battery tends to be around £5,000 to install on its own or £2,000 to £3,000 if you install it at the same time as your solar panels.

So, what causes this price variation?

1. The battery size and type

As we mentioned, lithium-ion batteries tend to be more expensive than lead-acid ones, with the former costing from £3,400 to £6,000 and the latter coming in at around £1,500 to £3,000. 

Size matters too. Your solar battery’s storage capacity will be measured in kilowatt-hours (kWh), and the higher the capacity, the more energy it can store. Generally, a larger capacity also comes with a higher price tag. On average, you should expect to pay around £900 per kWh of storage capacity.

2. Installing the solar battery after your PV panel installation

The average cost of a 5 kWh solar battery is roughly £5,000, including the price of installation and an inverter. However, if you add that 5 kWh battery onto a solar panel installation, its price generally falls to between £2,000 and £3,000, as you’re already paying for the labour and an inverter.

Likewise, a 10 kWh battery might cost £7,000 by itself, on average, but if it’s part of a solar panel and battery kit, its price typically drops to £4,000 to £5,000. 

In many cases, you’re better off making all your planned changes to your home at once — otherwise, you’ll end up paying more than you need to.

3. Brand and quality

As with many products and services, the price of your battery will also depend on the manufacturer. A well-known solar company with better warranties and support services may command higher prices. 

We suggest exploring quotes from different solar panel and battery companies to get a good idea of your options. And don’t forget, we’re always on hand with our comparison tool to help. We’ll do all the research for you, bringing you a list of offers from trusted suppliers.

4. Maintenance and warranty

Often, solar panel batteries that have less maintenance — and therefore come with more comprehensive warranties — cost more. The higher price comes from the reduced risk for you, the customer.

At SpotDif, we're here to help you make sense of all the costs involved with solar panel batteries and battery installation. We provide comprehensive comparisons of different solar panel batteries, taking into account their type, capacity, and overall value for money. Our goal is to find you a solar battery solution that aligns with your energy needs and financial plans. 

If you’re keen to harness the power of the sun, we recommend using our helpful starting your search for a solar battery provider by using our handy comparison tool.