Solar Panel battery storage System UK Costs Guide

As the name suggests, solar battery storage, also referred to as an energy storage system allows you to store electricity generated by your solar panels during the sunlight hours.

This makes the electricity readily available for use in the evenings or on dull days, allowing you to become self-reliant and escape the ever growing expense of the grid.

But how much do solar battery systems cost? And are they always worth the investment?

In this guide, we’ll answer the most frequently asked questions, as well as average costs you can expect to pay for a new solar battery system.

How Much Do Solar Batteries Cost?

The cost of a solar battery system is dependent on many factors that include the brand of the battery, the batteries chemical composition, storage capacity and it’s life cycle.

On average, a complete solar storage system can cost between £2,000 to £7,000 depending on the factors mentioned above.

Like any new technology, solar batteries or home energy batteries are considered expensive and their price will likely come down as they become more commonplace.

Solar Battery Materials

There are two major types of battery material being used in solar batteries.

  • Lithium-ion batteries.
  • Lead-acid batteries.

Note: in general, lithium-ion batteries are considered the gold standard for domestic use and the most cost effective.

The lifespan, efficiency and cost of the solar batteries largely depend on the materials being used in them.

For instance, lithium-ion batteries can discharge 70% – 90% of the total storage.

Typically, a higher discharge rate and longer life span will result in higher prices. A lithium-ion battery can cost £3,500 to £6,000 depending on its usable capacity (kWh).

On the other hand, lead-acid batteries can only discharge 50% of the total amount of storage which means that they are available at comparatively cheaper prices.

A lead-acid battery can cost around £2,000 to £4500 depending on its usable capacity (kWh).

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Lifespan of Solar Batteries

The lifespan of a battery is a major factor to consider, since the more life cycles it can provide, the longer it can serve you and your home.

For instance, the average lifespan of solar panels is around 25 years, so it’s important to factor this into choosing a battery, as a battery with a limited lifespan may mean replacing your battery several times over the life of your panels, which can add up.

Battery Storage Capacity

There are two types of capacities that determine the effectiveness and cost of solar battery storage systems i.e., storage capacity and usable capacity.

The storage capacity is the total amount of electricity your battery can store while usable capacity means the amount it can use, which is determined by the depth of discharge (DoD).

Your solar battery slowly experiences a decrease in DoD with the number of cycles it goes through. For example, the use of 100 percent of the battery storage in a battery that has 85 percent DoD will shorten its lifespan.

The general rule is that the greater the storage capacity and usable capacity (measured in kilowatt hours), the more the solar battery will cost.

Solar Panel Batter Installation costs UK

The installation cost depends on the size and type of the battery.

It is typically more financially wise to set up your solar battery system while installing your solar panels.

Types of Solar battery storage UK

There are four main types of solar battery storage systems available in the market to choose from according to space, usage, output, and cost.

These are as follows:

  1. RV/Marine Solar batteries.
  2. Flooded type batteries.
  3. Gel batteries.
  4. Absorbed Glass matte (AGM) batteries.

RV/Marine Solar batteries

As the name suggests, these batteries are mainly used in RVs and boats. They have limited capacity and are used as a single source of electricity production.

Flooded type batteries

Flooded type batteries are lead-acid batteries and have a good life span as compared to marine solar batteries.

They emit gas when charged so it’s strongly advisable to install them outdoors or in an area with good ventilation.

Gel solar batteries

Gel batteries do not emit any kind of gas so are safer to use indoors. Since the batteries have a more constant temperature indoors, they perform better than the flooded type.

Absorbed Glass Matte (AGM) batteries

AGM has all the benefits of flooded type but of higher quality. They are risk-proof and have high performance.

They are more expensive than other types of batteries, but they maintain voltage better, self-discharge slower and last longer.

What grants available for solar batteries?

Even though a solar battery storage system may seem like a considerable expense, the good news is that there are some grant and funding opportunities available in the UK.

As of July 2022, these include the following solar battery grant schemes:

Home Energy Scotland

Home Energy Scotland Loan is an interest-free loan designed to help finance various energy efficiency initiatives and renewable systems like solar panels and solar batteries.

You can get a loan of up to £6,000 for a solar PV system, and £5,000 for a solar battery storage system.

The repayment period is between 5-10 years, depending on the installation. For specific eligibility criteria, you can visit the Home Energy Scotland website.

Other than that, there are no direct grant or loan offers in the UK but there are ways to save money with the schemes like Smart Export Guarantee (SEG) and VAT reduction.

Smart Export Guarantee

Smart Export Guarantee allows you to earn money for exporting stored electricity to the grid. Export tariffs depend on the suppliers, but a good tariff is between 4-6p/kWh.

Unfortunately, not many suppliers are allowing stored energy to be exported.

VAT Reduction Scheme

The other scheme which is VAT reduction can only be availed by people over the age of 60, having a low-income group or disability.

Those eligible for this offer only need to pay 5% VAT on products like solar batteries as opposed to the regular 20 % VAT.

Best Solar Battery in the UK

A solar battery that gives you more usable capacity, lifespan, DoD, and a longer warranty is going to offer you the best value.

Comparison table showing the costs of different solar batteries

Battery BrandUsable Capacity (kWh)CostBattery MaterialWarrantyLife CyclesDepth of Discharge (DoD)
Tesla Powerwall13.5 kWhFrom £5,700Lithium-ion10 yearsUnlimited*100%
SolaX 3.33.5 kWhFrom £4,010Lithium-ion10 years6,00095%
LG Chem RESU 6.56.5 kWhFrom £3,043Lithium-ion10 years6,00090%
Powervault 34 kWhFrom £4,470Lithium-polymer10 years>6,000100%
8 kWhFrom £7,020Lithium-polymer10 years>6,000100%

Tesla Powerwall undoubtedly takes a lead by offering 13.5 kWh usable capacity, 10-year warranty, unlimited life cycles and 100 per cent DoD.

The cost for Tesla is starting from £5,500 and in many cases Tesla also offer installation with their units, which is another major advantage.

The runner-up for the best solar battery according to the features it offers is Powervault3. It gives a usable capacity of 8 kWh, a 10-year warranty, 100 per cent DoD and more than 6000 life cycles.

However, the cost of Power vault 3 is starting from £7,020 which is considerably more than the Tesla model.

How long do solar panel batteries last?

The lifespan is an important factor contributing to the cost of solar battery storage.

A longer lifespan means fewer replacements while a shorter lifespan can add up to future costs.

For example, a lifespan for a solar panel is typically around 25 years which means a battery having a life span of 10 years will need to be replaced once during the lifespan of the solar system.

Meanwhile, a battery with a lifespan of 5 years must be replaced multiple times which adds to the overall cost of the battery during its lifespan.

The average lifespan for lead-acid batteries is 5 to 7.5 years while the average lifespan for lithium-ion batteries is around 11-15 years.

Is Solar Battery Storage worth it?

Since a solar battery storage system is a significant financial investment, you are probably wondering if it always makes financial sense to install one?

Typically, the best situation to install one is if you already have solar PV set up as a battery can easily be added to the existing system.

Equally, if you don’t yet have a solar PV array installed, it can make sense to install them both at the same time.

Why is this?

Essentially by installing a battery storage system with your solar PV array, you can make your solar panels much more efficient and save a considerable amount each and every month on your electricity bill.

Even if you don’t have solar panels installed on your roof, you can still take advantage of a battery storage system.

Many people use them to extract electricity from the grid during low peak times, helping you to reduce the amount you spend on electricity for your home.