Batteries For Solar Panels: Solar Energy Storage

Solar batteries allow you to store excess electricity generated by your solar panels to use as and when you need it.

A solar battery costs around £1,500 to £6,000, depending on how much electricity it's able to store.

Solar batteries can be installed at the same time as solar panels, or can be retrofitted to solar panels which have already been installed.


What's in This Guide to Solar Batteries?

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How Does Solar Battery Storage Work?

A solar battery lets you store electricity generated by your solar panels for use at a later time so that it’s not wasted. If you already have solar panels (or are planning to install them), buying a solar battery can help you to maximize the amount of electricity you use from your solar panels.

93% of homeowners we surveyed think that solar batteries are a good investment*

*Based on a survey we conducted in January 2018 of 310 UK homeowners with a solar battery storage system.

But why is this important? Solar panels can only produce electricity when there is sunlight. This creates a problem when it’s dark or overcast and you need energy to power your home, meaning you have to buy it from the National Grid.

Solar batteries can provide you with a constant source of free electricity, so long as the storage unit is big enough for your energy usage. This means that you won’t need to buy as much electricity from the Grid, slashing your energy bills and moving you a step closer to self-sufficiency.

Remember: if your solar panels are registered for the Feed-in Tariff, you’ll receive money for the electricity you generate and export to the National Grid (the Export Tariff). Currently, this is estimated to be around 50% of what you generate. If you install a solar panel battery, your payments from the Export Tariff will still be based on this percentage regardless if you store some of your electricity. After smart meters have been installed in homes, however, the UK Government may start to base Export Tariff payments on actual meter readings. So if you’re storing some of the electricity you generate in a solar panel battery (rather than exporting it to the National Grid), the amount you can earn from the Export Tariff will decrease.


To find out more about how solar panels can make you money, read our guide on the Feed-in Tariff.


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Compare Solar Batteries

Despite being a relatively new product, the solar battery industry is growing rapidly, with a range of companies putting new solar storage units on the market every year.

The sizes of solar batteries can range from a microwave up to a small fridge - and the bigger they are, the more electricity they can store. Small batteries are fine to be mounted onto your wall, while large batteries are often safer when floor-standing. The storage capacity of solar batteries typically ranges from 1kWh up to 14kWh - the latter giving you enough power to boil your kettle up to 120 times; that’s a lot of tea!

Good to know: the stated storage capacity of a solar battery is often less than its actual storage capacity. This is because batteries will lose some capacity from charging and discharging, and this is more so over time.


Most households will only need 1 solar battery to store enough electricity to power their home. If you’re looking to maximise the amount of energy you can store, however, some companies produce ‘stackable’ systems. These are made up of more than 1 solar battery, enabling you to store large amounts of electricity to use when needed.

The table below compares the key features of some of the best-selling solar batteries* available in the UK, including their storage capacity, size and warranty period:

Battery Name

Size

Mounting

Storage Capacity

Product Warranty

Availability

E.On Storage
45cm x 43cm x 10cm
Wall-mounted
2.4kWh, 9.8kWh
10 years
From UK installers in selected counties
Moixa Battery
50cm x 30cm x 24cm
Wall-mounted
2kWh, 3kWh
10 years
Direct from Moixa
Powervault Lithium-ion G200
50cm x 58cm x 82cm
Floor-standing
2kWh, 4kWh, 6kWh
10 years
From UK installers
Samsung Energy Storage System
100cm x 27cm x 68cm
Floor-standing
3.6kWh
5 years
From UK installers
Solarcentury Solar Battery Storage (Ikea)
45cm x 40cm x 12cm
Wall-mounted
3.3kWh
10 years
Direct from Ikea
Tesla Powerwall
76cm x 115cm x 16cm
Floor-standing
14kWh
10 years
Direct from Tesla

*All these solar batteries are designed to work with the National Grid.


What Are Batteries for Solar Panels Made From?

Solar batteries can be made from lead acid or lithium ion. Lithium ion batteries are the most common, but lead acid batteries are often more affordable.

Lead acid: lead acid solar batteries have quite a short lifespan compared to lithium ion batteries, but they are the cheaper option. If you’re looking to maximise the amount of electricity you can store by installing several solar batteries, lead acid can be a good option.

Lithium ion: most solar batteries are made from lithium ion, including the Tesla Powerwall. Lithium ion batteries are smaller and lighter than lead acid types, and have a longer lifespan. Because of this, they are the more expensive option.


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Solar Battery Storage System Cost

The cost of solar battery storage systems typically range from just over £1,500 up to £6,000. From a survey that we conducted in January 2018 on 310 UK homeowners with a solar battery, 86% paid less than £4,000 for their solar energy storage. Obviously, the more electricity a solar battery can store, the more it’s likely to cost.

The table below shows you the typical price of some of the best-selling solar batteries available in the UK:

Battery Name

Typical Price

E.On Storage
£4,500+
Moixa Battery
£2,950+
Powervault Lithium-ion G200
£2,550 - £4,550
Samsung Energy Storage System
£5,600
Solarcentury Solar Battery Storage (Ikea)
£3,000 - £5,000+
Tesla Powerwall
£6,000


We recommend that you compare quotes from at least 3 solar battery installers to find the best price. Make sure you know exactly what is included in each quote, and ask an installer questions if you’re confused over a calculation.

Getting quotes needn’t be a chore, however. By filling in the short form at the top of this page, we can get you a personalised quote for a solar panel battery quickly and easily.

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Solar Battery Pros and Cons

Pros

Enable you to use more of the electricity your solar panels generate

Are low maintenance and reliable, with a product a warranty of at least 5 years

Allow you toreduce your spend on energy bills by up to 35%

Can be installed at the same times as solar panels, and into homes that already have solar panels

Have a large storage capacity of up to 14kWh


Cons

Can be quiteexpensive, costing up to £6,000

Big solar batteries require a large amount of free space in your home to be installed

Last between 5 and 15 years, so they'll need replacing during the lifetime of your solar panels


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Installing Your Solar Battery

Whether or not you already have solar panels will affect whether you can install a DC solar battery system or an AC solar battery system.


DC Solar Battery Systems

DC batteries are connected directly to your solar panels. This means you won’t need to install an additional inverter to convert the electrical DC power stored in your battery into AC electricity you can use to power your home. DC batteries tend to be installed at the same time as solar panels, but they can be retrofitted to existing solar panels (although the installation process is a more complex and will take longer to carry out).


AC Solar Battery Systems

AC batteries are not connected directly to your solar panels - instead, they are connected to your solar panels via the electricity meter. This means you will need an additional inverter installed to convert the DC electricity from your battery into useable AC electricity.. If you already have solar panels, you’ll probably be offered an AC battery storage system as they are much easier to retrofit.

You should always seek professional help when choosing and installing a solar battery storage system. Make sure your installer is signed up to the Renewable Energy Consumer Code (RECC) as this ensures that they’re signed up to a high standard of conduct, and covers you should you need to make a complaint or claim.

Good to know: when installing a solar battery, you’ll need to tell your local Distribution Network Operator (DNO), and you might also be required to inform your local council.


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