The complete guide to solar battery storage

If you’re looking at upgrading your home, making use of renewable energy sources and installing solar panels, you’ll probably have seen solar battery storage systems mentioned. 

Likewise, if you have an existing solar panel system and you want to maximise its efficiency, store excess energy and reduce your energy bills further, you may be considering investing in a solar storage battery. 

Either way, if you’re looking into solar battery storage solutions, you’re in the right place. 

Here, our solar panel experts explain everything you need to know about solar battery storage, from the benefits of having them installed to how much they cost, and whether solar batteries are right for your home.

What are solar batteries? 

A solar battery, which may sometimes be called a home battery or energy storage system, lets you store electricity generated by your solar panels. You can then use this stored energy at a later time. For example, a solar battery could save energy during the day to power your home at night. If you don’t have a solar battery, the excess energy is sent back to the National Grid so it doesn’t go to waste. 

Essentially, if you’re harnessing solar energy to power your home, a battery storage system will help you maximise all of the energy your solar panels generate. Pretty good idea, right? 

How are solar batteries installed? 

Installing solar batteries is quite straightforward, you just need to find a good place to store them.

Normally a solar battery will be fitted inside in a loft, cupboard or integrated garage. Basically, anywhere that’s out of the way but is accessible in case maintenance work is required. Once a suitable location has been found, it’s a case of connecting the battery to the inverter and fuse board, which only takes a few hours.  

If you currently have a solar PV system, you’ll already have a solar inverter (also known as a controller) fitted in your home - this converts solar energy (DC electricity) to alternating current (AC) electricity, which is what’s used on the electrical grid. 

Your solar battery should be fitted as close to the inverter as possible, to minimise voltage loss and maximise the power generated by your solar panels. 

Some solar batteries can be installed outdoors, but we recommend having them fitted inside, where they’re protected from the weather. 

How much do solar panel batteries cost? 

A solar battery can cost anywhere from £2,000 up to £8,000 depending on the storage capacity and type of battery you choose. Obviously, if you want to buy the best solar batteries, these will cost more than standard systems - check out our ultimate guide to solar panels to understand the different types available.

Are solar panel batteries cost-effective?

There are a couple of factors to consider before determining whether a solar panel battery is cost-effective - you first need to ascertain: 

• How much electricity your solar panels currently generate
• How excess electricity is sent back to the National Grid
• How much electricity you currently use 

If your solar PV panel system currently generates more electricity than your home uses, it may be a wise choice to invest in a battery system, so you can use this energy at a later date. 

Due to the costs associated with buying and installing solar panels and a battery, it can take years for you to save more money than the cost of procuring everything. 

Aside from just spending less on your energy bills, another huge benefit to having solar panel systems and batteries installed is that your carbon footprint will reduce too. While many people do look to the savings as the main benefit of solar power, the sustainable reward is great too.  

What are the different types of solar panel battery storage?

There are four main types of solar batteries: 

1. Lithium-ion batteries

The most common type of solar battery, lithium-ion batteries, charge quickly and have a higher density, so they can store more energy and require less maintenance. This makes them a common choice for solar batteries. 

2. Lead-acid batteries 

Having been around for over 100 years, a lot of solar technology was developed using lead-acid batteries, meaning they are a tried and tested solution.

The longevity and development of lead-acid batteries means they are very cheap and reliable. 

Lead-acid batteries come in two different types - sealed and flooded. Sealed lead-acid batteries are valve regulated and reduce the risk of potentially harmful gases being expelled. 

Flooded lead-acid batteries, on the other hand, need to be stored in temperature-controlled and well-ventilated areas, as they are prone to releasing hydrogen gas.

3. Nickel batteries

Nickel-cadmium batteries have, like lead-acid batteries, been around for over 100 years, meaning they have been refined to make them more efficient.

These batteries suffer from two serious problems, one is that cadmium is highly toxic and it’s even banned in some countries and the other is that the cadmium makes recycling these batteries virtually impossible. 

4. Flow batteries

These batteries take their name from how they operate. Basically, a water-based electrolyte will flow between two individual chambers. One of the best features of a flow battery is that 100% of the energy they store can be used, due to its impressive depth of discharge. 

The two types of battery installation systems 

In addition to these four types of batteries, there are two types of battery installation, that are outlined below. 

Before we get into that, you need to know that energy generated by solar panels and kept in solar batteries is in direct current (DC) form and the energy we use in our homes is in alternating current (AC) form. 

1. AC-coupled battery system

In an AC battery system, the electricity travels from the solar PV panels into the inverter, where it’s transferred into AC form; any energy that’s not used is converted back into DC form through a battery inverter and stored in the battery. 

Alternatively, you could purchase an AC/DC power unit, which converts electricity through the same inverter. 

Simply put, with an AC battery system, this is a more complex process and installation may be more expensive than DC systems as a result. 

2. DC-coupled battery system

A DC battery system is connected directly to the solar panel system, as opposed to being connected through the inverter, so you’ll only need one inverter. One drawback of a DC system is that charging and discharging the battery is less efficient. 

DC systems are usually not recommended if you’re installing a battery into existing solar PV systems because AC battery systems are easier to retrofit.

The verdict: is solar panel battery storage right for your home?

If you currently have a solar panel system installed in your home and you’re generating excess power, a battery will help you maximise the use of the energy generated. 

Likewise, if you think solar installation might be for you, having a solar battery installed can help you live more sustainably, reducing your carbon footprint as well as your energy bills. 

Buying a solar battery can be expensive, so before you commit to one, you should speak to an expert to determine whether it will be worth the money.

For additional tips and support on buying and maintaining solar panels, bask in the rays of our solar guides. We also have a series of solar FAQs, for anything else.

The pros and cons of having solar batteries installed

For those of you looking for a concise, digestible overview of whether a solar battery is worth the money, we’ve collated all of the pros and cons below: 

Pros	Cons
Can help you to save money in the long-term	Significant upfront investment
Allows you to use all of the electricity your solar panels generate	May not be suitable if your solar panels don’t generate much electricity
Can be used as a backup power supply if there’s a power outage
Will further reduce your carbon footprint

Want to get started living more sustainably? Explore our solar solutions here.