A guide to solar battery storage
A solar battery is one of the best ways to get the most out of your solar panel system, by allowing you to store electricity generated from your solar panels so that you can use it when you need it, lowering your energy bills more than solar panels on their own.
With the number of homeowners installing solar panels going up, it makes sense that the number of people who own solar batteries is rising too. In a 2024 survey from Which.co.uk of more than 2,000 solar panel owners, 43% of them also had a battery, which is up 37% since 2019, where just 6% had batteries in addition to solar panels.
Solar Energy UK claims solar battery storage could contribute £1.6bn to the economy by 2035.
To help you determine if solar battery storage is right for your home, we’ve answered some of the most common questions we get asked about the topic.
How does solar battery storage work?
Solar batteries are a bit like a portable power bank that you can charge your mobile phone with when you’re out and about – only a solar battery is much bigger and less portable. You can charge it up using your solar panels and then use it to power your home, instead of using power from the grid.
When sunlight hits your solar panels, they turn this into direct current (DC) electricity, before converting it into alternating current (AC) electricity that powers your home. When your home fully powered, any excess solar energy will be rerouted to charge your battery.
If you’re out of your home during the day, you can use the stored power when you’re home in the evening – even when the sun has gone in.
Many of our customers generate and store power during the day and use it overnight – to charge an electric car, or run a washing machine or dishwasher. A solar battery can also work as a backup in the event of a power cut on the main grid.
What are the types of battery?
There are two main types of solar battery – lithium-ion and lead-acid batteries. As suggested from their names, lithium-ion batteries are made with the metal lithium and lead-acid batteries are made with lead.
Lithium-ion batteries are generally more common, and you’ll find them in many of the appliances in your home, including your phone, laptop and even printer.
While lead-acid are typically cheaper to buy and install, lithium-ion batteries offer better performance and value over a longer period of time, and work best with solar panels. More energy can be stored in lithium-ion batteries and they are said to be 95% efficient, meaning 95% of the energy stored in a lithium-ion battery is actually able to be used. Lead-acid battery efficiency is closer to 80%.
In addition to the actual battery, you need to think about how it will connect to a solar panel system. If you’re having both installed at the same time, it’s best to opt for a DC (direct current) battery, which connects directly to the panels and doesn’t require an additional converter.
If you already have solar panels, you’ll need an AC (alternating current) battery. This is much easier to retrofit into an existing system as it’s connected via the electricity metre but also requires an additional converter.
What does a solar battery cost? →
The cost of solar batteries can vary greatly depending on the capacity you need, the size of the battery, the brand, and whether it is included with a new solar panel system from us, added later, or installed to work with solar panels you already have.
In February 2024, the UK government added standalone solar batteries to its list of energy-saving materials that qualify for a 0% VAT rate until the end of March 2027, which reduces the upfront cost for you.
Our specialists would be able to recommend the best and most cost-effective solar battery for your home. Remember that installing a battery can also give you the potential to generate income by selling power to the grid, so that can make it a very attractive option in the long run.
Once installed, solar batteries require very little maintenance as long as you follow the manufacturer’s instructions when using them.
How much energy can they store? →
The amount of energy a battery can store depends on its capacity, which is measured in kilowatt-hours (kWh). Batteries are usually stackable, meaning you can add multiple batteries that can work together to increase your capacity for storage.
At EE Renewables, we offer a range of battery sizes and will choose the right capacity for you depending on your typical energy usage, how much backup power you want, and the amount of energy captured by your solar panels.
How much money can be saved? →
Solar panels can be a great long-term investment for any homeowner or small to medium business owner.
Without specific information relating to your household, it’s tricky to give an exact number when it comes to bill savings from solar storage. The Energy Savings Trust estimate homeowners could save up to £796 per year on energy bills by installing a battery storage system. Of course, that depends on the cost of your battery installation, the type of battery you choose (as well as your solar panel system), how much energy you use and how long the battery lasts for.
By combining solar panels, home battery storage and an air source heat pump, homeowners could create a system that saves almost all of their energy costs and their reliance on the grid, so they will not be vulnerable to power outages, power supply issues and energy price increases.
How long do solar batteries last? →
The exact life of a battery depends on a number of factors including its capacity, how often it is charged and discharged, environmental conditions and its average level of charge.
Typically, you could expect a battery to last around 10 years or 6,000 charge cycles. They have to perform repetitive, daily charging, and just like your phone’s battery, this eventually wears them out.
One charge cycle happens when 100% of a battery’s energy capacity is used, but not necessarily all at once. For example, if your battery is 50% charged, then fully charged to 100% at night, and the next day you use another 50%, that counts as one full charge cycle.
We’ll ensure your solar panel system and your battery storage are perfectly matched to make sure you get maximum efficiency of both of them working together.
Can a solar battery charge an electric car? →
Yes! Many customers first get interested in green home energy when they buy an electric car. If you are an EV driver, generating energy with solar panels and storing it in a solar battery during the day when you are using the car, and then charging the car from the battery overnight, makes for extremely cost-effective and environmentally friendly motoring. Whatever kind of electric vehicle you drive, our specialists can install EV chargers from leading brands and connect them to your solar panels and battery storage system to give you the ultimate environmentally-friendly home charging setup – just get in touch.
Are there any grants or schemes available? →
The government currently back an initiative called the Smart Export Guarantee (SEG), allowing homeowners to sell their excess electricity to energy companies. However, it’s better to save the electricity for latter and lower your energy bills.
This is because the current rate of grid electricity is 24.5p per kWh, and the best UK-wide SEG rate is 20p per kWh, so storing the energy rather than selling it makes more financial sense.
If we haven’t answered your question here or you would like to learn more about clean energy solutions for your home, get in touch with our specialists at sales@eerenewables.co.uk.