What Size Solar Battery Do I Need in the UK? (December 2024)

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To make the most of your solar panel system, you will need a solar battery. However, finding the right size solar battery can be a crucial part of meeting your home’s energy needs along with matching your solar panels. If this seems complicated and you’re stuck wondering “What size battery do I need?”, we’re here to help.

The size of the solar battery you need will depend on how many people are in your household. Generally, you will need something between 10kWh and 20kWh for the average home.

If you’re already looking for new batteries or solar panels and are ready to see some prices, we can offer help there as well. Our network is one of the best ways to easily and quickly obtain the best prices in your area. Moreover, we streamline your search for the right installer and make sure you only get offers from reliable ones. This cuts out days of laborious research on your end.

With our service, you can obtain up to 4 free, non-binding quotes for solar panels or batteries in no time. All you need to do is click the button below and fill out a 30-second form to get started.

When talking about battery sizes, there is a crucial distinction between the dimensions (physical size of the battery) and size (its capacity). This is important to know going forward because these do not always positively correlate. While a large battery can be more powerful, this also depends on the materials it relies on and how efficiently the system is packed.

For example, when comparing a lead-acid battery and a lithium battery of the same size, the lithium battery most likely lasts longer. The latter is also more expensive but that is the price of higher performance. Similarly, different manufacturers have different systems and size may not be indicative of how they perform.

That’s why, when we talk about size, we refer to the various aspects related to how much energy it can store (max capacity, usable capacity, etc.) measured in kilowatt-hours (kWh). With that cleared, let’s get into solar battery sizes and how they relate to your household consumption.

The solar battery size you need will depend on how many people live in your home. The table below illustrates how many batteries to power a house in the UK in both lead and lithium categories.

A single-bedroom house with an annual consumption lower than 2,000 kWh would require a lithium battery of 10.5kWh minimum or a lead acid battery of roughly 20kWh. Every additional 2,000kWh means adding 10 extra kWh to lithium batteries and roughly 20kWh to lead batteries.

Of course, finding the right battery can be a bit more complicated since these are average consumption levels. Many houses can exceed or underperform for various reasons. This is why the best way to get an estimate of the best solar battery for your situation is to contact an installer.

That said, finding an installer you can trust can be difficult, often requiring days of laborious research and price comparisons. Luckily, our service can help you find prices with none of the hassle. All you have to do is click the button below and fill out a quick 30-second form and you’ll receive 4 free, non-binding quotes from reliable installers in your area.

The right battery should have enough capacity for your needs so generally going larger is safer. However, too much capacity may mean you’re paying for more space than you need so it can be needlessly expensive.

At the same time, you should consider what you need the battery for. Having an oversized battery might come in handy if you want to charge external appliances like an electric car. On the other hand, buying smaller batteries can mean you can scale up later and add more when you need extra power.

Aside from the size of the battery, you should also consider the depth of discharge, capacity in series, and number of cycles the battery allows. You can learn more about sizes and other specs from our rundown of the best solar batteries.

An off-grid solar battery needs to be sized depending on what you will be charging. For vehicles and boats, the calculation for lithium batteries is to either use 3 times the maximum hourly production or twice the daily usage of the vehicle (depending on which number is less).

When it comes to vehicles, the fact that they move means they won’t always be ideally placed for peak sunlight hours, which is why it’s good to be on the safe side by leaning towards higher capacity. The capacity for lead batteries should be doubled compared to that of lithium batteries.

For an off-grid cabin or small home, it’s best to have a battery and solar array that can handle at least 1.8 to 2 times the daily electricity consumption in the building. For example, if a cabin uses 4kWh of electricity daily, you’ll want at least a 3kW array, but this depends on whether that array can generate 7 to 8kWh daily during winter (since winter is when sunlight is at its lowest).

If you’re considering investing in a solar battery for your off-grid property, then it’s worth taking a look at some of the best options on the market today. These include:

It’s important to note that off-grid systems require solar panels to be matched to both the battery and the needs of the home or vehicle. To determine what size battery for your solar panels would be most appropriate, you’ll need to understand your energy production. You can learn more about different sizes of solar panel systems from the various pages below:

Most solar batteries come with the ability to connect them in series. This can depend on the model and the manufacturer but most of them have this option. However, how many you can connect in a series can differ from battery to battery.

Additionally, “How much battery storage do I need?” is not the only question you should be asking as other factors also play a role. There are some things worth considering when looking for a solar battery you might want to connect in series:

With all the advice listed above, keep one thing in mind: there’s only so much we can help you without knowing the specifics of your system, your needs, and your home. That’s why the best way to find the ideal solar panel battery size is to ask an installer. Not only can they offer you their services, but they can also help you answer this important question: "Are solar batteries worth it?"

Finding an installer you can trust can be a daunting task that takes days of research and price comparisons when searching on your own. Luckily, you don’t have to waste precious time because we can instantly provide you with the best prices in your area through our service. Our network of thoroughly vetted installers can ensure you’re receiving the best solar battery price and installation service.

All you have to do is fill out a 30-second form with some basic information and we’ll handle the rest. In no time, you can receive up to 4 free, non-binding quotes from installers in your area. Click the button below to get started.