Do I Need a Solar Battery for my Home?

Home solar batteries are becoming increasingly popular for several reasons—here's why they're worth considering. Solar storage isn't just a novelty anymore; it’s a practical option for many homeowners, not just those looking to go fully off-grid. Technological advancements and government incentives have made this a feasible solution for sustainable energy at home.

This article will guide you through everything you need to know about solar batteries, helping you decide if they’re right for your property. After reading, consult an experienced solar installer for personalized advice.

Below, we answer some of the most frequently asked questions about solar batteries:

• What exactly are solar batteries?
• How do solar batteries function?
• What types of solar batteries are available?
• What is the cost of solar batteries?
• How much energy can solar batteries store?
• How long do solar batteries last?
• What factors influence the lifespan of a solar battery?
• What government incentives are available for solar batteries?
• How to select the right solar battery
• Do I really need a solar battery at home?

The UK has set ambitious goals to reduce emissions by 78% by 2035 compared to 1990 levels. Every individual can play a part in achieving these goals, and adopting solar power and storage is one way to contribute. Beyond 2035, the UK aims for net-zero emissions by 2050, making this the perfect time to embrace renewable energy solutions in your home.

While we can't tell you whether a solar battery is necessary for your home, we aim to provide you with all the facts so you can make an informed decision. Let’s start with the basics—what are solar batteries and how do they work?

What Are Solar Batteries?

Think of solar batteries as oversized versions of the AA batteries you might use in your TV remote, except instead of powering a single device, they store energy generated by your solar panel system. This energy, derived from the sun’s photovoltaic (PV) power, can be used when needed—day or night.

With a solar battery, you’ll never have to worry about running out of power. You can even go off-grid entirely if you wish, relying solely on the energy produced and stored in your solar setup. Additionally, energy stored in a solar battery can be sold back to the grid, with government programs offering incentives and tariffs for doing so.

Unlike traditional batteries, solar batteries don’t “die” after a certain number of uses—they recharge continuously whenever your solar system generates power, which is typically during daylight hours.

Solar batteries are essentially large-scale storage solutions for excess PV energy generated by your solar panels.

How Do Solar Batteries Work?

In the past, any excess energy produced by solar panels would be sent directly to the grid. Now, with solar batteries, that excess energy can be stored and used later. Each solar battery has a capacity that indicates how much power it can hold. Some batteries are even stackable, allowing multiple units to be connected for greater storage capacity.

The depth of discharge (DoD) refers to how much of a battery’s total capacity can be used before it needs recharging. For instance, a battery with a 100% DoD allows you to use the full capacity (e.g., 3.0kWh), whereas a battery with a 96% DoD limits you to 2.8kWh of the 3.0kWh before needing a recharge.

Different battery types are better suited for different applications. Keep reading for more details.

What Types of Solar Batteries Are Available?

The two most commonly used solar battery types today are lithium-ion and lead-acid. Despite being relatively new to the market, lithium-ion batteries dominate due to their longer lifespan and higher usable capacity compared to other types.

Lead-acid batteries, on the other hand, have been around since the 1800s and remain popular because of their durability and reliability. Here’s a closer look at the benefits of each type:

Lithium-Ion

• Long lifespan (thanks to higher discharge depth*)
• Extended warranties (often 10+ years)

*Discharge depth refers to the percentage of energy a battery can use before requiring a recharge.

Lithium-ion batteries are ideal for powering homes because they offer substantial storage capacity in a compact space. They’re particularly effective for households with high energy demands.

Lead-Acid

• Historically the most affordable storage option
• Highly reliable
• Easier to dispose of or recycle due to longstanding technology

Lead-acid batteries are excellent for off-grid solar setups and serve as reliable backup batteries during emergencies.

How Much Do Solar Batteries Cost?

The cost of solar batteries varies depending on your needs. The size of your solar system determines how much storage you’ll require, which in turn affects the capacity and price of the battery. Different brands and models naturally vary in price.

Your primary concerns will likely be the durability and capacity of the battery. Balancing these with your budget is the best approach.

How Much Energy Can Solar Batteries Store?

The amount of energy a solar battery can store differs from how much storage you actually need. Consider both the size of your solar system and your daily energy consumption habits.

For example, a 5kW solar power system generates approximately 20kWh of energy on a sunny day, totaling around 4,500 kWh annually. Without a battery, around 13kWh is typically fed back into the grid each day.

For systems of this size, a battery with a capacity between 10kWh and 13kWh is recommended to store excess energy for use during the night or in emergencies. Ultimately, the size of the battery you choose depends on your goals.

How Long Do Solar Batteries Last?

Current solar batteries are designed to last up to 15 years, though advancements in technology are expected to extend their average lifespan significantly.

While 15 years is impressive, it’s worth noting that the battery will likely need replacing before the solar panels themselves. Major manufacturers usually offer warranties covering their products, typically lasting 10 years or 10,000 charge cycles, whichever comes first.

What Factors Affect the Lifespan of a Solar Battery?

Several factors influence the longevity of a solar battery, including usage frequency, battery type, and storage conditions. Here’s a deeper dive:

Frequency of Use

Think of a smartphone battery—regular charging gradually reduces the effectiveness of each charge cycle. Over time, this degradation becomes noticeable, though often subtly. The same principle applies to solar batteries.

If a solar battery is used nightly to power your home, it will wear out faster than one used only for emergencies. Similarly, using the battery repeatedly to go off-grid will accelerate its aging process.

Type of Battery Installed

Solar batteries come in three main types: lead-acid, lithium-ion, and saltwater. Among these, lithium-ion batteries stand out for their longevity and storage capacity.

Refer to the previous sections for a detailed comparison of the three battery types.

Storage Environment

A solar battery should be stored in a dry, temperature-controlled environment—not too hot or too cold. Proper storage ensures a longer lifespan. Manufacturers will provide specific guidelines based on the battery type.

General temperature recommendations include:

• Lead-acid: 4°C to 8°C
• Lithium-ion: -17°C to as high as 60°C

Extreme temperatures negatively impact batteries, so proper storage is crucial. Direct sunlight should be avoided. Low-maintenance batteries can be kept indoors, while others require more care and should be housed in a ventilated box in a shed, garage, or similar location.

In all cases, a solar battery should be stored in an area with sufficient thermal mass to absorb heat and prevent adverse effects on its condition and performance. Common materials used to enhance thermal mass include concrete, filled concrete, and stone.

Still have questions about solar batteries or panels? Reach out to a dedicated solar battery expert.

Government Incentives for Solar Batteries

Before investing in solar panels and a storage solution, it’s important to familiarize yourself with the following government incentives, which can lower the cost of solar battery installations and provide long-term savings.

VAT Reduction

Certain renewable technologies, including solar panels and storage, qualify for a reduced VAT rate of 5%. Suppliers will apply this reduced rate to the installation and any additional work required.

• Central heating and hot water system controls
• Draught stripping
• Insulation for walls, floors, ceilings, and lofts
• Solar panels and storage
• Ground-source heat pumps
• Air-source heat pumps
• Micro combined heat and power units
• Wood-fuelled boilers

Eligibility Requirements

To qualify for the reduced VAT rate, you must be over 60 years old or receiving one or more of the following UK government benefits:

• Child Tax Credit (excluding the family element)
• Council Tax Benefit
• Disability Living Allowance
• Personal Independence Payment
• Disablement pensions
• Housing Benefit
• Jobseeker’s Allowance (income-based)
• Income Support
• War Disablement Pension
• Working Tax Credit

How to Choose the Right Solar Battery

When selecting a solar battery for your home, consider the following key factors that impact the system's capacity and long-term performance:

1. Battery life and warranty
2. Power capacity
3. Depth of discharge (DoD)

Another consideration is the purpose of the battery. For going off-grid entirely, lead-acid batteries are recommended due to their durability. Lithium-ion batteries, on the other hand, are ideal for homes because of their long lifespan, large capacity, and compact size.

Do I Need a Solar Battery at Home?

Solar batteries for homes are becoming increasingly popular. If you have any questions about solar panels or solar batteries, our friendly team is ready to assist you.

For more insights into solar panels, visit our blog for articles covering various topics to help you choose the right panels and understand essential aspects like maintenance.