Solar Energy Storage: Navigating Solar Battery Storage for Homeowners

Solar panels are an excellent way to generate your own renewable electricity and reduce your reliance on the grid. But without somewhere to store that energy, you’re only using power as it’s produced. Solar battery storage changes that, allowing homeowners to use their solar energy day or night, and even during power cuts. If you’re considering storage for your home, this guide walks you through what it is, how it works, the types available, and how to choose the right option for your needs.

What is solar battery storage, and how does it work?

Solar battery storage is a system that captures excess electricity produced by your solar panels and stores it for later use. Without a battery, surplus energy is typically exported to the grid, often for a small feed-in tariff payment. With a battery, you can keep that energy and use it when the sun isn’t shining, reducing the amount of electricity you need to buy from your supplier.

The process works like this:

1. Daytime generation – Your solar PV system converts sunlight into electricity.

2. Home usage first – The system directs this electricity to your appliances and devices.

3. Battery charging – Any unused power is sent to your battery for storage.

4. Evening or night use – Once the sun sets or generation drops, your home draws from the battery before using the grid.

Modern systems often include smart controls, allowing you to schedule charging and discharging for maximum efficiency and cost savings. Some even integrate with time-of-use tariffs, charging from the grid at cheaper rates and using stored power during peak prices.

Benefits of adding storage to a solar PV system

So, what are the benefits of a solar battery storage system? Adding a battery to your solar installation offers more than just energy independence. Homeowners typically enjoy:

• Greater self-consumption – Store excess solar energy to use when you need it most.

• Lower energy bills – Reduce your reliance on grid electricity, especially during peak times.

• Protection against power cuts – Certain battery systems provide backup power to keep lights, fridges, and essential devices running.

• Optimisation with smart tariffs – Take advantage of cheaper overnight rates to charge your battery and save more.

• Reduced carbon footprint – Maximise your use of renewable energy, cutting the need for fossil fuel-generated power.

For many, the psychological benefit of knowing your home is less dependent on fluctuating energy prices is just as important as the financial savings.

Key battery types: lithium-ion vs lead-acid

When it comes to choosing a solar battery, two main types dominate the domestic market: lithium-ion and lead-acid. Each has its strengths and weaknesses, so it’s worth understanding the differences before making a decision.

Lithium-ion batteries

• Efficiency – High round-trip efficiency (around 90–95%), meaning you lose very little energy during charging and discharging.

• Lifespan – Typically lasts 10–15 years with thousands of charge cycles.

• Maintenance – Low maintenance compared to other types.

• Size and weight – Compact and lightweight for the amount of energy stored.

• Cost – More expensive upfront, but the longer lifespan often makes them more cost-effective over time.

Lead-acid batteries

• Efficiency – Lower round-trip efficiency (around 70–80%).

• Lifespan – Usually 3–5 years for deep-cycle lead-acid, with fewer charge cycles.

• Maintenance – Some types require regular maintenance, such as topping up water levels.

• Size and weight – Bulkier and heavier for the same capacity.

• Cost – Lower initial cost, shorter lifespan and reduced performance may lead to higher long-term costs.

In most modern home installations, lithium-ion batteries are the preferred choice due to their performance, longevity, and ability to integrate with smart home systems. Lead-acid batteries tend to be used in off-grid or budget-constrained projects.

Choosing the right size and capacity for your home

The size and capacity of your solar battery are critical to getting the best results. A battery that’s too small will fill quickly, leaving surplus solar energy unused, while one that’s too large may be underutilised, meaning you’ve paid for capacity you don’t need.

Here are some factors to consider:

1. Your daily electricity usage – Check your electricity bills to see how much energy you consume each day.

2. Solar panel output – The capacity of your solar PV system determines how much spare energy you’ll have to store.

3. When you use electricity – If your peak usage is in the evening, a battery can store daytime generation for that period.

4. Future plans – Consider if you may add an electric vehicle, heat pump, or other high-demand appliances in future.

As a rough guide, many UK homes install batteries between 4kWh and 10kWh. A smaller home with modest energy needs might opt for 4–5kWh, while a larger property or one with high evening use could benefit from 8–10kWh or more.

Costs, warranties, and return on investment

The cost of a solar battery in the UK typically ranges from £3,000 to £9,000 installed, with larger lithium-ion systems at the higher end. Beyond the upfront price, it’s important to consider warranty length, with many lithium-ion models offering 8–12 years of cover and guaranteeing a set percentage of original capacity after thousands of charge cycles. 

Potential savings come from reducing grid electricity purchases and earning through schemes like the Smart Export Guarantee (SEG), where homeowners can sell energy back to the grid. Payback periods vary depending on energy usage, system size, and tariff type, but for many homes, solar batteries return their cost in 8–12 years. For some, the decision is as much about securing energy independence and stable bills as it is about pure financial return.

Can you add a battery to an existing solar system?

Yes, in most cases, you can retrofit a battery to an existing solar PV installation. For this, there are two main approaches:

1. AC-coupled systems – The battery connects to your home’s AC wiring, independent of the solar inverter. This is often easier to retrofit, as it works alongside your current setup.

2. DC-coupled systems – The battery connects directly to the solar panels via a hybrid inverter. This can be more efficient but may require replacing your inverter if it’s not compatible.

When retrofitting, your installer will assess your existing solar equipment, electrical wiring, and available space. It’s also worth checking if your current feed-in tariff or SEG payments will be affected by adding storage – in some cases, you may need to notify your energy supplier.

Final thoughts: Is solar energy storage the right step for your household?

Solar battery storage isn’t for everyone, but it can be a game-changer for households looking to maximise their use of solar energy, cut bills, and reduce reliance on the grid.

It’s worth asking yourself:

• Do you use most of your electricity in the evening or at night?

• Are you on a time-of-use tariff where energy is more expensive during certain hours?

• Do you value backup power in case of outages?

• Are you planning to electrify more of your home, such as adding an EV or heat pump?

If any of these are relevant to you, a solar battery storage system could be a strong investment.

While the upfront costs can be significant, the combination of lower bills, greater independence, and environmental benefits makes solar energy storage an increasingly attractive option for UK homeowners. With the right battery size, type, and warranty, your system can serve you well for over a decade – helping you take control of your energy future. Compare solar today to find the best deals from trusted, vetted installers.