M&E Contrax Resources

Solar Battery Storage for Homes

Resource Highlights:

A home solar battery stores surplus electricity generated by your panels during the day so you can use it in the evening instead of buying it from the grid.

The two main system types are DC-coupled (integrated with a hybrid inverter) and AC-coupled (a battery added to an existing solar installation). Each suits different situations.

Battery capacity is measured in kilowatt-hours (kWh). Most homes with a standard 3.5 to 5kWp solar system get the best balance from a 5 to 10kWh battery.

Adding a battery typically increases self-consumption from around 30 to 40% without storage up to 70 to 80% with it.

Backup power during a grid outage is not automatic. Most standard battery systems are not configured for power cut protection unless specifically designed and wired for it. If resilience during outages is a priority, it needs to be discussed at the design stage.

How solar battery storage works, what it costs, and whether you need one

Most households generate more solar electricity than they use during the middle of the day, and less than they need in the morning and evening. Without a battery, that surplus goes to the grid at the export rate (typically 4 – 15p per unit). With a battery, you store it and use it yourself at whatever your retail rate is (typically 24 – 28p per unit). Over time, that difference adds up.

But battery storage is not right for every home, and it is not always the most cost-effective first investment. This guide explains how home solar battery storage works, which systems are worth considering, what “solar panels without a battery” actually means for your bills, and how to decide whether a battery is the right next step for your home.

We install a range of leading battery products including Tesla Powerwall, Fox Energy Storage, and more, and all electrical installation work is carried out by our in-house NICEIC-accredited engineers.

How does home solar battery storage work?

A solar battery connects to your solar PV system and stores electricity generated during the day that you do not use immediately. Instead of that electricity going back to the grid, it sits in the battery ready for you to use when generation drops, in the evenings, on cloudy days, or overnight.

The process looks like this:

Your solar panels generate electricity throughout the day

Your home uses what it needs in real time

Any surplus charges the battery rather than being exported to the grid

When the sun goes down or generation drops below your household demand, the battery discharges to power your home

Once the battery is depleted, you draw from the grid as normal

Most home battery systems are lithium-ion chemistry, similar to the battery in an electric vehicle. They have a usable capacity of between 5kWh and 16kWh, a lifespan of ten years or more, and no regular maintenance requirements.

Do you need solar panels to get a home battery?

No, but it usually makes more sense to have both. A battery without solar panels can still be useful if you are on a time-of-use electricity tariff (charging the battery overnight on cheap-rate electricity and using it during peak hours), but the payback period is longer without the free solar generation to fill it.

If you have solar panels and are considering adding a battery, it is worth doing a generation and consumption analysis first. Our team does this as part of the free survey, we look at your existing generation data and usage patterns to give you an accurate picture of what a battery would save you.

Solar panels without battery storage: is that still worth it?

Yes, and for many households it remains the sensible starting point. Solar panels without a battery still:

Cut your electricity bills by offsetting daytime grid consumption with free solar generation

Earn you Smart Export Guarantee income for any electricity you export

Qualify for zero VAT until 31 March 2027

Reduce your carbon footprint from day one

The typical payback period for solar panels without a battery is eight to twelve years for a domestic system. Adding a battery shortens the grid-import portion of your bills but adds to the upfront cost. For some households, particularly those with high evening consumption or an electric vehicle, battery storage makes the economics considerably better. For others, starting with panels and adding a battery later is the right call.

Battery technology can be retrofitted to most MCS-accredited solar installations, so you are not locked into a decision at the point of installation.

Adding a battery to existing solar panels

Which solar batteries are worth considering?

The home battery market has matured considerably and there are now several strong options available in the UK. These are some of the systems we work with most frequently:

Sigenergy

Sigenergy is one of the most compelling systems to have entered the UK market in recent years. Their modular battery architecture lets you start with a smaller capacity and expand later without replacing the core system, which makes it a practical choice for homeowners who want to future-proof their installation. Sigenergy batteries integrate neatly with their own inverter range and are compatible with most third-party solar systems. Monitoring is handled through a clean app interface with real-time generation, consumption, and battery state data.

FoxESS

FoxESS is a well-established battery and inverter manufacturer with a strong UK footprint. Their hybrid inverter and battery combinations are popular with installers because of their reliability and competitive warranty terms. FoxESS systems are available in a range of capacities and work well in both new installations and retrofits onto existing solar systems. Their monitoring platform gives clear visibility of system performance and export data.

SolarEdge Home Battery

SolarEdge produce a tightly integrated home battery designed to work specifically with SolarEdge inverters. If you have or are planning a SolarEdge solar system, the SolarEdge Home Battery is a natural fit, the integration gives better monitoring, more granular control, and a single system warranty. Capacities start at 9.7kWh.

Other systems

There are a number of other home battery systems available in the UK market, including Tesla Powerwall, Sunsynk, and Alpha-ESS. We specify the battery that is the best fit for your existing or planned solar system, your energy usage profile, and your budget, we do not push a single brand.

A note on battery brand recommendations
Battery technology and market availability change. This section reflects the position as of October 2026. When reviewing this page in future, update the brand notes and confirm current availability of all listed systems.

How long does a home solar battery last?

Most lithium-ion home batteries are warranted for ten years and carry a rated cycle life that typically exceeds that warranty period. In practice, battery degradation is gradual, most systems retain 70–80% of their original capacity at year ten.

Manufacturers warrant capacity to a minimum threshold (typically 70% of original) over the warranty period. After the warranty period, batteries continue to operate but with reduced capacity.

Adding battery storage to existing solar panels

Devon receives above-average solar irradiance for the UK, which means solar generation is strong from March through to October and meaningful even in winter months. The key question is whether your household consumes enough electricity in the evening and overnight to make effective use of stored generation.

Households that benefit most from battery storage typically have:

High evening electricity consumption (cooking, heating, entertainment)

An electric vehicle charged at home overnight

Working patterns that mean nobody is home during peak generation hours

A time-of-use tariff (such as Octopus Go or Agile Octopus) that incentivises charging the battery at cheap overnight rates

Our team will model your specific situation during the free survey and give you an honest assessment of whether battery storage makes sense for you, and if so, what capacity would suit your household.

Adding battery storage to existing solar panels

If you already have solar panels, battery storage can usually be retrofitted. The process depends on your existing inverter, some inverters are battery-compatible and the integration is straightforward; others require an additional battery inverter or a system redesign.

We carry out a technical assessment of your existing system before quoting for a battery retrofit, to make sure the specification is right and you are not paying for unnecessary additional equipment.

FAQs about solar battery storage

A solar battery stores surplus electricity generated by your solar panels during the day. Instead of exporting that electricity to the grid at the low export rate, the battery holds it for you to use in the evening or overnight when your panels are not generating. When the battery is full, surplus electricity is exported as normal.

No, solar panels work without a battery and still reduce your bills through daytime self-consumption and Smart Export Guarantee income. Battery storage improves the economics further by reducing the electricity you buy from the grid in the evenings, but it adds to the upfront cost. Whether a battery is the right choice depends on your usage patterns and budget. Our free survey includes a battery assessment.

In most cases, yes. Battery storage can be retrofitted to existing solar systems, though compatibility depends on your current inverter. We carry out a technical check of your existing system before quoting for a retrofit to confirm the right approach.

Most home batteries carry a ten-year manufacturer’s warranty and are rated for more cycles than that warranty period implies. In practice, batteries degrade gradually, most retain 70–80% of their capacity at year ten and continue to function beyond that.

Yes, until 31 March 2027. Battery storage installed alongside or separately from solar panels qualifies for zero VAT under the Government’s energy-saving materials relief. After 31 March 2027, the rate returns to 5%.

The best battery depends on your existing solar system, your energy usage, and your priorities. We work with Sigenergy, FoxESS, SolarEdge, and other leading brands. Rather than recommending one system universally, we specify the battery that is the best fit for your individual setup, the free survey is the starting point for that conversation.

Book a free solar battery survey

Whether you are starting from scratch with solar panels and battery storage, or looking to add a battery to an existing system, our Devon team is the right starting point. We carry out free, no-obligation surveys across Devon and the South West, and we give you an honest recommendation, not just a quote.

Call 01364 654271 or use our online enquiry form.

Last reviewed: October 2026. Figures quoted are from this date and can be different.