Combining solar panels with battery storage can allow a home or business to make greater use of the electricity generated by its solar PV system. Instead of using all of the solar electricity as it is generated, a battery can store surplus energy and make it available later when solar generation is lower.

For property owners in Cornwall considering solar panels, adding battery storage is therefore an increasingly important part of the conversation. The right system can combine solar PV generation, battery storage, intelligent energy management and, where appropriate, an electric vehicle charger or other electrical loads into one integrated energy system.

Trusted Tradesman can help you find solar and battery installation specialists in Cornwall and compare installers offering different approaches to system design and installation.

What is solar and battery installation?

A solar and battery installation combines two technologies:

  • Solar photovoltaic (PV) panels generate electricity from daylight.
  • A solar battery stores surplus electricity for use later.
  • An inverter converts the electricity between the DC and AC forms required by the solar panels, battery and property.
  • An energy management system monitors generation, consumption, battery charging and discharging.
  • Smart monitoring allows the system’s performance to be viewed through an app or online portal.

A typical system is designed so that electricity generated by the panels can first meet the property’s immediate demand. Surplus generation can then be directed into the battery. Once the battery is charged, further surplus electricity may be exported to the grid, depending on the installation and the owner’s tariff arrangements.

When solar generation falls, stored electricity can be discharged to supply the property.

This can make a solar PV system considerably more flexible than panels alone.

Why combine solar panels and battery storage?

Solar panels generate electricity during daylight hours, while household electricity consumption does not necessarily follow the same pattern.

For example, a home might generate substantial electricity during the middle of the day when occupants are away at work. Demand may then increase during the evening, after solar generation has fallen.

A battery provides a way of moving some of that electricity from one part of the day to another.

Use more of your own solar electricity

Without battery storage, surplus solar generation may be exported to the electricity grid.

With a suitably sized battery, some of that surplus can instead be stored and used later.

This can increase the proportion of solar-generated electricity that is consumed at the property.

Store electricity for the evening

Solar generation normally falls as the day progresses. A battery can discharge during the evening when household demand may increase.

This is particularly relevant for households with significant evening electricity consumption.

Combine solar with an EV charger

Homes with electric vehicles may have another substantial electrical load.

A properly designed system can take account of solar generation, battery storage and EV charging when considering how electricity is generated and consumed.

The installer should explain how the proposed system will operate rather than simply adding components independently.

Potentially use smart tariffs

Some battery systems can be configured to charge from the grid as well as from solar generation.

Depending on the battery, electricity tariff and control system, this may allow the battery to charge when electricity is cheaper and discharge at more expensive periods.

Whether this makes financial sense depends on the specific tariff, system and household consumption pattern.

Solar and battery installation in Cornwall

Cornwall has a substantial solar industry, with installers operating across areas including Truro, Newquay, Falmouth, Penzance, Redruth, Camborne, St Austell, Bodmin, Liskeard, Helston and Bude.

There are already a number of established solar businesses operating in the county, ranging from specialist solar companies to renewable-energy and electrical contractors.

For example, current local search results include Naked Solar in Newquay, I Spy Solar Cornwall and Devon in Newquay, CCS Heating & Renewables Ltd in Redruth and Solar Installer – ESE Group – Truro in Truro.

The important consideration, however, is not simply finding a company that installs solar panels. A solar-and-battery project should be designed around the property’s electricity consumption, generation potential and future requirements.

What does a solar and battery system include?

A complete installation may contain several components.

Solar PV panels

The panels generate electricity from daylight. The number and specification required will depend on factors including available roof area, orientation, inclination, shading and expected electricity consumption.

A good installer should consider the whole system rather than simply maximising the number of panels that will fit on the roof.

Battery storage

The battery stores electrical energy for later use.

Battery capacity is normally expressed in kWh (kilowatt-hours). However, capacity is not the only specification that matters.

The installer should also consider:

  • usable battery capacity
  • maximum charge rate
  • maximum discharge rate
  • battery chemistry
  • expected cycle life
  • warranty
  • operating temperature
  • physical dimensions
  • installation location
  • compatibility with the inverter
  • monitoring and control
  • whether additional batteries can be added later.

A larger battery is not automatically a better battery.

Inverter

The inverter is a critical part of the system.

Solar panels produce DC electricity, whereas most household appliances use AC electricity. The inverter manages this conversion and, depending on the system architecture, can also control battery charging and discharging.

Some installations use a hybrid inverter capable of managing both solar PV and battery storage.

Monitoring system

Most modern systems provide some form of online or app-based monitoring.

This can allow the owner to see:

  • solar generation
  • household consumption
  • battery state of charge
  • electricity imported from the grid
  • electricity exported to the grid
  • historical energy performance.

Monitoring can be particularly useful for understanding whether the system is operating as expected.

How large should a solar battery be?

There is no single battery size that is appropriate for every Cornwall property.

A battery should be selected based on the relationship between solar generation and electricity consumption.

A household using relatively little electricity may gain little from installing a very large battery. Conversely, a property with high evening consumption may benefit from greater storage capacity.

An installer should ideally examine:

  1. annual electricity consumption;
  2. typical daily consumption;
  3. when electricity is being used;
  4. expected solar generation;
  5. existing and planned solar capacity;
  6. EV charging requirements;
  7. heat pumps or other significant electrical loads;
  8. whether the battery will also be charged from the grid;
  9. available tariffs;
  10. the property’s future electricity requirements.

This is one reason why obtaining a system design rather than simply asking for a battery price is important.

Adding a battery to existing solar panels

You do not necessarily need to install solar panels and a battery at the same time.

A battery can potentially be added to an existing solar PV installation.

However, compatibility needs to be checked carefully.

The installer may need to consider the existing:

  • solar panels
  • inverter
  • wiring
  • protection equipment
  • generation capacity
  • export arrangements
  • consumer unit
  • monitoring system.

In some circumstances, adding a battery may involve replacing or upgrading the existing inverter.

A specialist should assess the existing installation before recommending equipment.

Installing solar panels and a battery together

For a new installation, designing the solar PV system and battery as a single system can provide advantages.

The installer can consider the relationship between:

solar generation → household consumption → battery storage → grid import/export

from the outset.

This can also help avoid compatibility problems between equipment supplied by different manufacturers.

If you are installing a new solar PV system in Cornwall and expect to add a battery later, it is worth discussing that requirement with the installer before the initial system is designed.

AC-coupled and DC-coupled batteries

There are different ways of integrating battery storage with solar PV.

AC-coupled systems

An AC-coupled battery has its own inverter and is connected on the AC side of the electrical system.

This can be useful when adding battery storage to an existing solar installation because it may not require the existing solar inverter to be replaced.

DC-coupled systems

A DC-coupled system connects the battery more directly with the solar PV system, often through a hybrid inverter.

This can provide an efficient way of integrating new solar panels and battery storage.

The best configuration depends on the property and equipment. It is therefore better to compare complete system designs rather than assuming that one architecture is universally superior.

Solar battery installation for existing solar PV systems

If you already have solar panels in Cornwall but do not have a battery, you could ask an installer to assess whether battery storage is suitable.

Useful information to provide includes:

  • the age of the solar installation;
  • panel capacity;
  • inverter make and model;
  • annual solar generation;
  • annual electricity consumption;
  • current electricity tariff;
  • typical daytime and evening consumption;
  • whether you own an electric vehicle;
  • whether you intend to install other electrical equipment.

This gives an installer considerably more information than simply asking, “How much does a solar battery cost?”

Solar and battery installation for new-builds and renovations

Battery storage can also be considered as part of a wider electrical design for a new home or major renovation.

This may be particularly useful where the property is expected to have several significant electrical loads, such as:

  • an electric vehicle charger;
  • an air-source heat pump;
  • an induction cooker;
  • electric heating;
  • a hot-water cylinder;
  • home office equipment;
  • other high-consumption electrical appliances.

The system should be designed around the property’s expected electricity demand rather than treating the solar installation as an isolated project.

Solar and battery systems for businesses in Cornwall

Solar and battery storage is not restricted to domestic properties.

Businesses may have significant daytime electricity consumption, making solar PV particularly useful where generation can be consumed directly on site.

Battery storage can add another dimension by allowing electricity generated at one time to be used later.

Commercial applications can include:

  • offices;
  • workshops;
  • farms;
  • warehouses;
  • hotels;
  • holiday accommodation;
  • retail premises;
  • industrial buildings;
  • community buildings;
  • agricultural businesses.

For larger commercial projects, the system design becomes considerably more complex and may involve demand analysis, three-phase electrical systems, export limitations, network requirements and more sophisticated energy-management systems.

See our page for Commercial Solar Installers in Cornwall if you are considering a larger business installation.

Solar and battery installation for farms and rural properties

Cornwall has a large number of rural properties, farms and agricultural businesses where solar PV and battery storage may be worth considering.

Large roofs on agricultural buildings can potentially provide substantial areas for solar generation.

However, agricultural and rural installations can involve additional considerations, including:

  • large electricity loads;
  • three-phase supplies;
  • agricultural buildings;
  • long cable runs;
  • export constraints;
  • equipment location;
  • grid connection requirements;
  • future expansion.

An installer experienced with agricultural and commercial solar projects may therefore be more appropriate for a large farm installation than a contractor whose work is primarily domestic.

MCS and choosing a solar installer

When comparing installers, homeowners should check the qualifications, certification and experience relevant to the proposed installation.

The Microgeneration Certification Scheme (MCS) has specific standards covering battery storage installations. Its battery storage standard includes requirements relating to electrical safety, grid connection and relevant technical standards.

For consumers, it is sensible to ask an installer:

  • Are you MCS certified for the work you are proposing?
  • What battery systems do you install?
  • How long have you been installing battery storage?
  • Who will carry out the electrical work?
  • What warranties apply?
  • What monitoring system is included?
  • Will you handle the relevant network notifications?
  • What happens if the battery or inverter develops a fault?
  • Can the system be expanded later?

Certification is useful, but it should be considered alongside the installer’s experience, system design and after-sales service.

DNO requirements

Battery installations can have implications for the property’s connection to the electricity distribution network.

MCS’s battery standard references the relevant Engineering Recommendations, including G98, G99 and G100 depending on the characteristics of the installation and whether export limitation is required.

Your installer should explain whether any notification or approval is required for your particular installation and should deal with the relevant process where appropriate.

This is particularly important when installing substantial solar generation and battery capacity together.

How much does solar and battery installation cost?

There is no reliable single price for solar and battery installation in Cornwall.

The total cost depends on the size and specification of the system and the complexity of the installation.

Factors include:

  • number and type of solar panels;
  • solar PV capacity;
  • battery capacity;
  • inverter type;
  • roof type;
  • roof accessibility;
  • electrical work required;
  • cable runs;
  • scaffolding;
  • consumer-unit upgrades;
  • monitoring equipment;
  • EV charging integration;
  • DNO requirements;
  • commercial versus domestic installation.

Rather than comparing battery prices alone, ask installers to provide a complete system quotation showing the equipment, installation work, warranties and expected system performance.

VAT on solar panels and batteries

VAT treatment is another factor to consider when comparing quotations.

HMRC currently lists solar panels and electrical storage batteries among energy-saving products eligible for the temporary zero rate in Great Britain under the relevant conditions. The current zero-rate period runs until 31 March 2027.

HMRC also specifically explains that a combined installation of solar panels and a battery can be treated as a single supply where the battery is ancillary to the solar installation.

The precise VAT treatment can depend on the circumstances, so your installer should make clear how VAT has been calculated in the quotation.

Questions to ask a solar and battery installer

Before choosing an installer, ask for clear answers to questions such as:

How much solar generation do you expect the system to produce?

A quotation should ideally provide an estimated annual generation figure rather than simply listing the panel capacity.

How much battery storage do I actually need?

The recommendation should be based on your electricity consumption and intended use.

What percentage of my solar electricity do you expect me to use myself?

This can help you understand the likely effect of adding battery storage.

Can the battery be expanded later?

Some systems are designed to accommodate additional battery modules.

Can the battery charge from the grid?

This may be important if you want to take advantage of time-of-use electricity tariffs.

What happens during a power cut?

Do not assume that a battery automatically provides backup electricity. Backup functionality depends on the equipment and system design and may require additional equipment.

What warranties are included?

Ask separately about panel, inverter and battery warranties.

Who provides after-sales support?

This is particularly important because batteries and inverters contain sophisticated electronic equipment.

Solar and battery installation across Cornwall

Solar and battery installers operate throughout Cornwall, including:

  • Truro
  • Newquay
  • Falmouth
  • Penzance
  • St Austell
  • Redruth
  • Camborne
  • Bodmin
  • Helston
  • Liskeard
  • Bude
  • Wadebridge
  • Launceston
  • Saltash
  • Penryn
  • Hayle
  • St Ives
  • Callington
  • Looe
  • Padstow.

Some installers are willing to travel significant distances for larger installations, while others concentrate on particular parts of Cornwall.

When requesting quotations, confirm that the installer regularly works in your area and is experienced with the type and scale of system you are considering.

Finding solar and battery installers in Cornwall

Choosing a solar and battery installer is about more than finding someone who can put panels on a roof.

The installer needs to understand the complete energy system: generation, consumption, battery storage, inverter operation, electrical safety, grid connection and future energy use.

For a new installation, ask several installers to assess the property and provide comparable system designs. If you already have solar panels, ask whether your existing system can be integrated with a new battery before committing to replacement equipment.

Trusted Tradesman is building its network of solar specialists so that homeowners and businesses looking for solar and battery installation in Cornwall can discover relevant local installers and examine the services they offer.

Related solar services in Cornwall

If you are researching solar and battery systems, you may also want to explore:

The distinction between these services is useful when choosing an installer. Some companies specialise in complete new solar-and-battery installations, while others concentrate on battery retrofits, maintenance, repairs or commercial systems.

Looking for a solar and battery installer in Cornwall? Browse local solar businesses, compare the services they provide and contact installers directly to discuss your property and requirements.