How Does Solar Battery Storage Work?

 

Solar panels generate electricity during daylight hours. The home will normally use that electricity first, with any surplus either exported to the grid or stored in a solar battery.

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A typical solar battery storage system works by:

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• generating electricity from solar panels;

• supplying electricity directly to the home;

• storing surplus solar generation in the battery;

• using stored electricity later when solar output falls; and

• drawing electricity from the grid when solar and battery power are insufficient.

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The aim is to increase the amount of electricity generated and used within the property rather than exporting surplus energy and buying it back later at a higher price.

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Home Battery Storage

 

Home battery storage is not limited to properties with solar panels.

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A battery can also be charged using electricity from the grid, which can be particularly useful with time-of-use tariffs where electricity prices vary during the day.

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For example, a battery may be charged during cheaper overnight periods and used when grid electricity becomes more expensive.

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Where solar panels are installed, the battery can potentially combine both approaches by storing surplus solar electricity and taking advantage of lower-cost grid charging when appropriate.

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Solar Batteries for the Home

 

There are now many solar batteries for home use, with different capacities, power outputs, warranties and control systems.

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When comparing home batteries, it is worth considering:

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• usable battery capacity;

• maximum charge and discharge rate;

• battery chemistry;

• expected lifespan;

• warranty;

• inverter requirements;

• monitoring and controls;

• compatibility with solar panels;

• smart tariff integration;

• backup-power capability; and

• opportunities for future expansion.

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The largest battery is not automatically the best choice. A good solar battery for a house should be matched to the electricity use and generation profile of the property.

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Solar Panels With Battery Storage

 

Solar panels with battery storage can provide a more flexible home energy system than solar panels alone.

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Without battery storage, surplus solar electricity that is not used immediately may be exported to the grid. A battery allows some of that electricity to be retained and used later.

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This can be particularly useful for households where electricity consumption is relatively low during the day but increases during the evening.

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Solar panels and battery storage should ideally be considered together because the size of the solar array, battery capacity, inverter equipment and household demand all influence how effectively the system will perform.

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Is Solar Battery Storage Worth It?

 

Whether solar battery storage is worthwhile will depend on the individual home.

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Important factors can include:

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• size of the solar installation;

• amount of surplus solar electricity;

• household electricity consumption;

• when electricity is used;

• electricity tariffs;

• export payments;

• battery capacity;

• installation cost;

• expected battery lifespan;

• EV charging;

• heat-pump use; and

• future household electricity demand.

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A property that exports large amounts of solar electricity during the day and then buys electricity back from the grid during the evening may benefit more from battery storage than a property that already uses most of its solar generation directly.

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How Much Does a Solar Battery Cost?

 

Solar battery cost varies considerably depending on capacity, manufacturer, technology and the complexity of the installation.

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The total cost of a home battery storage system may be influenced by:

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• battery capacity;

• battery manufacturer;

• inverter equipment;

• electrical alterations;

• installation location;

• cable routes;

• monitoring equipment;

• backup-power requirements;

• integration with existing solar panels; and

• whether the battery is installed at the same time as a new solar system.

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Homeowners should compare more than the initial purchase price.

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Warranty length, usable capacity, expected degradation, efficiency, software support and compatibility with future equipment can all affect long-term value.

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What Size Solar Battery Does a House Need?

 

The appropriate battery size will depend on how much electricity the home uses and when that electricity is required.

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Factors to consider include:

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• average daily electricity consumption;

• solar-panel system size;

• typical surplus solar generation;

• evening and overnight electricity demand;

• EV charging;

• heat-pump use;

• air conditioning;

• future electrical appliances; and

• budget.

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A battery that is too small may regularly fill during sunny periods and leave significant surplus generation available for export.

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A battery that is unnecessarily large may rarely be fully charged or discharged and can represent poor value.

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The aim should be to choose battery capacity that matches the likely generation and consumption pattern of the property.

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Solar Battery Storage Systems

 

A solar battery storage system involves more than the battery itself.

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Depending on the design, the system may include:

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• battery modules;

• solar inverter;

• battery inverter;

• monitoring equipment;

• isolation equipment;

• control software;

• electrical protection;

• metering; and

• optional backup-power equipment.

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The way these components are designed and integrated can affect system efficiency, future flexibility and how easily additional equipment can be added later.

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Can You Add Battery Storage to Existing Solar Panels?

 

In many cases, yes.

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A homeowner who already has solar panels may be able to add home battery storage to the existing installation.

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The most suitable approach will depend on:

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• age of the solar system;

• existing inverter;

• available electrical capacity;

• battery type;

• available space;

• cable routes; and

• future energy plans.

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Some systems can accept a battery relatively easily. Others may require additional inverter equipment or changes to the original installation.

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The existing solar installation should therefore be reviewed before choosing a battery.

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Do You Need Solar Panels to Install a Battery?

 

No.

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A home battery can operate independently of solar panels.

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Grid-charged home battery storage can allow electricity to be purchased at cheaper times and used later when tariffs are higher.

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However, combining solar panels with battery storage can provide the additional benefit of storing electricity generated directly by the property.

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For many homeowners, the most useful approach is to consider both technologies together even if they are installed at different stages.

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Solar Battery Storage and EV Charging

 

Electric vehicles can significantly increase household electricity consumption.

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Battery storage can help manage when electricity is used, particularly where an EV is normally charged in the evening.

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For example, solar panels may generate electricity during the day, some of which charges the home battery. Stored electricity can then contribute towards charging the vehicle later.

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However, an electric vehicle battery is considerably larger than most domestic home batteries, so EV charging can quickly use the available stored electricity.

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Solar generation, home battery storage and EV charging should therefore be considered as one overall energy system.

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Solar Batteries and Heat Pumps

 

Heat pumps increase household electricity demand because they use electricity to provide heating and hot water.

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Solar panels and battery storage may help contribute towards this additional demand.

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However, the greatest heating demand normally occurs during winter when solar generation is lower, so a home battery should not be viewed as a complete solution to heat-pump electricity consumption.

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The value lies in coordinating solar, battery storage, heating demand and electricity tariffs as effectively as possible.

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Home Batteries and Smart Energy Tariffs

 

Smart electricity tariffs can significantly affect the way battery storage is used.

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Some tariffs offer cheaper electricity during particular periods of the day or night.

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A battery may therefore be charged when electricity is cheaper and discharged when grid electricity becomes more expensive.

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Modern battery systems can increasingly automate this process using smart controls.

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This can mean that the battery is used not only for storing solar energy but also for managing the cost of grid electricity.

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Can Solar Battery Storage Provide Backup Power?

 

Some solar battery storage systems can provide backup electricity during a power cut, but not all systems offer this capability.

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The ability to provide backup power depends on:

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• battery equipment;

• inverter design;

• electrical installation;

• isolation equipment; and

• whether dedicated backup circuits have been provided.

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A standard grid-connected solar system may automatically shut down during a power cut for safety reasons.

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If backup power is important to you, this should be discussed during the system design stage.

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Where Can a Home Battery Be Installed?

 

Possible battery locations can include:

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• garages;

• utility rooms;

• plant rooms;

• suitable internal spaces;

• external walls;

• dedicated enclosures; and

• other suitable protected locations.

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The installation should take account of ventilation, temperature, access, electrical connections, manufacturer requirements and fire safety considerations.

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The battery should be positioned as part of the electrical design rather than simply wherever space happens to be available.

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Do Solar Batteries Need Planning Permission?

 

Domestic battery storage will not usually be one of the more complex planning elements of a home energy project, but the circumstances of the property can still matter.

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Listed buildings, flats, leasehold properties, sensitive locations and externally positioned equipment may require additional consideration.

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Where battery storage forms part of a larger solar, heat-pump or green home installation, it is sensible to consider the planning position for the overall project.

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Solar Battery Installation and Electrical Requirements

 

Home battery storage is a significant electrical installation and should be properly designed and installed.

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The electrical design may need to consider:

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• existing consumer unit;

• available electrical capacity;

• inverter compatibility;

• isolation;

• earthing;

• cable routes;

• metering;

• system controls;

• export arrangements; and

• future electrical demand.

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Where a property may eventually include solar panels, batteries, EV charging, heat pumps and air conditioning, the overall electrical demand should be considered from the outset.

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Battery Lifespan and Warranty

 

Solar batteries are designed to charge and discharge repeatedly over many years, but usable capacity will gradually reduce.

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Battery warranties may be based on:

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• number of years;

• number of charge cycles;

• total energy throughput;

• retained capacity; or

• a combination of these factors.

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Homeowners should therefore compare the warranty and expected long-term usable capacity as well as the initial battery size.

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Should You Install Solar Panels and a Battery at the Same Time?

 

Installing solar panels and battery storage together can have several advantages.

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The equipment can be designed as one integrated system, electrical work can be coordinated and the battery can begin storing surplus solar electricity immediately.

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However, installing the battery later can also be sensible.

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Some homeowners choose to install solar panels first, monitor how much electricity is being generated and exported, and then use that information to decide whether battery storage represents worthwhile additional investment.

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There is no single approach that suits every home.

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Solar Battery Storage as Part of a Green Home Plan

 

Home battery storage becomes particularly useful when a property is moving towards greater use of electricity.

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A future green home may include:

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Solar panels generating electricity.

Home battery storage retaining surplus energy.

An EV charger supplying an electric vehicle.

A heat pump providing heating and hot water.

Air conditioning increasing summer electricity demand.

Smart controls managing when electricity is generated, bought, stored and used.

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Considering these technologies together can help create a more flexible and efficient home energy system.

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Independent Solar Battery Advice

 

Battery installers naturally focus on supplying and installing battery systems.

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Our role is broader.

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A Green Home Survey can help you consider whether solar battery storage is appropriate, what size battery may be worth investigating, whether it should be installed now or later and how it could work alongside solar panels, EV charging, heating and other home improvements.

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The objective is to understand what is appropriate for your property before committing to expensive equipment.

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Start With Your Home Energy Use

 

The best home battery is not necessarily the biggest or most expensive battery.

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It is the battery that works effectively with the way your home generates and consumes electricity.

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Before investing in solar battery storage, it makes sense to understand your solar potential, household electricity use, future energy demand and the other technologies you may want to introduce.

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NEXT STEPS

Every home is different, so the right next step depends on your property, your budget and what you want to achieve. APN Green Homes can help you turn the information you have just read into a practical plan for your own home. Whether you are considering one improvement or looking at a complete whole-home energy upgrade, we can help you understand what is suitable, what should be prioritised and where your money is likely to make the greatest difference.

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Choose one of the options below to get the ball rolling:

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BOOK A GREEN HOME SURVEY
Get a detailed assessment of your home with practical, property-specific recommendations and a clear plan for the improvements worth considering.

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BOOK A PHONE CONSULTATION
Talk through your property, ideas and priorities with us and get some initial direction on the best way forward.

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EMAIL US
Send us details of your property, photographs or any questions and we can advise you on the most appropriate next step.

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GIVE US A CALL
Prefer to speak to someone? Give us a call and tell us what you are hoping to achieve.

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Your greener, more efficient home starts with understanding the right improvements for your property — and putting them in the right order.