Flat Roof Solar Installation in Sevenoaks: 11.16kW Solar with 41.9kWh Storage
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The Sunbright Energy team recently completed a large solar and battery installation for a homeowner in Sevenoaks, Kent.
Unlike a typical residential installation on a pitched roof, this system was designed around a substantial flat-roof area. The finished installation combines 24 high-efficiency Aiko solar panels with a 10kW Fox ESS hybrid inverter and nine Fox ESS battery modules.
Together, the system provides 11.16kW of solar capacity and 41.9kWh of battery storage.
The property uses approximately 16,800kWh of electricity each year, so a small, standard system would not have been sufficient. Instead, we designed the installation around the homeowner’s higher energy demand, available roof space and opportunity to use time-of-use electricity tariffs.
It is an excellent example of how a carefully designed flat-roof solar system can deliver substantial generation, lower grid reliance and much greater control over household energy costs.
System Size
Solar Generation
Total Savings
Project Overview
Location: Sevenoaks, Kent
Solar array: 11.16kW
Solar panels: 24 × Aiko Neostar 2S 465W All Black panels
Inverter: Fox ESS KH 10kW single-phase hybrid inverter
Battery storage: 9 × Fox ESS EQ4800 modules
Total battery capacity: 41.9kWh
Expected annual solar generation: 10,467kWh
Annual household electricity consumption: 16,800kWh
Estimated annual CO₂ reduction: 2,155kg
Are Flat Roofs Suitable for Solar Panels in Sevenoaks?
Some homeowners in Sevenoaks assume that a flat roof is less suitable for solar than a conventional pitched roof. In practice, a flat roof can provide an excellent platform for a solar installation when the array is designed correctly.
On a pitched roof, panel orientation and angle are largely dictated by the building itself. A flat roof can give the designer more flexibility over how the panels are positioned.
Depending on the property, this can make it possible to optimise:
- Panel angle and orientation
- Spacing between rows
- Shading management
- Access for maintenance
- Overall system capacity
The mounting design must still account for wind loading, roof structure, drainage and the possibility of one row shading another. It is therefore important that a flat-roof installation is properly surveyed and engineered rather than treated as a standard pitched-roof project.
For this Sevenoaks property, the available space allowed us to create a large 24-panel array capable of generating more than 10,000kWh of electricity in a typical year.
Designing for a High-Energy-Use Home
This property consumes around 16,800kWh of electricity annually, which is considerably more than many standard households.
That level of consumption meant the system needed to do more than produce electricity during sunny daytime periods. It also needed to make energy available later in the day and provide enough storage capacity to support smart battery management.
The design objectives were clear:
- Generate a meaningful proportion of the property’s annual electricity
- Store excess solar production for later use
- Reduce reliance on expensive peak-rate grid electricity
- Take advantage of cheaper time-of-use tariffs
- Give the homeowner greater control over long-term energy costs
This is why the installation combines a large solar array with almost 42kWh of battery storage.
The System in Sevenoaks
24 Aiko Neostar 2S Solar Panels
The array uses 24 Aiko Neostar 2S 465W All Black ABC N-Type Mono solar panels.
Together, these provide a total installed solar capacity of:
11.16kW
Aiko panels are a strong option where high output and efficient use of roof space are priorities. Their all-black finish also provides a clean, consistent appearance, while the high panel rating allowed us to create a substantial array without requiring an excessive number of individual modules.
The system is expected to generate approximately 10,467kWh of clean electricity each year.
Actual generation will naturally vary according to weather conditions, seasonal sunlight, shading and system performance, but the estimate provides a realistic basis for modelling the homeowner’s likely savings.
Fox ESS KH 10kW Hybrid Inverter
The panels are connected to a Fox ESS KH 10kW single-phase hybrid inverter.
The inverter converts the direct-current electricity produced by the panels into alternating-current electricity that can be used within the property.
As a hybrid inverter, it also manages the interaction between the solar array, battery system, household demand and electricity grid. It decides whether available solar energy should be used immediately, stored in the batteries or exported.
This integrated approach gives the homeowner a much more flexible energy system than solar panels alone.
41.9kWh of Fox ESS EQ4800 Battery Storage
The installation includes a stack of nine Fox ESS EQ4800 battery modules, providing a combined usable storage capacity of approximately 41.9kWh.
This is a substantial battery system, but it is appropriate for a home consuming 16,800kWh per year.
A smaller battery could fill quickly on a sunny day and might not provide enough stored energy to cover the property’s larger evening and overnight loads. The larger EQ4800 system gives the homeowner far more scope to store solar generation and charge from the grid when electricity is cheaper.
The stackable EQ format also makes it well suited to installations where a high storage capacity is required without spreading multiple separate batteries across a large area.
At Sunbright Energy, Fox ESS are always our go to inverter & battery brand thanks to their reliability, high efficiency and fantastic customer service.
Sunbright Energy are also the only Fox ESS Approved Installer in Kent.
Thinking about FOX ESS FOR YOUR PROPERTY?
Sunbright Energy are the only Fox ESS Approved Partner in Kent
How the System Is Expected to Perform
Our detailed energy model estimates annual solar generation of around 10,467kWh.
Of the energy produced by the panels, approximately:
- 4,494kWh is expected to be used directly in the home
- 1,483kWh is expected to pass through battery storage
- 4,430kWh is expected to be exported to the grid
The property’s total annual consumption is approximately 16,800kWh. The model predicts that this demand will be supplied by:
- 4,494kWh from solar directly
- 8,828kWh through the battery
- 3,478kWh directly from the grid
The larger battery figure includes energy managed through the battery across the year, including electricity that may be charged from the grid during cheaper tariff periods. It is therefore not limited to solar energy stored during the day.
This distinction is important. Battery storage is not only being used to retain surplus solar electricity; it is also acting as an energy-management tool.
Estimated Electricity Bill Savings
Before the installation, the homeowner’s annual electricity bill was modelled at approximately:
£5,292
After installing the solar and battery system and moving from a flat tariff to a suitable variable tariff, the projected annual bill falls to:
£2,017
That represents an estimated first-year saving of:
£3,275
The homeowner may also receive payments for eligible electricity exported through the Smart Export Guarantee. Based on the assumptions used in the proposal, export payments could reduce the effective annual electricity cost to approximately £1,837.
These figures are projections rather than guarantees. Actual savings will depend on energy use, future tariff rates, weather, export payments and how the system is operated.
If you’d like a full savings estimate based on your unique home, enter your postcode below and get your savings estimate in 60 seconds:
Saving More Through Battery Management
One of the biggest advantages of installing 41.9kWh of storage is the ability to use time-of-use electricity tariffs more effectively.
Battery management allows the system to charge from the grid at fixed times when electricity is inexpensive. The stored electricity can then be used later, avoiding more expensive imports during peak periods.
For example, the batteries might charge overnight on a low-rate tariff and then power the property during the morning and evening, when electricity prices are higher.
Without scheduled battery management, the system would normally prioritise charging from surplus solar. While that still provides savings, it may leave valuable battery capacity unused during darker periods or during winter.
The project model estimates that intelligent battery management could deliver up to:
£1,379 in additional annual savings
When those projected savings are included, the property’s effective first-year electricity cost could fall to approximately:
£458
For a home consuming 16,800kWh annually, that represents a significant reduction in exposure to standard grid electricity prices.
What This Sevenoaks Project Demonstrates
This installation shows that a flat roof should not automatically be viewed as a disadvantage.
With a suitable roof structure, an appropriate mounting system and careful technical design, flat roofs can support large, productive solar arrays. In some cases, they also give the designer more control over panel positioning than a fixed pitched roof.
It also shows why solar and battery capacity should be designed around the household rather than selected from a standard package.
For this high-consumption home, the combination of an 11.16kW array and 41.9kWh battery provides several layers of value:
- Direct use of solar electricity
- Storage of surplus daytime generation
- Reduced peak-rate grid imports
- Greater use of cheaper overnight electricity
- Potential export income
- Improved long-term energy control
Thinking About Going Solar in Sevenoaks?
For homeowners in Sevenoaks, Kent and the surrounding areas, the most useful first step is a proper assessment of the roof, electricity consumption and tariff options.
At Sunbright Energy, we provide FREE detailed quote packs along with a complete savings estimate tailored to your property.
We’re based in Sevenoaks, and respond to all queries within 24 hours, every day of the week.
Thinking about solar panels FOR YOUR HOME?
Get in contact with Sunbright Energy today
Meet The Owner
Oliver Crouch – Director
“I’m Oliver, the Director of Sunbright Energy. We’re a local, family-run business in the solar industry, which I’ve proudly led since its founding in 2014.
As a family business, we value personal connections and community. We’re driven to treat every customer with the respect and attention they deserve. Don’t hesitate to start your solar journey today – get in touch with Sunbright Energy for a service you can trust.”
FAQs
Can an existing Fox ESS battery system be upgraded?
Yes. In many cases, existing Fox ESS systems can be upgraded or replaced to better suit changing energy requirements. The most suitable approach depends on your current equipment and your property’s electrical setup.
Can battery storage be installed without solar panels?
Yes. Modern battery systems can be used alongside smart electricity tariffs, allowing homeowners to store low-cost electricity overnight and use it during the day. This battery storage installation we completed in Werst Malling, Kent is a perfect example.
What is a three-phase battery storage system?
A three-phase battery storage system is designed for properties with a three-phase electricity supply, providing higher power capacity and supporting larger electrical loads than single-phase systems.
How do smart tariffs work with battery storage?
Smart tariffs offer cheaper electricity during off-peak periods. Battery systems can automatically charge when electricity is at its lowest cost and discharge when prices are higher, helping reduce overall energy bills.
Is battery storage worth it without solar?
For many homeowners, yes. When combined with suitable time-of-use tariffs, battery storage can significantly reduce electricity costs by shifting energy consumption to lower-priced periods.
