
Electric11 added 10.36 kWh of Fox ESS battery storage to an existing residential solar system in Barnt Green. The battery was integrated with the property’s compatible Fox ESS hybrid inverter, allowing more surplus solar electricity to be retained for later household use. External mounting, protected cabling and local isolation created a compact installation without occupying indoor space.
Project Overview
| Project detail | Information |
| Project type | Battery retrofit for an existing solar PV system |
| Location | Barnt Green, Birmingham |
| Property type | Residential |
| Existing equipment | Solar panels and Fox ESS hybrid inverter |
| Added equipment | Fox ESS high-voltage battery storage |
| Working battery capacity | 10.36 kWh |
| Installation position | Exterior brick wall |
| Completion date | 20 May 2025 |
Adding Storage to the Existing Solar System
The home already generated renewable electricity through its solar panels. Without battery storage, electricity not used when generated would typically be exported to the grid. The customer wanted to retain more of that surplus energy and make it available when household demand increased or solar production fell.
Electric11 assessed the existing hybrid inverter and planned a compatible battery retrofit. This approach retained the established solar equipment while adding a new storage component to the home-energy system.
Homeowners considering a similar retrofit can learn more about Electric11’s home battery storage systems, including compatibility checks, battery sizing and integration with existing solar installations.
Checking Inverter and Battery Compatibility
A battery retrofit depends on more than finding available wall space. The existing inverter must support the proposed battery voltage, communication method and operating configuration.
For this project, the Fox ESS battery was integrated with the property’s existing Fox ESS hybrid inverter. Keeping the equipment within the same manufacturer ecosystem supported direct communication between the inverter and battery while avoiding an unnecessary replacement of the functioning solar array.
The battery model must still be confirmed from the commissioning pack. The available job notes refer to both the Fox ESS EP5-H and EP11-H, but the installed unit’s wider proportions are more consistent with an EP11-format battery.
Installing the Fox ESS Battery
Electric11 positioned the battery beneath the existing inverter on the home’s exterior brick wall. This arrangement kept the related equipment together and maintained accessible space around the inverter, battery connections and isolator.
The installation photographs show:
A wall-mounted Fox ESS hybrid inverter
A floor-supported or low-mounted Fox ESS battery
A dedicated rotary isolator
Protected external cable runs
Labelled inverter and battery connections
Neat routing between the existing inverter and new storage unit
The selected position also avoided using internal living or storage space for the new equipment.
Integrating Battery Storage With Solar PV
The hybrid inverter coordinates how electricity moves between the solar panels, battery, home and grid. During periods of surplus solar generation, the system can direct available electricity into the battery. Stored energy can then support household demand when solar output drops, subject to the selected operating mode and state-of-charge settings.
This type of retrofit can increase solar self-consumption without changing the roof-mounted array. It may also support scheduled off-peak charging when paired with a suitable time-of-use tariff and correctly configured battery settings.
Electric11’s Fox ESS app setup guide explains how homeowners can monitor solar generation, battery charge, household consumption and grid activity after commissioning.
Expected Energy and Cost Benefits
Using a 10.36 kWh battery as the working assumption, the system could store or shift approximately 3,200 kWh of electricity each year. At an indicative value of around 18 pence per shifted kilowatt-hour, that equates to estimated annual savings of approximately £580.
The projected carbon benefit is also estimated at 580 kg per year. Both figures depend heavily on how much surplus solar electricity is available, how frequently the battery cycles and how the household’s import and export tariffs compare.
The battery does not generate new electricity. Its value comes from increasing the proportion of existing solar production used within the property and, where appropriate, shifting lower-cost grid electricity to periods when tariffs are higher.
The Result
The Barnt Green home gained a compact battery storage system integrated with its existing solar installation and hybrid inverter. The exterior arrangement kept the equipment accessible while preserving indoor space.
The retrofit gives the customer greater control over surplus solar electricity and more flexibility over when stored energy supports the home. It also provides a scalable foundation if the household’s energy demand changes in the future, subject to the limits of the confirmed inverter and battery models.
Visitors comparing different storage projects can also view Electric11’s Pylontech battery storage upgrade, which demonstrates how an established system can gain additional capacity without replacing its core inverter equipment.
Request a Battery Storage AssessmentElectric11 is composed of a team of local electricians based in Attleborough, offering coverage to the entire Norfolk region. Moreover, through our extensive network, we have forged strong connections with quality tradesmen representing various disciplines in our area.
The Electric11 Battery Storage Installation Process
Electric11 approaches battery retrofits through four defined stages, covering compatibility, system design, installation and final handover.
Solar and Electrical Assessment
An electrician reviews the existing panels, inverter, consumer unit, available installation space and household energy profile. This identifies whether the current equipment supports a battery retrofit and what capacity may suit the property.
Clear Battery Options and Quote
The customer receives a quotation covering the recommended battery, electrical components, installation work and any required upgrades. Capacity options and practical differences are explained before the customer selects a system.
Battery Installation and Integration
The team installs the battery, isolator, cabling and communication connections in the agreed positions. The new storage unit is then integrated with the existing hybrid inverter and solar PV setup.
Commissioning Monitoring and Handover
The completed system is commissioned and configured for the selected operating strategy. The customer receives monitoring guidance, operating information and the applicable installation documentation.





