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2,000+ Solar & Battery Installations Completed in the North East.

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Mr Capstick – Battery Retrofit Installation

Fox ESS Cube 17.2kWh Storage System

Sustainable Energy Engineering Ltd carried out a complete battery retrofit installation for Mr Capstick, supplying and commissioning a full Fox ESS Cube storage system. This upgrade included the installation of a master battery unit and three slave modules, providing a total usable capacity of 17.2kWh.

The installation also included a Fox ESS AC charger, automatic gateway, WiFi monitoring equipment, CT clamp, full labelling, and commissioning documentation. All batteries and the charger were warranty-registered as part of the installation process.

This retrofit enables the customer to maximise solar generation, charge during off-peak periods, and significantly reduce grid dependence.

Technical Information:

Battery System:Fox ESS Cube 17.2kWh Total Capacity
Master Battery:1 × Fox ESS Cube 4.3kWh
Slave Batteries:3 × Fox ESS Cube 4.3kWh
AC Charger:Fox ESS 3.7kW AC Charger
Automatic Changeover:Fox ESS Gateway
Monitoring:Fox ESS WiFi Dongle + CT Clamp
Safety Components:Battery Warning Labels, Earth Rod
Documentation:Full commissioning pack + warranty registration


Project Gallery:

Cut Your Energy Bills - Start Today.

2,000+ Solar Installs Completed in the North East.

CALL 0191 340 7001


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We've helped homeowners across the North East cut energy bills and reduce carbon emissions with bespoke domestic solar systems, from family homes to larger residential properties. Alongside this, we've delivered projects for schools like Cragside and Dame Dorothy, community hubs such as Kibblesworth Millennium Centre and Alnwick Community Centre, local cafes, churches, and even national brands like Burger King. With major installs for organisations including Darlington College, Phillips Pet Supplies, and Collingwood Healthcare Services, our portfolio shows proven expertise across both domestic and commercial solar - providing tailored installations that deliver long-term savings and sustainability.

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To design and size your solar and/or battery system correctly, we need to know your annual kWh usage. This allows us to create a system that accurately matches your energy needs - reducing the electricity you buy from the grid, lowering your carbon footprint, and protecting you from rising energy costs so you save as much money as possible.

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With hundreds of five-star reviews since 2006, Sustainable Energy Engineering has built a reputation for quality, honesty, and reliability. Unlike many short-lived installers, we're here for the long haul - ready to support you long after installation. That's why so many customers choose us after their original installer disappears. Choose us for peace of mind, fair pricing, and expert solar solutions that last.