Authorised Fox ESS Installer · Cornwall
Fox ESS Battery Installation in Cornwall
Fox ESS ECS — modular, scalable lithium battery storage that grows with your needs. CCS is a Fox ESS Pro Installer for Cornwall.
Fox ESS has rapidly become one of the UK's most popular residential battery brands thanks to its modular ECS (Energy Cube System) architecture, competitive pricing, broad inverter compatibility, and strong UK technical support from its Stockport-based UK office. CCS Heating & Renewables is a Fox ESS Pro Installer with full training across the ECS battery range, the All-in-One inverter+battery family, and the H1/H3 hybrid inverter portfolio. Fox is the right answer for Cornish customers who want flexibility — to start with a smaller battery and expand later, to choose between AC and DC coupling without locking into a single ecosystem, or to run a three-phase system in larger rural Cornish properties. The ECS battery comes in 2.9kWh module increments (HV2600 high-voltage modules) which stack together within a master controller cabinet to provide configurations from 5.8kWh up to 23.3kWh per cabinet. Multiple cabinets can be paralleled for installations up to 70kWh+ — comfortably covering off-grid-leaning Cornish smallholdings or commercial premises. All Fox ESS batteries qualify for 0% VAT under the green technologies relief, carry a 10-year manufacturer warranty (with 80% capacity retention guarantee), and are MCS-certified for grid connection. Fox's emergency power supply (EPS) function gives basic backup capability during grid outages — relevant in storm-prone rural Cornwall. Combined with Fox H1/H3 hybrid inverters and the FoxCloud monitoring platform, the ECS provides a complete energy management solution at price points 30–40% below Tesla equivalents.
Key Specifications
| Module capacity | 2.9kWh per HV2600 module |
| Cabinet capacity | 5.8kWh – 23.3kWh (2–8 modules) |
| Multi-cabinet capacity | Up to 70kWh+ paralleled |
| Cell chemistry | LFP (lithium iron phosphate) |
| Round-trip efficiency | 97% DC-coupled / 92% AC-coupled |
| Cycles | 6,000+ to 80% capacity (10-year warranty) |
| Operating temperature | -10°C to +50°C |
| EPS backup | Yes (with H1/H3 hybrid inverter) |
| Three-phase compatible | Yes (with H3 inverter) |
| Warranty | 10 years (80% capacity retention guarantee) |
Modular ECS architecture explained
Fox ESS's signature feature is the modular ECS battery cabinet. Each cabinet contains a master controller (Mira HV5000) and 2–8 stacked HV2600 battery modules (2.9kWh each). This means you can specify exactly the capacity you need today — say 8.7kWh (3 modules) — and add additional modules later as your needs grow, without replacing the master controller or rewiring the system. Adding a module typically takes a CCS engineer 90 minutes and costs around £1,400 for the module itself plus minimal labour.
This modularity is particularly valuable in Cornwall because energy needs evolve rapidly: today's solar-only customer may add a heat pump in 2 years and an EV in 4 years. Each addition justifies more storage. With a Fox ECS, you scale up incrementally rather than paying for capacity you don't yet need.
AC vs DC coupling options
Fox ESS supports both AC and DC coupling. For new solar plus storage installations, we typically specify the Fox H1 (single-phase 3.0–6.0kW) or H3 (three-phase 5.0–15.0kW) hybrid inverter, which integrates solar MPPT and battery management in one device — DC-coupled for maximum efficiency (around 97% round-trip). For retrofitting storage to an existing solar PV system, we use the Fox AC1 inverter to AC-couple the ECS battery alongside your existing string inverter — typically achieving 92–93% round-trip efficiency.
The H3 three-phase inverter is particularly relevant for larger rural Cornish properties on three-phase grid supply (common in farms, large country homes, and properties with grid-tied EV charging plus heat pumps). Fox is one of very few brands offering true residential three-phase hybrid inverters at sensible price points. See our battery storage overview.
FoxCloud monitoring and tariff optimisation
FoxCloud is Fox ESS's free smartphone and web monitoring platform. Real-time view of solar generation, battery state-of-charge, household consumption, and grid import/export — with historical trending and energy reports. FoxCloud also supports time-of-use scheduling for Octopus Cosy, Flux and Agile tariffs, automatically scheduling battery charge during cheap windows and discharge during expensive periods.
For households on Octopus Flux, the typical Cornish ECS owner achieves additional savings of £400–£700/year purely from tariff arbitrage on top of the solar self-consumption savings. CCS configures FoxCloud and tariff schedules during commissioning, providing a written user guide tailored to your installation.
Emergency power supply (EPS) for Cornish storms
Cornwall's exposed Atlantic position means winter Atlantic storms regularly cause grid outages — particularly in West Cornwall (TR19, TR20), the Lizard (TR12), and rural North Cornwall (PL30, PL35). The Fox ECS battery, paired with a Fox hybrid inverter, includes built-in EPS (Emergency Power Supply) functionality — when the grid fails, a dedicated EPS output continues powering essential circuits from the battery and any available solar.
EPS is not full whole-home backup like the Tesla Powerwall 3 — it's typically wired to specific essential circuits (fridge/freezer, lighting, broadband router, gas boiler controls) totalling 3–5kW. For Cornish customers wanting full whole-home backup, we recommend either a Tesla Powerwall 3 or a more sophisticated Fox configuration with manual transfer switching. CCS designs EPS arrangements based on your specific resilience needs.
Three-phase installations for rural Cornwall
Many rural Cornish properties — farms, larger country homes, properties with multiple outbuildings — are connected to three-phase grid supply. Three-phase is also increasingly common in larger new-build developments. Fox ESS's H3 series hybrid inverter (5kW, 8kW, 10kW, 12kW, 15kW three-phase outputs) is the most cost-effective true three-phase residential hybrid on the UK market today.
For these installations, we typically pair the H3 inverter with a single ECS cabinet (up to 23.3kWh) or paralleled cabinets for larger storage requirements. The whole installation is balanced across the three phases for stable export and import behaviour.
Fox ESS Models We Install
Individual battery module — stack 2–8 within a master cabinet to build your required capacity.
Most popular Cornish residential entry point. Pairs perfectly with 4–6kW solar PV.
Mid-sized cabinet for solar + heat pump or solar + EV households.
Maximum single-cabinet capacity. Suits high-consumption households or off-grid-leaning installs.
True three-phase residential hybrid inverter for rural Cornish properties on 3-phase supply.
Fox ESS battery installation pricing in Cornwall
Typical fully installed pricing (May 2026):
- ECS 8.7kWh + H1 5kW hybrid inverter (no PV) — from £6,800
- ECS 8.7kWh + new 5kW solar PV system — from £11,200
- ECS 14.5kWh + new 6kW solar PV system — from £13,800
- ECS 23.3kWh + new 10kW solar PV system — from £17,500
- ECS 14.5kWh + H3 8kW three-phase hybrid (rural) — from £12,400
- Adding an extra HV2600 module to existing system — £1,650 fitted
All prices include 0% VAT, MCS commissioning, DNO G98/G99 notification, and FoxCloud monitoring setup. Modular pricing is a key Fox advantage — no other major brand lets you genuinely scale up incrementally. See our finance options.
Warranty
10 years parts & labour with guaranteed 80% capacity retention at year 10. Inverter 10-year warranty.
Why Choose CCS for Fox ESS?
CCS is a Fox ESS Pro Installer with extensive ECS commissioning experience across Cornwall. Our engineers carry full Fox training, we have direct UK technical escalation, and we maintain stocked Fox modules at our Pool depot for fast capacity expansion or warranty service. Fox is our recommended choice for customers prioritising modular scalability and value-for-money.