2026 Equipment Comparison · Fox ESS, Sigenergy & EcoFlow
Solar battery & panel brands we install: 2026 UK comparison
Rather than publishing a generic “top 10” list of hardware we have never fitted, this guide compares the exact residential battery, inverter and solar panel brands installed and supported by Solar City (NIC-1542): Fox ESS, Aiko, EcoFlow, Sigenergy, Trina, LONGi.
Side-by-side battery comparison: Fox ESS vs Sigenergy vs EcoFlow
All three home battery platforms we install use lithium iron phosphate (LFP / LiFePO4) cells, IP65+ weatherproof enclosures and smartphone app monitoring for time-of-use tariff scheduling. The right choice depends on your wall or floor space, expansion plans and budget:
| Feature / specification | Fox ESS (H-series + EP6 / EP12) | Sigenergy (SigenStor 5-in-1) | EcoFlow (PowerOcean) |
|---|---|---|---|
| Architecture | Separate wall-mounted hybrid inverter + wall or floor-mounted EP6 / EP12 battery pack(s) | All-in-one floor-standing stack combining Energy Controller and battery packs in one column | Modular stackable LFP battery packs with dedicated hybrid inverter |
| Usable module capacities | EP6: ~5.2 kWh usable per unit EP12: ~10.4 kWh usable per unit | SigenStor 6: 6.0 kWh usable SigenStor 9: 9.04 kWh usable | Modular ~5 kWh class LFP blocks (scalable in parallel) |
| Modularity & expansion | Up to 4 units in parallel in our design tool (from ~5.2 kWh to ~41.6 kWh usable) | Cable-free vertical plug-in stack; add modules to the column | Parallel DC-coupled modules with independent BMS per pack |
| Warranty & cycle guidance | 10-year manufacturer warranty (with Fox registration); 4,000 to 6,000+ cycle class (see Fox ESS datasheets ↗) | 10-year manufacturer warranty; 10,000+ cycle class on SigenStor cells (see Sigenergy datasheets ↗) | Up to 15-year manufacturer warranty / 6,000+ cycle class on PowerOcean (see EcoFlow UK specs ↗) |
| App & tariff scheduling | Fox Cloud 2.0 app & web portal; timed charge/discharge windows for overnight off-peak tariffs | mySigen app with AI energy scheduling, time-of-use tariff optimisation and optional EV DC/AC integration | EcoFlow app with real-time solar, battery and grid load monitoring |
| Backup / EPS support | Optional EPS switchover box for dedicated backup circuits (specified at survey if required) | Optional Sigen Gateway for whole-home or critical-load backup switchover (specified at survey) | Built-in backup output port option for designated critical circuits |
| Design tool indicative pricing | Hybrid upgrade: +£405 EP6 (~5.2 kWh): +£945 EP12 (~10.4 kWh): +£2,160 | 8x 495W AIKO + EC 3.6 kW + 6.0 kWh: £7,402.50 10x 465W AIKO + EC 5.0 kW + 6.0 kWh: £7,672.50 | Quoted on desktop design / site survey to match property layout |
Every figure is indicative, from the Solar City design tool at solarcityuk.co.uk/design. Scaffolding is extra (around £400-£500 per side) and an on-site survey confirms your final design and price.
Which battery we recommend when (by Chris Hammond)
Because we install all three platforms with our own Tyseley electricians rather than pushing a single warehouse clearance line, here is how I advise homeowners across Birmingham and Solihull to choose between them:
- Choose Fox ESS (H-series + EP6 or EP12) when: You want the strongest payback and lowest cost per usable kilowatt-hour. Adding a Fox H-series hybrid inverter (+£405) and an EP6 (~5.2 kWh usable, +£945) or EP12 (~10.4 kWh usable, +£2,160) is our most popular setup across our published West Midlands case studies. It is also ideal when garage or utility wall space suits a separate inverter and slim wall-hung battery. Read our dedicated Fox ESS guide.
- Choose Sigenergy SigenStor when: You want a single, cable-free architectural column on the garage floor or driveway wall, higher cycle ratings, and seamless future expansion or V2X / gateway options without separate conduit runs between inverter and battery boxes.
- Choose EcoFlow when: You already use the EcoFlow ecosystem or want a compact modular LFP system tailored during a bespoke desktop design.
- Choose a hybrid-ready inverter (+£405) with no battery on day one when: Someone is home all day using solar live and you want to maximise roof panel count first while scaffolding is up, leaving DC battery terminals ready to plug in a pack later. Read is a home battery worth it?
Solar panels we pair with these batteries
A battery only stores what your roof can generate. We pair our inverter and battery systems with high-efficiency N-type all-black monocrystalline modules:
- AIKO Neostar 2S (465W) & Neostar 3P54 (495W) ↗: N-Type ABC (All Back Contact) cells with zero front gridlines, partial-shading optimisation and high module efficiency (default in our instant design tool).
- Trina Solar Vertex S+ ↗: Dual-glass N-type i-TOPCon modules widely used on domestic and commercial roofs.
- LONGi Hi-MO series ↗: Proven back-contact and TOPCon modules for residential and commercial arrays.
See every 6 to 16 panel price row on our 2026 solar panel price list.
Worked solar + battery prices from our design tool
| System specification | Platform | Indicative cash price |
|---|---|---|
| 10 panels (4.65 kWp) + Fox H-series hybrid + Fox EP6 x1 (~5.2 kWh usable) | Fox ESS H-series + EP6 / EP12 | £6,435 |
| 10 panels (4.65 kWp) + Fox H-series hybrid + Fox EP12 x1 (~10.4 kWh usable) | Fox ESS H-series + EP6 / EP12 | £7,650 |
| 13 panels (6.05 kWp) + Fox H-series hybrid + Fox EP6 x2 (~10.4 kWh usable) | Fox ESS H-series + EP6 / EP12 | £8,280 |
| 8 panels (3.96 kWp, 495W AIKO) + SigenStor EC 3.6 kW + 6.0 kWh battery | Sigenergy SigenStor 5-in-1 | £7,402.50 |
| 8 panels (3.96 kWp, 495W AIKO) + SigenStor EC 3.6 kW + 9.04 kWh battery | Sigenergy SigenStor 5-in-1 | £7,942.50 |
| 16 panels (7.92 kWp, 495W AIKO) + SigenStor EC 8.0 kW + 9.04 kWh battery | Sigenergy SigenStor 5-in-1 | £10,980 |
Every figure is indicative, from the Solar City design tool at solarcityuk.co.uk/design. Scaffolding is extra (around £400-£500 per side) and an on-site survey confirms your final design and price.
Solar battery brand FAQs
Which solar battery and inverter brands does Solar City install?
Solar City installs Fox ESS, Sigenergy and EcoFlow home battery storage and hybrid inverters, paired with Aiko, Trina and LONGi solar panels across Birmingham, Solihull and the West Midlands.
How do Fox ESS EP6 and EP12 compare with Sigenergy SigenStor?
Fox ESS uses a separate wall-mounted H-series hybrid inverter (+£405 in our design tool) paired with modular EP6 (~5.2 kWh usable, +£945) or EP12 (~10.4 kWh usable, +£2,160) LFP packs, whereas Sigenergy SigenStor integrates the energy controller and 6.0 kWh or 9.04 kWh battery modules into a single floor-standing stack (from £7,402.50 for 8x 495W AIKO panels + 6.0 kWh battery in our design tool). Every figure is indicative, from the Solar City design tool at solarcityuk.co.uk/design. Scaffolding is extra (around £400-£500 per side) and an on-site survey confirms your final design and price.
What battery cell chemistry do Fox ESS, Sigenergy and EcoFlow use?
All three residential battery lines we install - Fox ESS EP-series, Sigenergy SigenStor and EcoFlow PowerOcean - use lithium iron phosphate (LiFePO4 / LFP) cell chemistry, chosen for thermal stability, Cobalt-free cathodes and high cycle life.
Do these solar batteries provide backup power during a grid power cut?
Standard grid-tied hybrid installations shut down during a power cut to comply with DNO anti-islanding safety rules (G98/G99), unless an Emergency Power Supply (EPS) socket, dedicated backup circuit or automatic gateway (such as the Sigenergy Gateway or Fox ESS EPS box) is specified and wired during installation.
What manufacturer warranties apply to the batteries and panels you install?
Manufacturer product and performance warranties vary by model and registration (typically 10 years on residential LFP batteries subject to manufacturer cycle/throughput terms, 10 years on registered Fox ESS and Sigenergy inverters, and 15 to 25 years product / 30 years linear power warranty on AIKO, Trina and LONGi N-type modules), alongside Solar City’s 5-year workmanship warranty and IWA insurance-backed cover.
Compare Fox ESS and Sigenergy on your roof
Switch between Fox ESS and Sigenergy live in our instant design tool, or call our Tyseley engineers on 0121 707 9991.