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Tesla Powerwall 3 vs SigenStor vs Fox Evo compared

Short answer

All three are LFP-based hybrid systems with solar inputs. Powerwall 3 gives 13.5 kWh and up to 11.04 kW single-phase. SigenStor stacks 5.84 or 8.76 kWh modules on 3-12 kW single-phase or 5-30 kW three-phase controllers. Fox Evo packs 9.73 kWh with 5-10 kW. Warranties differ: 80%, 60% and 70% retained (checked 24 Sept 2026).

Last checked 24 September 2026 · 18 sources

What should I know before deciding?

Powerwall 3: 13.5 kWh, 3 MPPT, 5 kW charge (8 kW with Expansions), up to 11.04 kW discharge, app only, whole-home backup via Backup Gateway 2, single-phase in UK (2025 datasheet). SigenStor: 1-6 modules per controller (max ~52.6 kWh), 3.0 or 4.6 kW per module, LED status only, heating below 0 C, Sigen Gateway for whole-home and three-phase backup (datasheet, manual). Fox Evo 10: 10.24 kWh nominal / 9.73 usable, 3 MPPT, EPS switch <4 ms, LCD screen, up to 3 units, gen 2 expansion port announced for autumn 2026 (datasheet v1.1; fox-ess.uk). Warranties: Tesla 10 yrs 80% unlimited cycles for self-use/TOU/backup; Sigen 10 yrs 60% or 20.44/30.66 MWh; Fox Evo 12 yrs 70% or 47.88 MWh. Price per usable kWh depends on installer quote; no manufacturer price list verified.

Which batteries can be expanded later, and by how much?

Modular stacks are easiest to grow: SigenStor takes up to six modules per controller, Huawei LUNA S1 three per group, Duracell Dura5 up to 32 in parallel. Powerwall 3 adds up to three DC Expansions per system (datasheet max 94.5 kWh). Fox Evo gen 1 expands only by adding whole units, up to three (checked 24 Sept 2026).

SigenStor: 1-6 BAT modules per EC controller; BAT 6.0 and 10.0 can be mixed thanks to built-in optimiser (datasheet). Powerwall 3: up to 4 PW3 units and up to 3 Expansion units, max 7 units / 94.5 kWh; Expansions are DC, PW3-only and not field serviceable (2025 datasheet). Fox EVO: parallel up to 3 complete units (10-30 kWh); gen 2 expansion port for two extra EVO units due autumn 2026.

How fast can each battery charge and discharge?

Power, not just kWh, decides whether a battery covers a cooker plus heat pump or fills in a short cheap slot. Powerwall 3 charges at 5 kW (8 kW with Expansions) and discharges up to 11.04 kW. Each SigenStor module handles 3 or 4.6 kW. Huawei LUNA S1 manages 3.5 kW per module (checked 24 Sept 2026).

Powerwall 3: charge 5 kW, 8 kW with 1-3 Expansions; discharge configurable to 11.04 kW. SigenStor BAT 6.0 3.0 kW / BAT 10.0 4.6 kW continuous per module, capped by the EC controller rating. Fox EVO: inverter 5-10 kW; battery charge power not separately stated.

Which home batteries give whole-home backup in a power cut?

Whole-home backup needs a gateway or backup box that isolates the house from the grid: Tesla Backup Gateway 2, Sigen Gateway HomePro, Fox EPS Box SP or the Giv-Gateway. Many hybrids only offer an EPS output for a few circuits, and some, like the UK Enphase IQ Battery 5P, offer no backup (checked 24 Sept 2026).

Whole-home via gateway: Tesla PW3 + Backup Gateway 2 (100 A single-phase); SigenStor + Sigen Gateway (SP 12/22 kW, TP 30 kW); Fox EVO/H1-G2/KH + EPS Box SP (launched 18 July 2025); GivEnergy AIO + Giv-Gateway (100 A, 20 ms). EPS circuits only: GivEnergy Gen 3 hybrid (3.6 kW/16 A, 10 ms), Solis S6 (<10 ms), SolaX X1 G4 (<10 ms), Dura-i (10-20 ms), EcoFlow PowerOcean backup port, AlphaESS SMILE-G3 backup port. Socket/lighting circuit only: myenergi libbi optional blackout backup.

Which batteries work on a three-phase supply and back up all three phases?

In the UK, Powerwall 3 is single-phase only, although Backup Gateway 2 accepts three-phase feed-in. SigenStor offers 5-30 kW three-phase controllers with a three-phase gateway. Victron MultiPlus-II can be built into three-phase sets, and Huawei, SolaX and Fox also sell three-phase hybrids (checked 24 Sept 2026).

Tesla: PW3 grid type single phase 230 V; Backup Gateway 2 feed-in single or three phase; backup of one phase only. SigenStor EC TP 5.0-30.0 kW; Sigen Gateway HomePro TP 30 kW for three-phase backup. Victron MultiPlus-II: three units per three-phase set, up to 6 sets in parallel.

What to do next

Use your own half-hourly electricity data where possible. Compare usable kWh, kW, tariff rules and warranty terms before buying.

Sources

Last checked: 24 September 2026