Tesla Powerwall 3 vs Sigenergy SigenStor
Tesla Powerwall 3 stores 13.5 kWh per unit, expanding to 94.5 kWh. Sigenergy SigenStor stores 5.2–7.8 kWh per unit, expanding to 46.8 kWh. Across the setups we list, continuous power is 11.04 kW for the Powerwall 3 and 4–6 kW for the SigenStor. Warranty: 10 years vs 10 years. Intelligent Octopus Flux: Powerwall 3 is “On Octopus's integration list”; SigenStor is “Not on Octopus's list”.
Figures from manufacturer documents, last checked 26 Sept 2026. We don't rank products or take payment for results.
How they're built
Tesla Powerwall 3
All-in-one: battery with built-in hybrid solar inverter (solar connects on the DC side).
Backup: Backup Gateway 2 (required for backup installs).
Sigenergy SigenStor
Modular: Energy Controller (hybrid inverter, solar on DC side) plus stacked battery modules.
Backup: Sigen Energy Gateway.
Side by side
| Specification | Tesla Powerwall 3 | Sigenergy SigenStor |
|---|---|---|
| Usable capacity (per unit) | 13.5 kWhAC, minimum at beginning of life, 25°CTesla datasheet, p.2 & p.4 | 5.2–7.8 kWhPer module: BAT 5.0 = 5.2 kWh, BAT 8.0 = 7.8 kWhSigenergy datasheet, Specification table |
| Battery chemistry | Not documented | LFP (LiFePO₄)Sigenergy datasheet, Specification table |
| Maximum usable storage (expanded) | 94.5 kWhMultiple Powerwall 3 units and/or ExpansionsTesla datasheet, p.1 | 46.8 kWhcalculatedPer controllerSigenergy datasheet |
| How it expands | Up to 4 Powerwall 3 units and up to 3 Expansion units (max 7 units)Tesla datasheet, p.2 | 1–6 battery modules per controllerSigenergy datasheet, p.2, Battery connection |
| Continuous power (per unit) | 11.04 kWInstaller-configurable: 3.68, 5, 6, 7, 8, 9, 10 or 11.04 kWTesla datasheet, p.2, Nominal AC Output Power at 230 V | 3–6 kWSingle-phase controllers 3.0–6.0 kW; also limited by battery modules (2.5 kW per BAT 5.0, 4 kW per BAT 8.0)Sigenergy datasheet, p.2, Single-phase controller, nominal output power |
| Peak power | Not documented | 4.5–9 kWSingle-phase backup peak for 10 seconds, 4.5–9 kW by controllerSigenergy datasheet, p.2, AC output (backup), peak 10 s |
| Round-trip efficiency | 89%Solar → battery → home/grid, typical use caseTesla datasheet, p.2, footnotes 1 & 3 | Not documented |
| Architecture | All-in-one: battery with built-in hybrid solar inverter (solar connects on the DC side)Tesla datasheet, p.1 & p.3 solar specifications | Modular: Energy Controller (hybrid inverter, solar on DC side) plus stacked battery modulesSigenergy datasheet, p.1–2 |
| Max solar input | 20 kWMaximum solar STC inputTesla datasheet, p.3 | 6–12 kWSingle-phase controllers 3.0–6.0 SPSigenergy datasheet, p.2, DC input |
| Backup switchover time | Not documented | 0 msNeeds the Sigen Energy Gateway; load-side disruptionSigenergy datasheet, p.2, footnote 1 |
| Backup needs | Backup Gateway 2 (required for backup installs)Tesla datasheet, p.2 & p.5 | Sigen Energy GatewaySigenergy datasheet, p.2, footnote 1 |
| Indoor / outdoor | Indoor and outdoor ratedTesla datasheet, p.3 | Not documented |
| Dimensions | 1105 × 609 × 193H × W × D as listedTesla datasheet, p.3 | 767 × 270 × 260 (per module)W × H × DSigenergy datasheet |
| Weight | 130 kgTesla datasheet, p.3 | 55–70 kgPer module: 55 kg (BAT 5.0), 70 kg (BAT 8.0)Sigenergy datasheet |
| Warranty (UK) | 10 yearsMust be reliably connected to the internet for the full 10 yearsTesla datasheet, p.2, footnote 6 | 10 yearsBattery and Energy Controller; installed on or after 1 June 2023Sigenergy warranty, p.1 |
| Capacity guaranteed at end of warranty | 80%80% of 13.5 kWh at 10 yearsTesla warranty, p.1, retention table for Austria, Belgium, France, Germany, Ireland, Luxembourg, Netherlands, Switzerland or the UK | 70%70% of usable energySigenergy warranty, p.1 |
| Warranty conditions | Unlimited cycles for solar self-consumption, time-based control and backup; 37.8 MWh throughput limit for other uses. Minimum 4-year cover if not kept online.Tesla warranty, p.1 & p.3 | Must stay connected to the internet for the full 10 years; 5 years minimum otherwise.Sigenergy warranty, p.2 |
How long each runs your home in a power cut
Every setup we list for both, from a full battery with no solar. Appliance figures are typical estimates; use the calculator below with your own.
| Setup | Usable | Continuous | Essentials (fridge-freezer, lights, Wi-Fi, TV, charging) | Essentials + air-source heat pump (winter) |
|---|---|---|---|---|
| Tesla Powerwall 3 | 13.5 kWh | 11.04 kW | 3 days 10 hours | 7.7 hours |
| Tesla Powerwall 3 + 1 Expansion | 27 kWh | 11.04 kW | 6 days 20 hours | 15.5 hours |
| Tesla Powerwall 3 + 2 Expansions | 40.5 kWh | 11.04 kW | 10 days 7 hours | 23.2 hours |
| Tesla Powerwall 3 + 3 Expansions | 54 kWh | 11.04 kW | 13 days 17 hours | 31 hours |
| Sigenergy SigenStor · 6.0 SP controller + 1 × BAT 8.0 | 7.8 kWh | 4 kW | 47.5 hours | 4.5 hours |
| Sigenergy SigenStor · 6.0 SP controller + 2 × BAT 8.0 | 15.6 kWh | 6 kW | 3 days 23 hours | 8.9 hours |
| Sigenergy SigenStor · 6.0 SP controller + 3 × BAT 8.0 | 23.4 kWh | 6 kW | 5 days 23 hours | 13.4 hours |
Try your own appliances
Average draw 156 W from 12.83 kWh available.
Everything on at once: 415 W — within the 11.04 kW limit
- Starts from a full battery with 0% held back as reserve.
- 5% extra allowed for wiring and standby losses on top of the manufacturer's usable figure.
- Appliance figures are typical averages; your own may differ. Enter your own wattage for the most accurate result.
- Assumes no solar recharging during the outage.
- Powerwall 3: Battery chemistry is not stated in the UK datasheet.
- Powerwall 3: A peak power figure in kW is not stated in the UK datasheet; it lists motor-start capability of 185 A (locked rotor amps).
- Powerwall 3: Continuous output is set by the installer (3.68–11.04 kW). Ask what yours will be set to.
- SigenStor: Warranty figures are from Sigenergy's Europe warranty; confirm UK coverage with your installer.
- SigenStor: Round-trip efficiency is not stated as a single figure in the datasheets we hold.
- SigenStor: Larger single-phase controllers may exist in the UK; this page covers the 3.0–6.0 SP range in the datasheet we hold.
Questions people ask
Which stores more, Tesla Powerwall 3 or Sigenergy SigenStor?
Tesla Powerwall 3 has the higher stated maximum. Tesla Powerwall 3: up to 94.5 kWh (multiple Powerwall 3 units and/or Expansions). Sigenergy SigenStor: up to 46.8 kWh (per controller). Per unit, Tesla Powerwall 3 stores 13.5 kWh and Sigenergy SigenStor stores 5.2–7.8 kWh.
Which can run more appliances at once?
Across the setups we list, Tesla Powerwall 3 delivers 11.04 kW continuously and Sigenergy SigenStor delivers 4–6 kW. These are the maximums for each setup; installers can set some systems lower. Continuous power limits how many appliances can run at the same time; capacity decides how long they run.
Which has the better warranty?
Tesla Powerwall 3: 10 years, 80% capacity guaranteed at the end. Sigenergy SigenStor: 10 years, 70% capacity guaranteed at the end. Conditions differ, so check the warranty rows in the table above.
Do Tesla Powerwall 3 and Sigenergy SigenStor work with Intelligent Octopus Flux?
Tesla Powerwall 3: On Octopus's integration list. Sigenergy SigenStor: Not on Octopus's list. Octopus lists the battery brands it can control in its Intelligent Flux FAQ; see our Intelligent Octopus Flux page for details.
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Sources
- Powerwall 3 Datasheet (UK) — Tesla, 2026. Retrieved 26 Sept 2026.
- Powerwall Limited Warranty (Europe incl. UK) — Tesla, Rev. 1.16, effective 3 Dec 2025. Retrieved 26 Sept 2026.
- Sigen Battery 5.0 / 8.0 kWh datasheet — Sigenergy. Retrieved 26 Sept 2026.
- Datasheet – SigenStor Home (Energy Controller) — Sigenergy. Retrieved 26 Sept 2026.
- Factory Limited Warranty for SigenStor (For Europe) — Sigenergy. Retrieved 26 Sept 2026.
- Intelligent Octopus Flux: Frequently Asked Questions — Octopus Energy. Retrieved 26 Sept 2026.
Spotted an error? See how we check data. Always confirm your final design with an MCS-certified installer.