Sigenergy vs Tesla Powerwall 3: SigenStor Compared
Integrated 5-in-1 electrification platform vs the best-known premium battery. The SigenStor bundles inverter, stackable storage, EV DC charger and AI EMS; Powerwall 3 is a polished single-unit with whole-home backup.
Both are premium. The SigenStor wins where you want one integrated system doing solar + battery + EV + management, especially with three-phase or a large stack up to ~54 kWh. The Tesla Powerwall 3 wins on brand recognition, whole-home EPS and single-unit simplicity. For a whole-home electrification project the SigenStor is the more complete platform; for a straightforward premium battery with the Tesla app, Powerwall 3 is hard to fault.
Side-by-side spec compare
| Spec | Sigenergy SigenStor | Tesla Powerwall 3 | Winner |
|---|---|---|---|
| System architecture | 5-in-1 integrated tower | Single-unit battery + inverter | A |
| Usable capacity | 6.02–~54 kWh stackable LFP | 13.5 kWh (stack units) | A |
| Battery chemistry | LFP (LiFePO4) | NMC | A |
| Continuous power | Up to ~25 kW (three-phase) | 11.04 kW | A |
| Three-phase variant | Yes (up to 30 kW) | Single-phase domestic | A |
| EV charger built-in | Optional integrated DC charger | No | A |
| AI energy management | Sigen.AI native EMS | Tesla app scheduling | A |
| EPS backup | Sub-ms, scope by design | Whole-home, 60 ms | B |
| IP rating | IP66 indoor/outdoor | Wall-mount, weather-rated | = |
| Brand recognition | Newer to UK | Market-leading | B |
| Warranty | ~10 yrs | 10 yrs | = |
Which one is right for you?
Single-cabinet integration of solar + battery + EV + AI EMS is uniquely SigenStor.
Up to ~25 kW three-phase and ~54 kWh storage outreach a single Powerwall.
The SigenStor uses LFP; Powerwall 3 uses NMC.
Powerwall 3 whole-home EPS is genuinely category-leading.
Tesla is the most recognised battery brand on the market.
Published specifications, side by side
| Specification | Sigenergy SigenStor | Tesla Powerwall 3 |
|---|---|---|
| Battery capacity | Modules of 6.02 or 9.04 kWh (LiFePO4); 1–6 modules per controller, so roughly 6–54 kWh | 13.5 kWh per unit, fixed |
| Scaling | Add modules to the tower, then run multiple SigenStors in parallel for commercial sites | Up to 4 units |
| Power output | Inverter AC output 3–12 kW single-phase, 5–30 kW three-phase | Up to 11.04 kW on-grid and on backup, depending on local conditions |
| Efficiency | Max inverter efficiency 97.6–98.0% single-phase, 98.1–98.4% three-phase | Solar-to-grid efficiency 97.5% |
| Solar inputs | 2–4 MPPTs, max 16 A per MPPT | 3 solar inputs with maximum power point trackers |
| Module power | 3,000 W charge / 4,600 W discharge per battery module | Not published separately — the unit is one sealed product |
| EV charging | Optional integrated 25 kW bi-directional DC module, V2H and V2G ready | None integrated — an EV charger is a separate product |
| Depth of discharge | 100% usable energy capacity | Not published on the UK page |
| Siting | IP66, floor-standing or wall-mounted, natural convection or smart air cooling | 1,105 × 609 × 193 mm, 130 kg, flood resistant to 0.6 m |
| Operating temperature | Not published on the specifications page | −20°C to 50°C |
| Warranty | Not published on the specifications page — your quote states it | 10 years |
Every figure below is the manufacturer's own published specification, read on 25 September 2026 — Sigenergy's SigenStor specifications page and Tesla's UK Powerwall page. Where a manufacturer does not publish a figure we say so rather than fill the gap.
Where the difference actually shows up in a Scottish home
On paper these are both premium systems with a ten-year-class warranty and an integrated inverter. Four differences decide which one we specify, and none of them is brand.
Three-phase supplies. A fair number of Central Belt properties — converted farm steadings, larger detached homes, anything with a workshop or a commercial element — run three-phase. Sigenergy publishes a three-phase controller from 5 to 30 kW. Tesla's UK Powerwall page lists a single specification, up to 11.04 kW. If your supply is three-phase and you want to use it, that narrows the choice quickly.
An EV in the plan. The SigenStor can take an integrated 25 kW bi-directional DC charging module, and Sigenergy lists it as V2H and V2G ready. With a Powerwall, EV charging is a separate wall unit and a separate circuit. If a car is coming in the next few years, that is a second install visit you can avoid — or not, if you already have a charger you like.
How you grow. The SigenStor grows inside the tower: add a 6.02 or 9.04 kWh module, up to six per controller. A Powerwall grows in 13.5 kWh steps, up to four units. That matters if your honest starting size is 6–9 kWh: with Tesla the smallest step is the whole 13.5 kWh.
Where it goes. The Powerwall is a single 130 kg wall-mounted unit, flood resistant to 0.6 m. The SigenStor is a stackable tower rated IP66 that can stand on the floor or hang on a wall. In a tenement close, a narrow utility room or a garage with limited wall run, that decides it more often than any specification does.
What each costs to install
Our typical installed price for a Tesla Powerwall 3 is around £10,500, and SigenStor systems run from about £8,000 for a small tower to £35,000 for a large three-phase configuration with the EV DC module — because the SigenStor is configurable, its price moves with the inverter size, how many battery modules you fit and whether the EV module goes in.
Both qualify for 0% VAT on installation in a home until 31 March 2027 under HMRC VAT Notice 708/6, including a battery retrofitted to existing solar. After that the rate is due to revert to 5%.
Compare quotes on the same basis: usable kWh, the inverter's kW rating, whether the price includes the EPS or backup wiring, and who holds the workmanship warranty. A cheaper quote that leaves backup wiring out is not the same job.
What neither manufacturer will tell you
Tesla asks you to request a quote from a Tesla Certified Installer, and the Powerwall warranty is written around the product being bought and installed through that route — so check your installer's status before you sign, whoever you use.
Sigenergy publishes an installer map of certified installers for the same reason. Certification is worth checking on the manufacturer's own site rather than taking a badge on a quote at face value.
And the honest answer to “which is better” is that both will do the job in most homes. The system that fails to earn its keep is usually the one sized to a sales number rather than to a load profile — which is why we size storage from your own half-hourly data first. Our solar battery size calculator runs that method in a couple of minutes.
Questions people ask
Is the SigenStor better than a Tesla Powerwall 3?
Neither is better in the abstract. The SigenStor wins where you have three-phase, want EV DC charging in the same tower, or need to start smaller than 13.5 kWh and grow in 6–9 kWh steps. The Powerwall 3 wins on simplicity — one sealed 13.5 kWh unit, one app, a ten-year warranty and the largest installed base in the UK.
How much storage can each one hold?
Sigenergy lists battery modules of 6.02 kWh and 9.04 kWh with one to six modules per controller, so roughly 6 to 54 kWh in a single tower, and multiple towers in parallel for commercial sites. Tesla lists 13.5 kWh per Powerwall 3 and scaling up to four units.
Which has more power output?
Tesla publishes up to 11.04 kW on-grid and on backup for Powerwall 3. Sigenergy publishes an inverter AC output of 3–12 kW single-phase and 5–30 kW three-phase, so a three-phase SigenStor can be specified well above a single Powerwall — but a single-phase SigenStor and a Powerwall are in the same class.
Do both work with Octopus Flux?
Both are time-of-use capable and are commonly run on tariffs like Octopus Flux, which pays a higher export rate from 16:00 to 19:00. What matters in practice is that the battery can be told when to charge and discharge, and that the installer sets those windows up at commissioning rather than leaving the default.
Can I add capacity later?
With the SigenStor you add a module to the existing tower, up to six per controller. With the Powerwall you add another unit, in 13.5 kWh steps, up to four. Ask for the expansion route in writing before you buy — it is the difference between a half-day visit and a second full install.
The figures behind this page
| Figure | Value | Source |
|---|---|---|
| SigenStor battery modules and stack limit | 6.02 / 9.04 kWh LiFePO4; 1–6 modules per controller | sigenergy.com SigenStor specifications — 25 Sep 2026 |
| SigenStor inverter output and efficiency | 3–12 kW single-phase, 5–30 kW three-phase; 97.6–98.4% max | sigenergy.com SigenStor specifications — 25 Sep 2026 |
| SigenStor EV DC charging | 25 kW bi-directional, V2H and V2G ready | sigenergy.com SigenStor product page — 25 Sep 2026 |
| Powerwall 3 capacity, power and warranty | 13.5 kWh; up to 11.04 kW on-grid and backup; 10 years; up to 4 units | tesla.com/en_gb/powerwall — 25 Sep 2026 |
| Powerwall 3 size, weight and efficiency | 1,105 × 609 × 193 mm, 130 kg; solar-to-grid 97.5% | tesla.com/en_gb/powerwall — 25 Sep 2026 |
| VAT on home battery installation | 0% until 31 March 2027, then 5% | HMRC VAT Notice 708/6 |
| Installed price bands | Powerwall 3 about £10,500; SigenStor about £8,000–£35,000 by configuration | Ecoaim 2026 installed prices |
Page updated 2026-09-25.
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