With home battery storage becoming an essential part of energy independence, the Tesla Powerwall 3 and Sigenergy SigenStor stand out as two of the best options in the UK. Both offer solar integration, backup power, and scalability, but which one is right for your home?
This detailed comparison breaks down the key differences between these two advanced battery systems to help you make an informed choice.
| Tesla Powerwall 3 | Sigenergy SigenStor | |
| Usable Capacity | 13.5 kWh | 5.2 kWh (5 kWh module), 7.8 kWh (8 kWh module) |
| Maximum Storage Capacity | 216 kWh | 48 kWh per stack, up to 240 kWh (single-phase), 2.4 MWh (three-phase) |
| Battery Chemistry | Lithium Ferro Phosphate (LFP) | Lithium Ferro Phosphate (LFP) |
| Charge Rate | 5 kW standard | 2.5 kW (5 kWh module), 4 kW (8 kWh module) |
| Maximum Charge Rate | 8 kW | 12 kW (inverter dependent) |
| Peak Output Power | 170% of rated capacity | 200% of rated capacity |
| Integrated Inverter | Yes (11.04 kW hybrid inverter) | Yes, various inverter options |
| Adjustable Inverter Settings | Yes (3.68 kW - 10 kW) | No (requires new inverter for upgrades) |
| Maximum Solar Input | Up to 20 kW | Up to 30 kW |
| Backup Power Support | Yes (Gateway 2 included) | Optional Backup Gateway |
| EV Charging Support | No integrated EVCP | Yes (V2H/V2G-ready) |
| Warranty (Battery) | 10 years (unlimited cycles) | 10 years (70% capacity retention) |
| Warranty (Extended) | Not available | 15 years (60% capacity retention, additional cost) |
| Temperature Operating Range | -20 to 50°C | -20 to 60°C |
| Weight | 130 kg | 18 kg - 456 kg (stack configuration dependent) |
| Dimensions | H 1150 mm x W 753 mm x D 147 mm | H 370 mm - 1990 mm x W 700 mm x D 260 mm (stack configuration dependent) |
| IP Rating | IP67 | IP66 |
Tesla vs Sigenergy: Company Background
- Tesla has been a market leader in home battery storage since launching the Powerwall 1 in 2015. With the Powerwall 3, Tesla offers a fully integrated inverter and improved performance, ensuring seamless solar integration.
- Sigenergy, founded in 2022, is a new but fast-growing player. Led by Tony Zuu, former president of Huawei’s Fusion Solar division, the company has already achieved €100 million in sales.
Battery Capacity & Scalability
A home battery’s storage capacity and expansion potential are crucial for meeting long-term energy needs.
Tesla Powerwall 3
- 13.5 kWh usable capacity (100% depth of discharge)
- Expandable to 54 kWh per stack (three expansion units per Powerwall)
- Maximum 216 kWh storage per home (four stacks per single-phase supply)
- Integrated hybrid inverter eliminates the need for an external inverter
Sigenergy SigenStor
- Modular design with 5 kWh and 8 kWh battery modules
- Expandable to 48 kWh per stack (6x 8 kWhmodules)
- Maximum 240 kWh storage per home (five stacks per phase)
- Greater flexibility to mix battery module sizes
Tesla’s system is easier to scale, while Sigenergy offers more customisation with its modular approach.
Battery Chemistry & Lifespan
Both systems use Lithium Iron Phosphate (LFP) battery technology, which offers:
- Longer lifespan than traditional lithium-ion batteries
- Enhanced safety with a lower risk of overheating
- Improved sustainability compared to older chemistries
Tesla previously used Nickel Manganese Cobalt (NMC) but now utilises LFP for better durability—aligning with Sigenergy.
Charge & Discharge Rates
How fast a battery charges and discharges affects how effectively you can use stored energy.
Tesla Powerwall 3
- 5 kW standard charge rate
- 8 kW charge rate with expansion pack
- Max charge rate remains 8 kW, even with multiple packs
- 54 kWh system charges in ~6h 45m
Sigenergy SigenStor
- Each module charges at half its rated capacity
- 5 kWh module → 2.5 kW charge rate
- 8 kWh module → 4 kW charge rate
- Max charge rate of 12 kW for single-phase homes (inverter-dependent)
Tesla has a fixed charge rate, making it ideal for predictable energy storage, while Sigenergy offers higher charge rates with multiple modules.
Built-in Hybrid Inverter: Key Differences
Tesla Powerwall 3
- 11.04 kW hybrid inverter included
- Software adjustable settings (3.68 kW - 10 kW) for dynamic DNO compliance
- Supports up to 17 kW inverter capacity oversizing
Sigenergy SigenStor
- Integrated inverter within the Energy Controller unit
- Single-phase options: 3 kW - 12 kW
- Three-phase options: 5 kW - 30 kW
- Can be oversized to 200% of inverter capacity
- Requires a new inverter for capacity upgrades
Tesla’s inverter is software-adjustable, while Sigenergy requires a physical inverter upgrade for higher output.
Solar Integration & Smart Features
Tesla Powerwall 3
- Built-in solar inverter with three MPPTs
- Supports up to 20 kW DC solar input
- Storm Watch pre-charges battery for severe weather
Sigenergy SigenStor
- MPPT inputs vary by inverter size (see table)
- V2H & V2G-ready DC EV charger (12 kW or 25 kW)
If EV charging is a priority, Sigenergy is the better choice with Vehicle-to-Home (V2H) and Vehicle-to-Grid (V2G) capability.
Backup Power & Grid Independence
Tesla Powerwall 3
- Includes Gateway 2 for full home backup
- Supports AC-coupled solar in power outages
- Does not support generator input or critical load control
Sigenergy SigenStor
- Backup Gateway is optional
- Supports both single-phase & three-phase backup
- Allows generator integration & smart load control
Tesla offers ready-to-use backup power, while Sigenergy is more customisable.
Warranty & Long-Term Value
Tesla Powerwall 3
- 10-year warranty with unlimited cycles
- Covers all components, including expansion packs & Gateway 2
Sigenergy SigenStor
- 10-year warranty with 70% capacity retention
- Extended 15-year warranty available
- Gateway warranty: 2 years | DC charger warranty: 3 years
Tesla’s unlimited cycle warranty provides greater peace of mind, though Sigenergy’s extended warranty option is very handy.
Price & Cost-Effectiveness
Tesla Powerwall 3
Tesla Powerwall 3 - starting at £7750.
Tesla Powerwall 3 DC Expansion Pack when installed with Powerwall 3, saving labour cost - starting at £5000.
Sigenergy SigenStor
| Inverter Rating (kW) | Battery Modules | Total Battery Capacity | Estimated Price |
| 3 | 1x 5 kWh | 5 kWh | £6,100 |
| 6 | 8 kWh + 5 kWh | 13 kWh | £8150 |
| 12 | 6x 8 kWh | 48 kWh | £8150 |
*With power cut protection
To upgrade your unit with an 5 kWh module, it should cost around £3100.
To upgrade your unit with an 8 kWh module, it should cost around £3500.
To upgrade your unit with the EV DC Charger module, it should cost between £3,500 - £4,000.
- Tesla Powerwall 3 is more cost-effective in standard setups.
- Sigenergy becomes more cost-efficient for large-scale storage, thanks to its modular expansion.
Which Home Battery Should You Choose?
Choose Tesla Powerwall 3 if you want:
- A proven, all-in-one system with seamless solar integration
- Unlimited cycle warranty for long-term peace of mind
- A simple, high-performance solution with full backup power
Choose Sigenergy SigenStor if you want:
- Modular storage for flexible expansion
- Future-proofed EV charging with V2H/V2G capabilities
- More control over inverter size & power distribution
Need Expert Advice?
Choosing between Tesla Powerwall 3 vs Sigenergy SigenStor depends on your home’s energy needs and future plans.
If you’re unsure which system is right for you, contact us today for a free consultation and expert advice.
