Tesla Powerwall 3
The Powerwall 3 figures below distinguish on-grid AC output, AC charging and the solar-to-battery-to-home efficiency. Those are different paths through the system.
Research from manufacturer documents, not a hands-on test. Values and missing details are kept separate below.
- Solar / AC charging
- Powerwall 3
- Household AC
What matters on your quote
Use the installed export/import limits and the actual configured output on your quote, rather than assuming the headline output is available at every property.
- The full warranty depends on internet connectivity and the type of use.
- Backup requires the specified islanding device and installation; it is not established by the battery capacity alone.
At a glance
| Usable capacity | 13.5 kWh (AC), the minimum guaranteed at beginning of life |
|---|---|
| Continuous / rated power (original units and basis) | Up to 11.04 kW on-grid, depending on local conditions |
| Charging power | AC configurable up to 5 kW (Powerwall 3 on its own) |
| Round-trip efficiency | 89% solar to battery to home/grid (includes the inverter) |
| Warranty (years) | 10 years, if the battery stays reliably connected to the internet |
| Warranty throughput / cycles | UK: unlimited cycles for solar self-consumption, time-based control and backup; 37.8 MWh of throughput for any other use |
| Capacity at end of warranty | 80% of 13.5 kWh at 10 years (UK) |
| Coupling | Built-in solar inverter with 3 solar inputs (MPPTs) |
| Expandable to | Up to 4 units |
| Backup power | Only with the Backup Gateway 2, Tesla’s supported islanding device |
Not in the documents we checked so far: peak power, UK list price.
Ask the installer before you sign
- Is the usable capacity on the quote the figure above, or a nominal one?
- Can it charge fast enough to fill in your cheap window? Charging power × hours of the window is the most it can take in.
- Is any equipment needed for backup in a power cut included in the price?
- Does it work alongside your current solar inverter, or replace it?
- Which warranty conditions apply in the UK, and what do you have to do to keep them?
Will it pay back for you?
Opens the calculator with this battery’s usable capacity and charging power filled in. Add your own installed price and tariff. If the datasheet does not state a round-trip efficiency, use your installer’s figure.
Sources and quotes (10)
Usable capacity: 13.5 kWh (AC), the minimum guaranteed at beginning of life
“13.5 kWh AC is minimum guaranteed at beginning of life, 25°C, and 5 kW charge/discharge power”Source: energylibrary.tesla.com (PDF, page 2), read 22 October 2026
Continuous / rated power (original units and basis): Up to 11.04 kW on-grid, depending on local conditions
“Up to 11.04 kW, depending on local conditions”Source: tesla.com, read 21 October 2026
Charging power: AC configurable up to 5 kW (Powerwall 3 on its own)
“AC Configurable up to 5 kW”Source: energylibrary.tesla.com (PDF, page 2), read 26 October 2026
Round-trip efficiency: 89% solar to battery to home/grid (includes the inverter)
“89%”Source: energylibrary.tesla.com (PDF, page 2), read 26 October 2026
Warranty (years): 10 years, if the battery stays reliably connected to the internet
“Powerwall 3 must be reliably connected to the internet to secure the full 10-year warranty.”Source: energylibrary.tesla.com (PDF, page 2), read 26 October 2026
Warranty throughput / cycles: UK: unlimited cycles for solar self-consumption, time-based control and backup; 37.8 MWh of throughput for any other use
“Unlimited cycles”Source: energylibrary.tesla.com (PDF, page 1), read 26 October 2026
Capacity at end of warranty: 80% of 13.5 kWh at 10 years (UK)
“80% at 10 years following initial installation date”Source: energylibrary.tesla.com (PDF, page 1), read 26 October 2026
Coupling: Built-in solar inverter with 3 solar inputs (MPPTs)
“MPPTs 3”Source: energylibrary.tesla.com (PDF, page 2), read 26 October 2026
Backup power: Only with the Backup Gateway 2, Tesla’s supported islanding device
“Supported Islanding Device Backup Gateway 2”Source: energylibrary.tesla.com (PDF, page 2), read 26 October 2026