Tesla · Home battery model
Powerwall 3 Expansion
Powerwall 3 Expansion is a 13.5 kWh battery-only extension for Tesla Powerwall 3, with up to three Expansion units supported behind one Powerwall 3.
Specifications
| Specification | Value |
|---|---|
| Nominal energy (kWh) | 13.5 |
| Compatible with | Powerwall 3 only |
| Maximum expansion units per Powerwall 3 | 3 |
| Maximum additional energy (kWh) | 40.5 |
| Inverter included | no |
| Operating temperature (°C) | -20 to 50 |
| Ingress-protection rating | IP67 |
| Dimensions (mm) | 1105 x 609 x 168 |
| Unit weight (kg) | 110 |
Powerwall 3 Expansion is an additional battery enclosure for a Tesla Powerwall 3 system. It provides 13.5 kWh of nominal energy but does not contain another grid or solar inverter. It cannot operate as a standalone home battery and Tesla specifies compatibility with Powerwall 3 only.
Capacity and configuration
Up to three Expansion units can connect behind one Powerwall 3, adding a maximum of 40.5 kWh to that unit’s own 13.5 kWh. In Tesla’s maximum documented multi-unit arrangement, a system can have four Powerwall 3 units and three Expansion units, giving seven battery enclosures and 94.5 kWh of nominal energy.
The Expansion units connect in parallel using a dedicated harness. Cable options in the UK datasheet are 0.5 m, 2 m and 4 m. Expansion batteries are not field-serviceable. The additional energy increases how long the system can sustain a given load, but it does not by itself increase the Powerwall 3 inverter’s AC output.
Physical installation
An Expansion measures 1,105 by 609 by 168 mm with its glass cover fitted. The battery enclosure weighs 110 kg without the cover and mounting bracket, or 118.5 kg as a complete wall-mounted unit. It can be mounted on a wall or floor. Up to three can be stacked behind a floor-mounted Powerwall 3; the stacking arrangement is not a wall-mount option.
The unit is rated IP67 and for indoor or outdoor operation from -20°C to 50°C. Tesla notes that performance may reduce above 40°C. The location and supporting structure therefore have to suit both the environmental rating and the concentrated weight.
Compatibility and warranty
Powerwall 3 controls and reports the added storage through the same Tesla app and system gateway or remote meter. Tesla’s European Powerwall warranty, effective 3 December 2025, explicitly includes Powerwall 3 Expansion part number 1807000-xx-x. It provides a ten-year warranty and makes registration and continued internet connectivity conditions of the full term. The Expansion has to be installed and registered as part of a compatible system, and the warranty document supplied for that installation remains authoritative.
Related entries
Brand
Reference type
Home battery model
Last reviewed
23 Jul 2026
Current status
Current in the manufacturer's UK range.