Tesla Powerwall 3 with Backup Gateway 2 Installation Manual AU v1.11 v21Jan26

POWERWALL 3 SYSTEM DESIGN GUIDANCE

v1.11 v21Jan2026

Design Considerations

Supported Configurations

• Up to (4) Powerwall 3 units can be installed with (1) Backup Gateway 2, with or without AC-coupled solar (see Appendix E: Installing Multiple Powerwall 3 Units and/or Expansion Units on page 138) 

• Up to (3) Expansion units can be connected to the Leader Powerwall 3 (see Appendix E: Installing Multiple Powerwall 3 Units and/or Expansion Units on page 138)

NOTE: Do not connect Expansion units to a Follower Powerwall 3 unit

• Only Tesla devices are compatible with Powerwall 3; no third-party equipment in lieu of Backup Gateway 2 or Tesla Remote Meter 

• Powerwall 3 is not compatible with the following: 

• Neurio remote energy meters (see Energy Metering on page 27 for more information) 

• Other batteries (Powerwall 2 or third party batteries) 

• Stacked units (Powerwall 3 must be mounted in a side-by-side configuration) 

• Third party MLPE solutions, such as optimizers, installed on the DC-coupled solar system. These devices may lead to erratic system behavior such as nuisance tripping on the Powerwall 3 when installed on the DC-coupled solar system. However, they can be installed on the AC-coupled solar system.

System Tie-in

• Backup systems must be one of the following: 

• 230 V single phase service 

  •  100 A or smaller service, or (in absence of a service rating) maximum 100 A of loads downstream of Backup Gateway 2 

• 230 / 400 V three phase service 

  • 80 A or smaller service, or (in absence of a service rating) maximum 80 A of loads downstream of Backup Gateway 2 

  • Follow all local requirements for balancing the system equally across the available phases

NOTE: Regardless of the number of Powerwalls installed, only one phase (L1, L2, or L3) will provide backup during a grid outage.

• A breaker is always required for Powerwall tie in. This breaker serves as an overcurrent protection device for Powerwall and must be wired in accordance with local wiring codes and regulations. See Powerwall 3 Specifications on page 5 section for breaker size.

NOTE: In line with relevant standards, Powerwall must be wired to support the maximum continuous current of the system.

• Powerwall 3 must always be connected to the Home terminals downstream of the Backup Gateway 2 

• Recommend that total Powerwall supply is able to power the single largest automatic load in the backup circuit

• Any/all loads on the backup circuit are adequately protected with an overcurrent protection device 

• All three phase loads or solar must be excluded from the backup circuit 

• All single phase loads in the backup circuit must be sized appropriately for the configured power output of the Powerwall (see Powerwall 3 Specifications on page 5 for power output options) 

• Site and solar monitoring must be installed to capture overall power flow to/from the site, as well as all solar production (see Energy Metering on page 27) 

• Powerwall and Backup Gateway 2 are rated for 10 kA of fault current.

Powerwall 3 Solar

Powerwall 3 has an integrated inverter and 3 MPPTs, with a maximum solar input of 20 kW DC.

NOTE: See AC-Coupled Solar System Sizing on page 26 for information about sizing AC-coupled solar with Powerwall 3.

System Sizing

The following resources explain how to size the Powerwall 3 system to meet customer expectations, as well as how to determine which loads can be included in the backup circuit and what to do with loads that cannot be included.

Backup Loads Supported per Powerwall Quantity

• The largest load on the backup circuit is limited by the quantity of Powerwalls; the largest load/breaker size each Powerwall can support is determined by the selected Powerwall breaker size and configured power output (see Powerwall 3 Specifications on page 5 for power output options).

AC Units and Large Motor Loads

Inrush current (largest instantaneous current draw when a motor starts) is limited to 185 A locked rotor amps (LRA) per Powerwall 3.

For air conditioner units, use locked rotor amps on equipment label as inrush current.

Design Options if motor locked rotor amps is greater than the number of Powerwall 3 units multiplied by 185:

• Increase number of Powerwalls

• Relocate AC unit/motor load out of backup circuit

Example:

• Motor Load unit with 200 A locked rotor amps

• Required Powerwall(s): (2) Powerwall 3 units required, so that 200 A < 370 A

NOTE: Double-check that the AC breaker follows the Powerwall breaker sizing rules.

EV Charging

*Ensure the configured power output is great enough to support the charger(s) on the backup circuit; for instance, if Powerwall 3 has a configured power output of 5 kW, (2) Powerwall 3 units would be required to support a Tesla vehicle charger. 

Powerwall coordinates with Tesla vehicles for enhanced vehicle charging. It will adjust the charging power to ensure it can continue to support the home loads without overloading itself, and will only charge the vehicle when the percentage of charge is higher than the limit set by the customer.