Backup Loads Supported per Powerwall Quantity
- The largest load in the backup
circuit is limited by the quantity of Powerwalls; each Powerwall 3 can support the largest load/breaker size of 60A.NoteWhen considering what Powerwall can back up, power is the most important factor to avoid poor customer experience from repeatedly overloading the Powerwall system. Customers are expected to manage their energy usage during an outage, so it is not recommended to factor in energy capacity when determining how many Powerwalls are needed for a system. For that reason, Powerwall 3 Expansion units do not usually impact the backup loads that can be supported by the system. Adding more Powerwall 3 Expansion units does increase energy capacity and duration during an outage.
- See the Powerwall Loads in Backup Cheat Sheet on Partner Portal for a summary of what can be included in the backup circuit depending on the number of Powerwalls installed
- See the multi-Powerwall installation appendix in the Powerwall 3 with Backup Switch, Powerwall 3 with Backup Gateway 2, or Powerwall 3 with Gateway 3 installation manual for requirements for installing multiple Powerwall units.
AC Units and Large Motor Loads
- Inrush current (largest instantaneous current draw when a motor starts) is limited to 185 A LRA per Powerwall 3.
- For air conditioner units, use LRA on equipment label as inrush current.
- Other motor loads – Code Letter per 2017 NEC Table 430.7(B), measure inrush via clamp meter identified by manufacturer as capable of measuring < 0.25 second inrush current, or oscilloscope if no code letter or LRA value is listed.
- Design Options if motor LRA is
greater than the number of Powerwall 3 units multiplied by 185A:
- Increase number of Powerwalls
- Relocate AC unit/motor load out of backup circuit
- Example:
- Motor Load unit with 200 A LRA and utilizes a 60A/2P Breaker
- Required Powerwall(s): (2) Powerwall 3 units required, so that 200A < 370A
NoteDouble-check that the AC breaker follows the Powerwall breaker sizing rules.
EV Charging
| Type of Electric Vehicle Charging | Compatibility |
|---|---|
| Tesla vehicle charging (Wall Connector or Tesla Mobile Connector) | 1 Powerwall |
| Third-Party Level 1 EV charging | 1 Powerwall |
| Third-Party Level 2 EV charging | 1-2 Powerwalls* |
*(2) Powerwall 3 units are required for third-party Level 2 EV chargers above 11.5 kW.
Per the Vehicle Charging During Outage feature, the system will adjust the charging power during an outage to ensure Powerwall can continue to support the home without overloading Powerwall, and will only charge the vehicle when the percentage of charge is higher than the limit set by the customer.