Troubleshooting a System with Powerwall 3Expansion

Issue: Battery Expansion - CAN Termination Issue Alert in Device Setup

This alert is expected when the Expansion Harness port is open (port cover has been removed and no Harness is connected) or when the Expansion Harness is not properly connected.

To correct this issue, unplug the Harness, then plug it in again, ensuring it is fully seated and the gasket is not visible. Tighten the T40 bolt on the connector to 100 in-lb (11 Nm).

Issue: A Powerwall 3Expansion is not appearing when scanning for devices during Device Setup

  1. Confirm which Powerwall 3 is the Leader (this is the unit connected to the Backup Gateway / Backup Switch via communication wiring).
  2. Confirm the Expansion unit is connected to the LeaderPowerwall 3 via Expansion Harness.
  3. If the Expansion unit was connected to a Follower Powerwall 3, disconnect the Expansion Harness and connect it to the Leader or to another Expansion unit.
  4. Inspect the Expansion Harness:
    1. Inspect the Harness for damage, and ensure the T40 bolt on the connector is tightened to 100 in-lb (11 Nm).
    2. On each end of the Harness connector, perform the following continuity checks:
      • -HV jaws
      • CAN- jaws
      • CAN+ jaws
      • +HV jaws
      Informational PurposesAn informational icon, calling your attention
      Note
      If multiple Expansion units are not appearing the Devices tab, for instance if Expansion unit 1 appears but units 2 and 3 do not, begin with the Expansion Harness connecting units 1 and 2.
    3. Try connecting a different Expansion Harness.
  5. If the issue persists, contact Tesla Support.

Issue: One or more Powerwall 3Expansion is not charging to full capacity, or is taking a long time to charge

  1. If the Expansion units are wall-mounted and are all connected on one side of Powerwall 3, confirm the maximum combined Harness length (4 m / 13 ft) has not been exceeded:
    Informational PurposesAn informational icon, calling your attention
    Note
    The following table provides all allowable Harness combinations for this configuration:
    Harness 1Harness 2Harness 3
    4 m (13 ft)1875157-40-x--
    2 m (6.5 ft)1875157-20-x2 m (6.5 ft)1875157-20-x-
    2 m (6.5 ft)1875157-20-x0.5 m (20 in)1875157-05-x0.5 m (20 in)1875157-05-x
    0.5 m (20 in)1875157-05-x0.5 m (20 in)1875157-05-x0.5 m (20 in)1875157-05-x
    Informational PurposesAn informational icon, calling your attention
    Note
    The Expansion Harness length is part of the part number printed on the label on the side of the connector:
  2. If the maximum combined Harness length has been exceeded (for instance, (2) 4 m Harnesses have been used), there are two options to correct the installation error:
    • If possible, use shorter Expansion Harnesses to connect the units, reducing the total combined Harness length to 4 m (13 ft) or less
    • Move (1) Expansion unit to the opposite side of Powerwall 3; there is no limit on the maximum combined Harness length when Expansion units are connected on both sides of Powerwall 3