Vehicle Charging During Power Outage

Powerwall coordinates with Tesla vehicles for enhanced vehicle charging during a power outage without exceeding the energy and power capabilities of your Powerwall. Powerwall continuously responds to the changing power needs of your home and will slow or stop your vehicle's charging to keep your home loads powered.

Connector icon

Charging Threshold

The charging threshold lets you balance your home and transportation energy needs, putting you in full control of your energy ecosystem. You can control your charging threshold on the 'Settings' screen for your home in the Tesla app.

The charging threshold determines how much energy Powerwall can share with your vehicle, and directs Powerwall to stop charging your vehicle when it discharges below your set percentage. Sharing more of Powerwall’s stored energy with your vehicle may decrease the potential backup duration for your home.

Threshold icon

Charging Current

During a power outage, or while off-grid, your Tesla vehicle will charge at up to the max charging current set in your Tesla vehicle. As your home loads vary, Powerwall will limit your vehicle’s charging current to ensure Powerwall can continue to support your home.

Outage icon

Power Outage While Charging

When a power outage happens, Powerwall will continue, slow or stop charging any connected Tesla vehicle based on Powerwall’s stored energy and your set threshold. If charging stops, you’ll be able to resume vehicle charging by lowering your charge threshold, waiting for the power outage to end or waiting for solar to recharge your Powerwall above your threshold.

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Solar Integration

If your home is equipped with solar and your vehicle is plugged in and charging while the sun is shining, Powerwall will continue to share any surplus solar with your vehicle after Powerwall discharges to your set energy threshold. Sharing surplus solar helps you maximise the value of your solar installation, even during a power outage.

Powerwall’s stored energy will remain at your set threshold as long as there is surplus solar available. Powerwall will automatically stop charging your vehicle and will begin to discharge to power your home when there is no longer surplus solar to support vehicle charging.

Connector icon

Charging Threshold

The charging threshold lets you balance your home and transportation energy needs, putting you in full control of your energy ecosystem. You can control your charging threshold on the 'Settings' screen for your home in the Tesla app.

The charging threshold determines how much energy Powerwall can share with your vehicle, and directs Powerwall to stop charging your vehicle when it discharges below your set percentage. Sharing more of Powerwall’s stored energy with your vehicle may decrease the potential backup duration for your home.

Threshold icon

Charging Current

During a power outage, or while off-grid, your Tesla vehicle will charge at up to the max charging current set in your Tesla vehicle. As your home loads vary, Powerwall will limit your vehicle’s charging current to ensure Powerwall can continue to support your home.

Outage icon

Power Outage While Charging

When a power outage happens, Powerwall will continue, slow, or stop charging any connected Tesla vehicle based on Powerwall’s stored energy and your set threshold. If charging stops, you’ll be able to resume vehicle charging by lowering your charge threshold, waiting for the power outage to end, or waiting for solar to recharge your Powerwall above your threshold.

Solar icon

Solar Integration

If your home is equipped with solar and your vehicle is plugged in and charging while the sun is shining, Powerwall will continue to share any surplus solar with your vehicle after Powerwall discharges to your set energy threshold. Sharing surplus solar helps you maximize the value of your solar installation, even during a power outage.

Powerwall’s stored energy will remain at your set threshold as long as there is surplus solar available. Powerwall will automatically stop charging your vehicle and will begin to discharge to power your home when there is no longer surplus solar to support vehicle charging.

Detailed Charging Behavior

 

POWER STATE HOME ELECTRIC LOADS CHARGING BEHAVIOR
On Grid Any Load Vehicle charges as normal
Power outage with Powerwall above energy threshold (or optionally with surplus solar) Low Loads Vehicle charges with surplus power and energy
High Loads Vehicle slows charging to prioritise your home loads
Power outage with Powerwall below energy threshold Any Load Vehicle stops charging

 

Your Tesla vehicle will display a status message on the interior display if Powerwall slows or stops your vehicle charging session. Vehicle charging may not automatically restart if charging stops.

Most charging issues can be resolved by reseating the charging handle. In the unlikely event that your charging connector is unresponsive, restart power for the connector, or press the 'Reset' button.

Compatible Home and Vehicle Configurations

This coordinated charging feature is available for Tesla vehicles using any wall connector, including Tesla Wall Connector and Mobile Connector. Your wall connector must be on a circuit backed up by Powerwall. If your Powerwall does not provide whole home backup, your wall connector should be located on your essential loads sub panel to support charging during a power outage. This feature behaves identically for owners with an off-grid Powerwall.

During a grid outage, Powerwall provides single-phase electric power. Note that vehicle charging is expected to be slower on single-phase electric power.

To charge your Tesla vehicle during a grid outage using a three-phase Tesla Wall Connector, Powerwall must be configured to provide backup power on L1, and Tesla Wall Connector must be connected to the backup circuit. If using a third party three-phase charging connector, please refer to documentation from its manufacturer.

Charging during a power outage will not affect the overall life of Powerwall or your vehicle’s battery. Tesla vehicles charging from your Powerwall during a power outage do not need to be connected to your Tesla Account, and no internet connection is necessary to support this charging feature.

Solar Inverter Compatibility

The mechanism used to manage vehicle charging while off-grid may not be compatible with all solar inverters. Powerwall makes slight frequency adjustments to your home’s AC power to control vehicle charging during a grid outage. Although solar inverter standards allow for full power output over the frequency range used to curtail vehicle charging, some solar inverter manufactures may have different interpretation of this standard, or some settings within the solar inverter may have been adjusted, which makes them incompatible. For this reason, a compatibility test is recommended between your solar inverter and this feature.

Please follow the steps below to complete the compatibility test.

  1. On a sunny day when Powerwall’s stored energy is between 50% - 80%
  2. Set the off-grid charging feature threshold in your Tesla app to 85%
  3. Observe the power output of your solar inverter
  4. Turn off the Main Switch (Grid Supply) in your switch board
  5. Check to see if the solar inverter maintains its output power? If not, wait 6 minutes to see if full power restored?
  6. If the solar inverter resumes full Power operation after 6 minutes, switch off the Main Switch (Solar Supply)to the solar inverter, leave it off for one minute then switch it back on again.
  7. Check to see if the solar inverter returns to full Power after 6 minutes?

 

If at points 5 and 7 and your solar inverter returned to full power it is compatible with this feature. If your solar inverter did not return to full power at points 5 and 7 then please contact Tesla support on 1800 646 952 to discuss this feature and reference the date and time of your compatibility test.

Supported Versions

  • Powerwall: 1.46+
  • Tesla Mobile App: 3.10.2+
  • Model 3/Model Y – North America: 2019.40.1+
  • Model S/Model X (2014 and later) – North America: 2020.32+
  • All Tesla Vehicles in Other Regions: 2020.40