Backup Reserve

Backup Reserve allows you to determine how much of your Powerwall’s stored energy will automatically be saved for backup power. With the ability to adjust your Backup Reserve in the Tesla app, you can control the level of energy security that your Powerwall provides during a grid outage.

How It Works

Your Backup Reserve represents a portion of your Powerwall’s stored energy. The remaining portion is allocated for Self-Powered mode or Time-Based Control mode. During an outage, your Backup Reserve becomes available, and Powerwall begins discharging to power your home. Depending on the duration of the outage, your Powerwall may discharge below your set reserve percentage. When the outage is resolved, your Powerwall will prioritize charging above your reserve percentage before resuming normal operation.

How to Set Up

To use the Backup Reserve setting, open the Tesla app and follow these steps:

  1. From the energy home screen, tap ‘Settings.’
  2. Adjust the slider according to your preferred backup reserve.

Note: Setting a backup reserve of 100% prevents use of Self-Powered mode or Time-Based Control mode. This will negatively impact the potential economic benefits of those modes and increase your reliance on the grid.

Low vs. High Backup Reserve

If you prefer to reserve more energy for use during a grid outage or if your area is more prone to outages, you can set a higher reserve percentage. If you prefer to optimize your Powerwall's performance in Self-Powered mode or Time-Based Control mode, you can set a lower reserve percentage.

If you set your reserve percentage below 20%, a ‘Low Backup Reserve’ indicator will be displayed, and your Powerwall may not have enough stored energy to provide backup support during an extended grid outage.

If a grid outage occurs while your Powerwall’s stored energy is below 5%, you will immediately lose power to your home, and Powerwall will save this energy and wait to recharge itself from solar the next morning. In the morning, your Powerwall will periodically provide power to your home until there is enough solar power available to both power your home and recharge itself. Learn more about Powerwall’s behavior during a power outage.