Additional Powerwall Modes
Powerwall also has two special modes: Preconditioning and Storm Watch. For both, Powerwall identifies unique situations and automatically switches to the mode most able to enhance performance. You will not be able to select or adjust these special modes.
When temperatures are low, all batteries have a reduced ability to charge. To help Powerwall counteract this, Powerwall uses Preconditioning. When temperatures are below freezing, Preconditioning turns on and heats your Powerwall to improve operation and charging performance.
To heat itself, Powerwall draws a small amount of energy, which then allows high-power charging. During a cold night, your Powerwall automatically preheats before sunrise so that maximum solar energy can be captured during the day.
You cannot customize this mode because Powerwall can best detect its internal temperature and knows when to enable Preconditioning.
During Preconditioning, the Power Flow screen may show energy flowing to your Powerwall from solar or the grid. This is normal behavior, and the energy is only being used to heat, not to charge.
During winter months, a small amount of your Powerwall capacity is reserved to improve performance in cold weather. This may change your visible total capacity in the Tesla app. Rest assured, your total capacity has not changed – this small reserve is just set aside to improve performance.
Preconditioning, in combination with Tesla’s unique liquid thermal management system, allows your Powerwall to operate at lower temperatures than any other home battery.
Severe weather is the leading cause of power outages. Storm Watch mode allows you to maximize savings by keeping a low reserve percentage in Self-Powered or Time-Based Control mode, while still having peace of mind that Powerwall will protect you during a severe weather event.
Powerwall communicates with the National Weather Service to know when severe weather is on the horizon and automatically triggers Storm Watch. This mode pushes the limits and charges Powerwall to maximum capacity so it can provide backup power.
When activated, the Tesla app will notify you that you are now in Storm Watch mode. This remains active until the weather event ends. After, the system returns to its previously selected mode. Although you cannot turn on Storm Watch or adjust it, you can disable this mode altogether by going to the Tesla app, selecting 'Customize' and adjusting the slider next to 'Storm Watch'.
Note that Storm Watch only activates during severe storms that are likely to knock down power lines and cause outages, like hurricanes and ice storms. To best protect yourself from everyday weather events, keep a high reserve percentage or choose Backup-Only.
As your Powerwall learns more about the type of storms that typically cause outages, events that trigger Storm Watch will be adjusted.