Powerwall is configured to meet your home’s specific energy needs. Use the Tesla app to monitor and manage your solar system’s performance with features and control modes such as Backup Reserve, Self-Powered and Time-Based Control. When temperatures are below freezing, Preconditioning is enabled, heating your Powerwall to improve operation and charging performance.
Learn more about the following modes for your Powerwall:
With Backup Reserve, your Powerwall provides you with energy security during a grid outage. Set your preferred reserve percentage by adjusting the slider at the top of the ‘Settings’ screen.
If you prefer to reserve more energy during a grid outage, or if your area is more prone to outages, you can set a higher reserve percentage. If you prefer to optimise your Powerwall performance when Self-Powered or Time-Based Control mode is enabled, you can set a lower reserve percentage.
During an outage, your Powerwall may discharge below your reserve percentage. When the outage is resolved, your Powerwall may charge above your reserve percentage. To use your Powerwall as a backup-only appliance, select Self-Powered mode with a backup reserve of 100%.
When Self-Powered mode is selected, your Powerwall stores solar energy not used during the day to power your home at night. Your Powerwall will charge when excess solar power is produced, and this stored energy will be used when your home requires more power than your solar system can provide.
When you produce enough solar energy to offset all consumption, and your Powerwall is fully charged, you will export excess energy to the grid. Similarly, when you consume more solar energy than is available from your solar system and Powerwall, you will import energy from the grid.
Self-Powered mode approximately doubles the amount of solar energy that powers your home and is the most effective way to reduce your carbon footprint and gain energy independence. Learn more about energy data and impact cards in the Tesla app.
How to Set Up Self-Powered
Step 1: From the home screen, open the ‘Settings’ menu.
Step 2: Under ‘Set Control Mode,’ select ‘Self-Powered.’
Step 3: Set your preferred Backup Reserve by adjusting the slider at the top of the screen.
Note: Setting a higher reserve percentage saves more energy for protection during an outage, while setting a lower reserve percentage optimises energy allocation for your Powerwall when Self-Powered mode is selected. Consider your personal economic needs and energy security outlook when setting Backup Reserve.
Time-Based Control (also referred to as load shifting) helps you maximise savings through smart charging and discharging of your Powerwall. If your electricity prices vary during the day, you are likely on a time-of-use plan, and Time-Based Control would present the best economic value for your system. Time-of-use plans are utility rate structures where electricity prices may vary depending on the time of day, the day itself or the season.
Utilities usually break time-of-use plans into three periods:
- Peak: High energy demand hours with most expensive prices
- Off-Peak: Low energy demand hours with least expensive prices
- Partial Peak or Shoulder: All other times
How to Set Up Time-Based Control
Before setting up Time-Based Control mode, obtain your specific time-of-use plan, which is typically found on your electric utility website.
Step 1: From the home screen, open the ‘Settings’ menu.
Step 2: Under ‘Set Control Mode,’ select ‘Time-Based Control.’
Step 3: Set your preferred rate plan by tapping ‘Edit Custom Rate Plan.’ You can set custom rate plans for the week by switching between ‘Weekdays’ and ‘Weekends’ at the top of the screen.
Step 4: Tap the ‘Off-Peak’ section and select your ‘Start’ and ‘End’ times. Then, tap the back icon, and repeat this step for the ‘Peak’ section.
Step 5: Set your preferred Backup Reserve by adjusting the slider at the top of the screen.
Note: Consider your personal economic needs and energy security outlook when setting Backup Reserve. Setting a higher reserve percentage saves more energy for protection during an outage, while setting a lower reserve percentage optimises energy allocation for your Powerwall when Self-Powered mode is selected. Consider your personal economic needs and energy security outlook when setting Backup Reserve.
Powerwall continuously runs an energy forecast, learning the patterns of your energy use and seasonal solar production. This energy forecast allows your Powerwall to optimise your energy usage. If the forecast shows that you are likely to use energy at a high-cost time, Powerwall prioritises charging during low-cost periods and discharging during high-cost periods.
Note: Since this smart forecasting needs time to learn about your energy usage, Time-Based Control requires approximately a week before becoming a selectable control mode.
If eligible, your Powerwall will automatically charge from the grid during off-peak periods to offset your use during peak periods, based on your energy forecast’s estimated usage.
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. Preconditioning, in combination with Tesla’s unique liquid thermal management system, allows your Powerwall to operate at lower temperatures than any other home battery.
You cannot customise 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.
Frequently Asked Questions
Why doesn’t my Powerwall charge to 100% during the night (cost saving mode)?
Powerwall continuously runs an energy forecast, learning the patterns of your energy use and seasonal solar production. This energy forecast allows your Powerwall to optimise your energy usage and it may not always be deemed optimal to charge to 100%. For example, your system might be expecting some excess solar production later in the day, so it would leave some capacity available to absorb any excess solar.
Should I adjust the settings frequently by switching modes?
No. For optimal usage of Time-Based Control the system should remain in the same mode. It is not currently compatible with agile energy tariffs.
Can I force my battery to charge?
Under normal conditions, to achieve the maximum economic benefit, it is best to allow Powerwall to operate autonomously in Time-Based Control mode and let it decide when to charge. For this reason, there is no force charging control available to the user within Time-Based Control. However, should you have a specific need for more energy in the battery due to an event that could not easily be anticipated and is very much out of the ordinary for your home, it is entirely possible to switch to Self-Powered Mode and set the desired backup percentage. This will cause the Powerwall to charge to that level, after which you can revert to Time-Based Control mode. Changing the backup reserve percentage is only possible on Gateway 2.
How long does the system take to learn my energy consumption patterns?
The system starts learning from the moment the site is operational. As it learns it will improve, so the longer the site is operational, the more it will optimise operation. The algorithm uses data from the last year to determine forecasts.
Why is my Powerwall not doing what I want it to?
Your Powerwall system would not be able to predict unexpected behaviour. For example: You run your washing machine every day at 16:00. One day you have an unexpected appointment and need to run your washing machine at 08:00. This means your Powerwall system might not have enough energy available to power the washing machine, as it was perhaps expecting to charge from solar in the middle of the day and power your washing machine in the late afternoon.
Why is my Powerwall not charging from the grid at 5 kW? (cost saving mode)
The most efficient charging rate for the Powerwall is 3.3 kW. It will therefore charge at that rate when charging from the grid. This will keep battery degradation to a minimum. If there is a compelling economic reason to charge faster, the system might decide to charge up to maximum capacity.
Why is TBC mode not available in my App?
It could take up to 48 hours after commissioning to activate TBC mode in your app.
Why is my Powerwall not forecasting solar production accurately?
Powerwall uses historical data about solar production on your site to generate its own local forecast at regular intervals. It is expected that these forecasts will be somewhat inaccurate, especially during highly variable weather. As such, the system then makes corrections based on actual measurements throughout the day.
Powerwall used to charge fully from the grid every night now it doesn’t anymore (cost saving mode)
There may be seasonal variations in TBC behaviour based on the amount of available solar energy. So, systems may import more energy from the grid during winter months to make up for the lower solar production.
Will my Powerwall charge during the entire off-peak period? (cost saving mode)
No, the forecasting system will determine for how much of the off-peak period the Powerwall will charge. This may be less than the entire off-peak period. The system might discharge during off-peak periods if it deems it to be the most cost-effective option. For example, if the Powerwall is full of solar energy and expects more solar energy to come later, it might decide to serve the load during off-peak periods to make space in the battery for more solar energy.