Tesla Powerwall installed on the side of a navy blue house

How to Optimize Your Tesla Powerwall During a Power Outage

Tesla Powerwalls may seem mysterious. Here, we break down the formula to make the battery work best for you during an outage.

Freedom Solar Power is committed to providing our customers with expert knowledge on not only the installation of the Tesla Powerwall but how to optimize it during an outage. We also want to help them understand their energy consumption.

Backup batteries can often seem mysterious, so we’re breaking down the formula to make the Powerwall work for you.

How long does the Tesla Powerwall last during an outage?

This depends. The lifeline of the backup battery is reliant on the user. If you conserve as much energy as possible, it might last four times longer than if you operate all your appliances normally.

The Tesla Powerwall is similar to a cell phone battery in terms of energy consumption. According to Apple, your battery should last through 10 hours of phone calls a day. If you’re running background apps, playing music, streaming games and making phone calls, it may last only five hours.

There are no guarantees or set number of hours of how long a backup battery will last during an outage because everyone’s house and energy consumption varies.

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How much energy does the Tesla Powerwall hold?

The energy capacity in one Powerwall is 13.5 kilowatt hours (kWh). A Powerwall holds a limited capacity for a limited duration. How you use the limited capacity during an outage determines how long your house will remain powered.

When the backup battery reaches the end of its energy storage, it’ll shut down and attempt to recharge. The Powerwall system can detect outages and automatically recharge through your solar panels if weather conditions are favorable. If snow or debris blocks the panels, they’ll be unable to recharge the Powerwall.

The Tesla Powerwall app monitors severe storms in your area and alerts you 24/7 to prepare for potential outages. The app tracks whether your solar panels optimize enough sunlight to pull into the Powerwall and keep your home powered during a long outage. It also alerts you when your stored energy has 10% of power remaining and enters standby mode.

What “whole home backup” mean for a Tesla Powerwall?

With whole home backup, all your 120 and 240 voltage appliances are connected to the Powerwall through one circuit. The user must manually shut off the 240 voltage appliances in the event of an outage to conserve power.

If the Powerwall stays connected to heavy loads, it’ll drain the energy reserve faster than if connected to a partial home backup that automatically shuts them off. It’s vital for Powerwall users who opt for whole home backup to understand that it does not mean you can operate your home at full capacity. You must also rely on critical loads during an outage.

Appliances you can run off a Tesla Powerwall during a power outage

An average American home uses 28-50 kWh a day, depending on geographic location, season and personal electric usage. To efficiently use this 13.5 kWh system in an outage, the user must focus on critical loads and avoid or reduce heavy loads that would drain it quickly.

Critical loads supported are 120 voltage appliances. These include plug-in items, light bulbs, ceiling fans, refrigerators, small kitchen appliances (e.g., microwaves, toasters), televisions, computers and small handheld devices. Using only small-load 120 voltage appliances during an outage — and only as needed — is the most efficient way to keep your Powerwall on. 

The data listed above is based off an average American household consumption rate in 2021 from U.S. Energy Information Administration. Every home varies in consumption metrics due to usage, geographic location and appliances. This data should be used as a general guideline with no guarantee that your home uses the same amount.
The data listed above is based on an average American household energy consumption rate in 2021 from U.S. Energy Information Administration. Every home varies in consumption metrics due to seasonality, geographic location, type and use of appliances. This data should be viewed as a general guideline with no guarantee that your home will use the same kilowatt-hours.

Appliances you should limit or avoid during a power outage

Knowing which appliances to avoid during an outage will be your biggest asset in determining how long your house stays powered. The 240 voltage heavy load appliances to avoid or limit include an oven or range, clothes dryer, electric water heater and furnace, electric vehicle charger and HVAC at temperatures that the system struggles to maintain (i.e., under 78° in the summer and over 68° in the winter).

Turning off the HVAC will benefit you the most. In turn, using ceiling fans or plug-in heaters will regulate the temperature with a much lower consumption rate.

How to Optimize your Tesla Powerwall during a power outage

  1. Turn off HVAC and electric furnace. Turn on ceiling fans or plug-in heaters to regulate temperatures.
  2. Unplug electronic appliances such as video game consoles, televisions, Wi-Fi devices and stereos if they’re nonessential.
  3. Unplug countertop appliances such as a microwave, coffee maker, blender and toaster when not in use.
  4. Do not cook with an electric oven or range. Keep nonperishable food items on hand. Ideally, these foods don’t require cooking or can be cooked with the small countertop appliances listed in No. 3.
  5. Avoid taking hot showers, washing clothes, drying clothes or running the dishwasher. Electric heating units drain your Powerwall quickly.
  6. Charge your electric vehicle before a possible outage in case of an emergency when you must drive it.
  7. Turn off your pool pumps in the summer. In the winter during a freeze scenario, leave the pool pump on if you’re concerned about your pipes freezing.

To save the most electricity during an outage, switching the products in your home cushions your Powerwall from extracting energy too rapidly. Try these methods to conserve energy:

  • Transition to LED light bulbs.
  • Adopt a high-efficiency HVAC.
  • Replace your windows with double-pane glass.
  • Switch to smart kitchen appliances and a smart thermostat that adjusts to outdoor temperatures.

Making these changes gradually will lower your consumption and protect your home in the event of an outage. This makes the Powerwall work smarter, not harder.