Best Practices for Tesla Powerwall for Power Outages

Best Practices for Tesla Powerwall for Power Outages

When you are at home, solar panels are a great way to reduce energy costs. With the Tesla Powerwall, you are geared up for any situation—but what happens if there is a power outage?  

The Tesla Powerwall will continue to work normally when power outages occur. They are like a generator in that they can power the household if the primary power source goes down.

Whether you want to use it only as a backup source of power or entirely convert your home to run on renewable energy, the Tesla Powerwall is for you. In this article, we will discuss how the Powerwall can continue providing your home with the electricity it needs during power outages.

How the Tesla Powerwall Works

Tesla has been a revolutionary company with their inventions and innovations that have served communities throughout the world. While they are mainly known for the Tesla automobiles, the company has also created other products, including the Tesla Powerwall.

The Tesla Powerwall is a rechargeable home battery system that uses a solar panel system to capture and convert sunlight into energy; this is done with three essential parts:

  • The panels have the easiest job of the three: they sit in a well-lit area, usually on the roof of a house—but sometimes on the land—and capture the sunlight to convert it to electricity.
  • The inverter (in this case, the Powerwall) is connected to the solar panels. It takes the electricity that the panels have converted and stores it in its batteries. The electricity will be held here until it is ready to be used inside the residence.
  • The solar gateway is simply the device that tracks how much electricity is being used by the household and how much electricity is still available.

In other words, when sunlight is directed onto the solar panels, the panels can collect the solar power and convert it to energy, which is then stored in the Powerwall for immediate or later use.

How Does the Tesla Powerwall Work without Power?

How the Powerwall would operate without power is the same way it would when there is no sun available; it simply uses the energy that was stored throughout the day.

If you have not been using solar power continually, there should be a reserve amount in the Powerwall’s inverter that will allow you to use that energy to power the household and your devices in the event of an outage.

In contrast, with other backup power systems like a generator, you have to have another energy source, most of the time gasoline, to use the generator to restore power. You also have to physically fill the generator with the gas for it to function as well.

With that said, for those who live in an area where power might go out more frequently (high-temperature areas, areas susceptible to natural disasters, etc.), having the Powerwall as a backup system might make more sense than spending money on a generator and gasoline, or taking the extra time to get the generator set up.

Preparing for Power Outages with the Powerwall

When you are prepared for emergencies, you are more likely to get through them without as many hassles. Preparation is critical, and with the Tesla Powerwall, you can prepare yourself and your household for any impending outages.

With the Tesla Powerwall, you have the option to directly divert any power stored in your system to fulfill the power needs of your household with the click of a button. In effect, you can change the settings of your Powerwall to prepare for any outages that might come.

With the Tesla App, all you have to do is change the settings on your Powerwall system to reflect your goals. On the app’s homepage, go to “Customize” and select “Backup Only Mode.” There is a slider that also allows you to choose a percentage of the power collected during regular use to be diverted for the “Backup Only” mode.

Best Practices for Using the Powerwall During Power Outages

When the power goes out in your house, there is always a moment of panic. The large appliances that you usually rely on to function daily are almost irrelevant in the hours and days coming ahead without power.

But, if you have the Tesla Powerwall system as a backup, there is a chance you can go about your day as usual.

The best part about the Powerwall is that it takes less time than almost all other backup power sources to kick in. When the power goes out, the Powerwall automatically will kick in, and within seconds, your energy will be restored.

However, if you want that power to last and be used as efficiently as possible, follow these best practices during a power outage:

Limit Power Use Among Appliances

The Tesla Powerwall, being the backup system it is, can generate enough power to sustain a household when the power goes out. But, if the power is supposed to be down for quite some time, it might be smart to conserve as much energy as possible. With that said, the Powerwall has excellent features that allow for selecting which appliances to power.

If you want to conserve energy when there is a power outage, the Powerwall system, with the Tesla app, allows the owner to control the power being put into the household. The owner can limit how much energy is being used, and in some cases, which appliances can use the power.

The best appliances to keep on during a power outage will be ones that you will likely use the most during a blackout or to maintain the quality of certain items. This would include specific sockets to charge mobile phones or your refrigerator to keep your food fresh.

Appliances that you will want to direct power away from are those that are larger and take up more energy, plus devices you will likely not use during an outage. This will include:

Turn on Notifications on the Tesla App

The Tesla app allows you to enable push notifications to your mobile device if there is an outage while you are away from home. From there, you can use the app to manage your energy use and direct power to appliances that need it the most.

To turn the notification feature on, just go to your app’s settings and tap “Notifications.”

Set Up Storm Watch and Preconditioning Modes

The great thing about the Powerwall system is that you can have a ton of control over your system through the Tesla App. Two of the best features are the Storm Watch and the Preconditioning modes.

Storm Watch Mode

The Tesla app communicates with the National Weather Service to predict whether there may be a chance for an outage. If there is a sign that potentially dangerous or severe weather is approaching the area, the Storm Watch feature will notify you.

Simultaneously, the mode will prepare the Powerwall system in case of an outage from the storm, triggering the device to begin storing energy to use later.

Preconditioning Mode

The Powerwall’s preconditioning mode prepares the device for outages or potential malfunction due to other weather conditions, such as extreme freezing temperatures.

Once temperatures start to drop below the freezing threshold, the Powerwall will begin setting aside a small amount of energy to stay at the proper temperature it needs to remain operational.

Check Appliance and Device Compatibility Before Installation

It is worth noting that although you can select which appliances can use the Powerwall during an outage through the Tesla app, this does not mean the Powerwall will be able to power those appliances or other electronic devices.

Before you have a Powerwall installed, be sure to check your devices and appliances to ensure they can be powered on the Tesla Powerwall system. If they are compatible, make sure that you have enough Powerwalls to support those items.

Invest in Multiple Powerwalls to Backup Large Appliances

There are many different options for installation of the Powerwall system, with the opportunity to add multiple Powerwalls to your household to power more powerful and/or larger appliances. The more Powerwalls you have installed, the more devices and machines that can be powered.

The following list of essential appliances may need more than one Powerwall to maintain enough power to operate normally during an outage:

Main Electrical Panel

For any number of Powerwalls installed, lights, electrical outlets, and 120v small appliances, they will all be powered by a single Powerwall. However, as mentioned above, the more Powerwalls installed, the more power you can provide to multiple items.

Air Conditioning Units

To check how many Powerwalls are required to support your air conditioning unit, check the Locked Rotor Amp (LRA) found on the unit’s nameplate. See if the LRA is lower than the Running Load Amps (RLA) or if there is no number next to the LRA.

If either of these is the case, then you only require two Powerwalls to operate the air conditioning unit. If, however, the RLA is greater, you will need three Powerwalls.

Well Pumps

Well pumps are compatible with Powerwalls if they are less than 20 amps and have a horsepower of less than one. If this is the case, you only need a minimum of two Powerwalls.

Other Large Appliances

For other large appliances or devices that require a significant amount of energy to work, such as a Tesla EV charging station, at least two Tesla Powerwalls must be installed in the household to power them.

Note: For Tesla vehicles, only two Powerwalls are required to charge the car; all other electric vehicles will need at least three Powerwalls. If you are powering more than one electric vehicle in the house, you must, accordingly, increase the number of Powerwalls installed in your home.

For homes with three Powerwalls, in addition to the appliances listed above, you can also power a second compatible air conditioning unit, an electric water heater, pool equipment, and an electric dryer.

Using the Powerwall as Your Main and Backup Energy Source

Until now, we have discussed how you can use the Tesla Powerwall as a generator in case of a power outage. However, what if you wanted to use the Powerwall as your home’s primary source of energy too?

Fortunately for Powerwall owners, this is indeed possible—as long as you live in an area with ample sunlight throughout the year. The Tesla Powerwall can be your primary power source for those hot summer months when electricity bills usually are through the roof, or 365 days a year.

If you only want to use the Powerwall during peak energy usage, you can transition back and forth between the Powerwall’s energy and the electricity grid’s energy seamlessly. There will be no difference in the generated electricity and how it can power your appliances; they will still function like normal. The only difference is that they will be powered by the sun.

How Many Powerwalls Are Needed to Backup the Whole House?

If you want to use the Tesla Powerwall as your primary energy system and during power outages, Tesla offers a few installation methods to fit your needs. First, choose whether you want a whole-house backup system or just a partial house system.

Partial House Backup System

With the partial house backup system, you can pick which appliances and electrical devices you wish to charge with a single Powerwall.

A drawback of the partial house system is that larger appliances like air conditioning units and the range/oven cannot be used. These appliances require too much power to be operated, which would overload the system.

Whole House Backup System

For the whole house backup system, there are several options. The most basic house-wide system has just one Powerwall, which allows basic appliances to be powered with limits on how much time they are powered.

But, as mentioned earlier, a great feature of the Tesla Powerwall system is that you can have multiple Powerwalls installed in your home, leading to larger appliances and even electric vehicles being charged.

For the whole house backup system, you will most likely need at least two Powerwalls installed. These can be installed either side-by-side or front-to-back.

Backing Up the Entire Home During Outages

If you regularly rely on your Powerwall to generate electricity for your entire home, you may have some concerns about whether its stored energy can last through a blackout situation.

For those in situations where the power goes out and/or might not be back on for multiple days, having at least two Powerwalls with a solar panel system is a great idea.

As long as there is sunshine overhead, your solar panels will always be working and converting the sunlight into electricity—even when the power is out. There is no need for electricity from the power grid to operate the Powerwall system.

However, if there is reduced sunlight during a power outage, try your best to conserve the energy from your Powerwall using the tips mentioned above. Just like using it as a backup generator, you should allow only specific, necessary appliances to pull power from the system.

How Long Can a Powerwall Provide Backup Energy?

You may not think about how much energy your Powerwall might have left during daily use, but it becomes critical once the power goes out—especially at night or on cloudy days where it may not be able to regenerate its energy through solar power.

Fortunately, you will likely not have to worry about ever running out of energy during an outage; the Powerwall allows for 5kW of continuous power when the normal power grid goes down.

However, in the event that your Powerwall does not have a lot of energy available to backup appliances during an outage (which is usually the case for long-term blackouts), there are a few things the device can do to help alleviate this issue:

(Source: Tesla)

In Summary

One of the primary benefits of having the Tesla Powerwall is using it as an additional backup energy source in case of an emergency, like a power outage. It restores electricity to your home in a fraction of a second, allowing you to continue using the power as usual.

Because the Powerwall runs on solar power, you never have to worry about running out of electricity as long as it is sunny outside. If it happens to be nighttime or cloudy during an outage, there is still no cause for concern; the Powerwall stores and can limit its energy use to only essential appliances and devices to make its power last as long as possible.

Solar Discounts:


The articles here on are created by Greg, a Tesla vehicle and Tesla solar expert with nearly half a decade of hands-on experience. The information on this site is fact-checked and tested in-person to ensure the best possible level of accuracy.

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