If you are in the market for a Tesla Powerwall, you may be wondering how long it will keep your electricity on in the event of a power outage.

After all, one of the main reasons people invest in a Tesla Powerwall is for peace of mind during power outages.

In this article, we’ll discuss how the Tesla Powerwall works, how long the Tesla Powerwall will keep your electricity on during a power outage, and how much power it can provide.

How Does The Tesla Powerwall Work?

Powerwall is a battery that can store energy for future use and works in tandem with solar to provide key security and financial advantages.

The Tesla app allows you to tailor the operation of the Powerwall system using owner customization features such as energy monitoring, metering, and smart controls.

Over time, the system learns from your usage habits and improves its functionality.

Related: Solar Battery Storage | What Are They? | How They Work?

With Solar

When the sun rises, solar energy begins to power your home. When extra power is required for the house, it may be drawn from the utility grid.

Solar panels generate more electricity than the home requires during the day, when Powerwall is charged by sunlight.

After that, the Powerwall stores that energy for later use, such as when solar production decreases or if there is a power outage.

Solar recharges Powerwall the next day when the sun comes out, running a cycle of clean, renewable energy.

Without Solar

Powerwall can charge when your utility’s electricity rates are low and discharge when they’re high, resulting in automatic savings.

Powerwall will also provide seamless backup power by detecting grid outages and immediately switching to become the home’s main power source.

How Much Electricity Will A Tesla Powerwall Provide?

The question of “how much?” is a really good place to start. And with that, you need a couple of pieces of info:

How much power does your home need?

How much power can the Tesla Powerwall provide?

Once you have answered those questions, you can then figure out how many appliances can your Powerwall run in your home.

The amount of juice that resides in batteries such as these is measured in kilowatts (kW) or amps (A). Amps are a measure of current, while kilowatts are a measurement of power.

The formula for converting amps to kilowatts is as follows: Here’s how many watts equal one kilowatt (to calculate watts, just divide by 1000):

Kilowatts = (amps x voltage) / 1,000

You can use this formula to determine the amount of power required to supply each device, and then compare the overall output with the Tesla Powerwall’s capacity.

How Much Power Do You Need?

To figure out how much power you’ll need, count up all of the appliances you want to back up.

To calculate this, either you or your installer will need to estimate the energy usage of each appliance in your home.

Once you have figured out what the wattage of each appliance is, you can then estimate how long you would like the Powerwall to keep your appliances running.

This will give you a good idea of how many kilowatt-hours (kWh) of storage you need.

How Much Power Can The Powerwall Provide?

Great! Now you can compare the amount of power consumed by your house to the Powerwall’s rating.

The instantaneous power and continuous power ratings for batteries like the Powerwall are important.

Instantaneous power

The amount of electricity it takes to get an appliance up and running is known as instantaneous power.

The power needed to start your car engine is an example of immediate power.

To begin, you’ll need a lot of power to start your equipment, but the consumption will plummet quickly after the initial start.

Check to see whether your appliances require a surge requirement

Instantaneous Power Rating of Tesla Powerwall = 7 kW

Related: How Much Does It Cost To Charge A Tesla? (COMPARISONS)

Continuous power

Continuous power is the power your battery can provide for an extended period of time without any loss in performance.

This is the power that you would use to keep your fridge running or to keep the lights on all night long.

Powerwall’s Continuous Power Rating = 5 kW

The amount of power that a battery can provide at once is important, but it doesn’t give the whole story.

For example, a battery with a high instantaneous power rating may only be able to provide that power for a short period of time.

A battery with a low instantaneous power rating may be able to provide power for a long time.

This is where the continuous power rating comes in. The continuous power rating tells you how much power a battery can provide for an extended period of time.

In general, you’ll want a battery with a high continuous power rating if you’re planning on using it for backup power.

This is because you’ll likely need to run your appliances for an extended period of time in the event of a power outage.

For batteries of this size, the continuous power rating is generally around 5-8 kW.

How Long Will The Tesla Powerwall Provide Power?

This is a great and important question…

It all boils down to 2 questions again:

Now, if your house has a solar panel system installed alongside your Powerwall, the usable storage capacity will be different.

This is because the solar panels will be constantly charging the Powerwall during the daytime.

As a result, you’ll have more power available to use at night or during a power outage.

The amount of time that your Powerwall can provide power for also depends on how much power you’re using.

If you have a lot of appliances that use a lot of power, the Powerwall will deplete its stored energy faster.

On the other hand, if you only have a few low-power appliances, the Powerwall will last much longer.

Usable storage capacity

The amount of electricity a battery can hold is measured in terms of usable storage capacity.

Because it reflects the usage of a specific quantity of power (kW) over a specific length of time (hours), usable storage capacity is measured in kWh.

Tesla Powerwall usable storage capacity = 13.5 kWh

In a nutshell, it means you can utilize 13.5 kW for one hour, 1 kW for 13.5 hours, or anything in between.

Duration of time you’re using each appliance

You’ll need to figure out which appliances you plan to use and for how long before moving ahead.

These calculations are based on the energy consumption of your chosen devices; below are some typical instances.

You may power a number of items with the Tesla Powerwall, including:

  • 3,500 W air source heat pump for just under 4 hours;
  • 300 W TV for 45 hours;
  • 200 W refrigerator for 67.5 hours;
  • Five 20 W light bulbs for 135 hours;
  • 25 W phone charger for 540 hours;
  • Or a 6 W WiFi router for 2,250 hours.

Don’t forget, you’ll be using these items in tandem with one another. Again, it’s important to remember that the duration of time you can use your devices will be affected by the power rating of each appliance.

The higher the power rating, the shorter the amount of time you’ll be able to use it.

It’s a good idea to figure out how much power the essential devices you’d want in the event of a blackout, such as your WiFi router and computer, require, then estimate how long the Powerwall will last.

Are You Pairing Your Powerwall With Solar?

The reason why it’s so important to ask this question is that it will directly impact the amount of stored energy in your Powerwall.

If you are installing a solar panel system at the same time as your Powerwall, or if you already have one, then your Powerwall will be constantly charging during the daytime.

As a result, you’ll have more power available to use at night or during a power outage.

If you just have a Powewall without a solar system, your Powerwall will only have the energy it stores from the grid.

This is why we always recommend pairing your Powerwall with solar. Not only will you be able to take your home off the grid in case of a power outage, but you’ll also have peace of mind knowing that you have backup power in case of an emergency.

Why Wouldn’t Solar Panels Alone Work?

Solar panels alone will not keep your house running when the power goes out. This is because, even with solar panels, your home is still linked to the grid so that it may send energy back to the grid and take from it.

During times when you are not generating as much energy as you use, your power would cease to function if your home was not connected to the grid (i.e., whenever the sun sets).

When the power goes out, all connections are immediately cut off, including those made with solar panels.

This is to safeguard the safety of anyone who may be working on the wires to ensure that they are not harmed while solar panels continue to provide power through the grid.

Alternative Power Solutions

Solar panels are not the only way to store electricity generated by solar panels. In fact, they can even power your home if the grid goes down. However, other options exist, such as battery backups.

The Tesla Powerwall is one such alternative, and it’s far superior to most of the existing battery backups on the market.

The Tesla Powerwall can keep your house powered for seven days (or more!) in its optimal configuration without you having to do anything.

You’d have to run out at least a few times with a normal generator, and it’s doubtful that your entire property would be powered.


How many years does a Tesla Powerwall last?

Tesla’s warranty on the Tesla Powerwall 2 is 10 years for unlimited cycles and 80% of the original energy capacity when charged with solar power. This means that if your Powerwall’s capacity is less than 80 percent during those ten years, you may be entitled to a replacement.

How many Powerwalls do I need?

In broad terms, one Powerwall should be able to cover your emergency circuits, lights, and outlets. If you want to power larger appliances such as a washer or dryer, 2-3 Powerwalls is a good place to start.

Can I install Powerwall myself?

Yes, you can install Powerwall yourself by simply plugging it into an existing circuit breaker box. However, we recommend that you consult with an electrician to ensure the safety of your installation.

What if I move? Can I take my Powerwall with me?

Yes! The Powerwall is completely portable, so you can take it with you when you move. Simply unplug it from your current home and plug it into your new one.

How is a Powerwall installed?

The Powerwall can be set up on the wall or on the floor, and both it and the Gateway have a variety of cable connections for custom installation. Installers may use their smartphone, tablet, or laptop to commission the Powerwall system. Installation should be done by a certified electrician.

About the Author

Passionate about helping households transition to sustainable energy with helpful information and resources.

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