Tesla Powerwall battery warranty complete overview

Let's face it – warranties aren't the easiest (or most gripping) documents to read. There are often a lot of details and fine print included that can be hard to digest, leaving many to wonder: what does the warranty actually cover? Am I vulnerable? Anything I might be missing?

To make it as easy as possible, we've read warranty documents for the top solar battery manufacturers, talked to them to confirm what is and isn't included, and plan to point out the most important aspects of each in a series of articles. For this article, we reviewed Tesla's Powerwall warranty.

Tesla is one of the most recognizable companies in the clean energy industry, with impressive forays into solar, storage technology, and electric vehicles. Their Powerwall is one of the most popular energy storage options currently offered on the market.

This is an unbiased review: EnergySage is not paid to review brands or products, nor do we earn money from affiliate advertising in this article. The content of this blog is based on research and information available at the time of writing. Learn more about our mission and how we make money as a company.

Tesla's Powerwall is credited with popularizing solar batteries for residential use. Similar to their successful rebranding of electric vehicles, Tesla's Powerwall brought residential battery storage increased popularity and brought them into the mainstream market. While the Tesla Powerwall certainly is not the only residential storage product on the market, it has remained one of the most popular since it was first announced in 2015.

Tesla's warranty offering is very competitive compared to others in the industry. Crucially, although the Powerwall warranty runs for ten years, Tesla provides an unlimited-cycle warranty, which is unique. They also offer 24/7 support for issues relating to their Powerwall. And, since most issues with the Powerwall are related to software rather than hardware issues, most issues can be resolved without a site visit. However, it's worth noting that Tesla will not honor their warranty if the Powerwall has not maintained consistent internet access throughout its life due to the importance of online software updates to its functionality.

A battery manufacturer's product and performance warranty covers the integrity and output of the equipment itself – if your battery system has a defect or experiences unreasonable degradation, that should be covered by your product warranty. If there's a defect with your battery, you or your installer should be able to tell that something is amiss and fix the problem immediately–often before the battery is ever installed. Regardless, it's good to consider products with longer warranties for the peace of mind it provides.

Tesla includes a 10-year product warranty for their Powerwall. You can review and compare Tesla's Powerwall in the EnergySage Buyer's Guide.

You'll also notice that many battery warranties will include a clause suggesting that your term may be cut short depending on how you use the battery – this is where cycles and throughput come into play.

Cycles

Every time you drain and charge your battery, it's called a "cycle." Like the battery inside your cell phone, your solar battery will gradually lose its ability to hold a full charge the more you use it. Because of this, some manufacturers guarantee a minimum number of cycles as part of their warranty agreement. But read this line carefully: oftentimes, manufacturers will guarantee a fixed product term OR a minimum number of cycles, whichever comes first, the same that a car may be warrantied for either ten years or 100,000 miles. This means if you hit the warrantied number of cycles before your battery hits the end of its warranty period, it could end your warranty term. The confusing part here is that manufacturers will sometimes define a "cycle" differently–i.e., how much your battery needs to be drained and charged for it to be considered a "cycle"?

Tesla doesn't include a cycle clause in their warranty, so you aren't limited to a certain number of cycles throughout the Powerwall's lifetime in order to still be covered by the warranty.

Throughput

Another clause that some manufacturers will put on their warranty pertains to throughput: the total energy a manufacturer expects the battery to deliver throughout its lifetime. Companies state these warranties in terms of megawatt-hours (MWh). For example, if your battery company provides a throughput warranty of 30 MWh, this means that the warranty is valid until the battery stores and delivers 30 MWh–or 30,000 kilowatt-hours (kWh)–of energy. Similar to a cycle life warranty, throughput warranties typically only apply if your battery delivers a set amount of energy before its warranty period is up.

Throughput numbers will vary quite a bit depending on the overall storage capacity of your system. Additionally, if your battery system contains several different battery cells–or modules–within it, your warranty may state a throughput by cell (which you can multiply by number of cells to get the total throughput).

For residential purposes–i.e., if you're using your Powerwall for self-consumption, time-based control, and/or backup–Tesla does not include a throughput warranty. However, for commercial purposes, Tesla includes a throughput warranty of 37.8 MWh for their Powerwall, but this doesn't apply to most homeowners.

In addition to providing cycle or throughput warranties, most manufacturers also promise a certain level of performance by the time your warranty is up. This is often presented as an end-of-warranty capacity rating.

As you're comparing the end-of-warranty capacity ratings across various batteries, higher percentages are better than lower percentage guarantees.

Tesla includes an end-of-capacity rating of 70% for all of their batteries. This means that by the end of your warranty, your battery should still have 13.5 kWh * 0.7 = 9.45 kWh of capacity.

Battery companies should cover a replacement battery if you need it during their warrantied term–but while the manufacturer may cover your replacement part, that doesn't necessarily mean they'll cover the labor costs to re-install that equipment. In fact, many manufacturers do not reimburse for labor associated with diagnostics, replacements, or repairs of their products.

More often than not, installers are the sole party responsible for providing workmanship–or labor–warranties for your battery installation. However, some manufacturers offer additional protection by tacking on their own workmanship warranty for a limited number of certified installers in their network. Tesla's four-year workmanship warranty is available regardless of who installs the Powerwall.

You can learn more about manufacturer endorsements and how they impact installer warranty offerings in this article.

Ideally, your storage system will continue operating smoothly for 10+ years, and you never have to worry about Tesla's warranty. However, if you experience any defects or performance issues with your equipment, Tesla will be there to help.

If you notice an issue with your battery, your first phone call should be to your original installer: having designed and installed your system, they are the most equipped to diagnose (and fix!) any potential issue.

You can also contact Tesla directly about any issues with your battery. They offer 24/7 support for problems relating to their Powerwall and can provide troubleshooting tips or recommend a different Tesla-certified installer to work with. If your Powerwall or parts of your Powerwall needed to be replaced, then Tesla would also cover shipping and labor necessary to get the equipment to you. However, most problems with the Powerwall are due to software issues, so replacement of physical parts is unlikely.

Every warranty has its exceptions – Tesla's is no different. Warranty limitations aren't meant to make it harder for you to take advantage of the offering; companies simply try to protect themselves from unjust or unreasonable claims.

Here are some additional considerations about Tesla's warranty:

• Transferability: Tesla will honor their warranty for any subsequent owner after the original owner as long as they can provide proof of ownership.

• Installer endorsement: Tesla will honor their warranty no matter who installs the solar system. However, they will not honor the warranty if the Powerwall has been tampered with by anyone outside of Tesla-certified installers. They will also not honor the warranty if it has unapproved maintenance of the Powerwall outside of specifications from the user manual.

• Outdoors vs. indoors installation: Tesla will honor their warranty regardless of if the installation is inside or outside. However, they will not honor their warranty if the Powerwall is placed in a location where the temperature range frequently exceeds that of what is recommended in their user manual.

• Proximity to the water: Tesla will void their warranty if the Powerwall is installed in a location subject to flooding or near any water sources such as faucets or sprinklers.

• Acts of nature: Most battery system manufacturers, including Tesla, will not cover any damage caused by extreme weather events outside of their control, such as hurricanes, floods, earthquakes, etc. Fortunately, the hardware is pretty durable and can withstand most storms without the added protection. Even better, should damage happen to occur during a storm, many homeowner insurance policies cover damage to solar-plus-storage systems.

• Bankability: Tesla is one of the largest and most diverse companies in the solar industry, and they will back up their warranty no matter who installs their battery.

• Escrows/insurance policies: Tesla does not have escrow policies for their warranty offering. This means that if Tesla were to go out of business, they may not be able to honor their warranty.

• Customer reviews: A critical aspect of understanding a solar company's warranty offering is investigating how their customers feel about their equipment and the services that they provide. Any warranty can look promising on paper, but how the installer or solar company performs when honoring their warranty is also critically important. If you are interested in reading Tesla's reviews, you can do so here.

Finding the right storage system for your home means comparing multiple quotes from solar installers. Using the EnergySage Marketplace, you can find local solar installers near you and make easy side-by-side comparisons of all your solar-plus-storage options, including equipment. By shopping around first, you can find the right option at the right price – warranties and all. If you have a preference for one type of equipment over another–Tesla or otherwise–simply note it in your account when you sign up so installers can quote you accordingly.