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We read SunPower’s SunVault battery warranty so you don’t have to 

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 companies, 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. In this article, we take a detailed look at the battery warranty of one of the biggest names in the solar industry: SunPower Find out what solar + storage costs in your area in 2023

Highlights of the SunPower® SunVault™ warranty

  1. Is based on a warranty period of 10 years and unlimited cycles.

  2. Covers replacements and repairs at no cost to you during the warranty period.

  3. If your SunPower affiliated installer goes out of business, SunPower will still honor their workmanship warranty.

Visit the EnergySage Marketplace to compare solar-plus-storage options from local installers.

Quick overview: SunPower’s history and warranty

SunPower’s co-founder, Dr. Richard Swanson, began his research into solar in 1970 as a possible solution to the ongoing oil crisis at that time. Following this research, in 1985 Dr. Swanson founded SunPower with funding from the Department of Energy (DOE), the Electric Power Research Institute, and venture capitalists. Since that time, SunPower has worked to create innovations in the solar industry, with notable achievements including creating the solar panels on NASA’s Pathfinder rover, setting world records in solar panel efficiency, and powering a solar plane on a trip around the world.

SunPower’s warranties are also strong offerings when compared to other installers. SunPower product and labor warranties are all provided by a single company, as only SunPower affiliated installers work with SunPower products. This provides extra security for homeowners because both the labor warranties and battery warranties are backed by SunPower.

SunPower’s battery warranty at a glance CATEGORYSUNPOWER’S COVERAGEINDUSTRY STANDARD Product and performanceSunVault Storage 13 and 26: 10 years, unlimited cycles10 years, plus a cycles or throughput clause End of warranty capacity70% at year 1060% at year 10 Labor for repairs/ replacementsYesNo Shipping of partsYesNo TransferabilityYes, no feeYes, no fee

SunPower’s product and performance warranty

A battery company’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.

SunPower includes a 10-year product warranty for all of their batteries. You can review and compare SunPower’s batteries 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 your use of the battery – this is where cycles and throughput come into play.


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 companies guarantee a minimum number of cycles as part of their warranty agreement. But read this line carefully: oftentimes, companies will guarantee a fixed product term OR a minimum number of cycles, whichever comes first. 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 companies 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”?

SunPowerdefines a “cycle” as the battery being 100% discharged and recharged and includes unlimited cycles for all of their batteries during the warranty period.


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 total throughput).

SunPower includes an unlimited throughput warranty.

SunPower’s end of warranty capacity rating

In addition to providing cycle or throughput warranties, most companies also promise a certain level of performance by the time your warranty is up. This often presents itself 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.

SunPower includes an end of capacity rating of 70% for all of their batteries. You can check the end of warranty capacity ratings for each SunVault model in the table below.

SunPower’s SunVault end of warranty capacity SunVault Storage 13SunVault Storage 26 Initial usable capacity (kWh)12 kWh24 kWh End of warranty capacity (kWh)9.1 kWh18.2 kWh

SunPower’s workmanship warranty

Battery companies should cover a replacement battery if you need it during their warrantied term–but, while the company may cover your replacement part, that doesn’t necessarily mean they’ll cover the labor costs to re-install that equipment. In fact, many companies 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 companies offer additional protection by tacking on their own workmanship warranty for a limited number of certified installers in their network. SunPower does cover labor associated with removal and reinstallation, as long as the work is performed by a SunPower authorized installer.

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

How to make a warranty claim with SunPower: shipping & labor costs

Ideally, your storage system will continue operating smoothly for 10+ years, and you never have to worry about SunPower’s warranty. However, if you experience any defects or performance issues with your equipment, SunPower 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. If you can’t get in touch with your installer, or if they’ve gone out of business, you can contact SunPower to help you.

You can also reach directly out to SunPower during the warranty period if there are issues that the installers cannot address for you. When it comes time for any repairs or replacements, there are two additional warranty considerations you’ll want to keep in mind: labor and shipping costs.

Labor costs for diagnostics, repairs or replacements

Many companies cover replacement parts at no extra cost, but don’t pay for the labor costs necessary to re-install that equipment. SunPower will cover labor costs for removal, repair, and reinstallation; however, they specify that this work must be performed by a SunPower authorized installer.

Shipping of parts

Similarly, not all equipment companies will pay the costs to get equipment to you – but SunPower isn’t one of them! SunPower will cover the shipping costs for any defective parts that need to be returned, and the shipping costs for any replacement or repaired parts required to fix your battery.

Limitations and exceptions to SunPower’s warranty

Every warranty has its exceptions – SunPower’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 a few things that aren’t covered in your SunPower warranty:

  1. SunPower batteries are certified for outdoor use, but the temperature of the location that they are installed cannot fall outside of the range of -4°F to 122°F.

  2. Installation in conditions that are in violation of the SunPower battery installation manual.

  3. Technical or cosmetic defects that do not interfere with the performance of the battery or actively degrade the system.

  4. Acts of nature – this is a common one – most companies that sell battery systems 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.

Other warranty considerations, and how SunPower stacks up

  1. Transferability: the SunPower SunVault warranty is transferable – you just need to be sure to notify SunPower within 90 days of the ownership transfer and they will provide you with the Subsequent Assignee Warranty.

  2. Bankability: SunPower is one of the oldest companies in the solar industry and a publicly traded company (Nasdaq: SPWR) based in San Jose, California. They have been providing solar panels and related products since 1985. If your installer goes out of business, they will send another SunPower certified installer to help with repair and replacement.

  3. Escrows/insurance policies: SunPower does not have any escrow or insurance policies to protect consumers if they go out of business.

  4. Eligibility: some companies require customers to permanently connect to their monitoring system in order for their warranty to be valid. SunPower’s warranty requires the system to remain connected to the Internet for the period of the warranty. You can monitor your system’s connection to the Internet via the SunPower mobile app.

  5. Customer reviews: it is always helpful to hear from other customers when you are trying to get the full picture of a company and how reliable they will be in honoring their warranty. If you’re interested in what other EnergySage customers think about SunPower, you can check out their reviews here.

What about inverters?

We use “battery” and “battery system” pretty interchangeably in this article, but there’s one important difference between the two: an inverter. Energy storage systems typically include both batteries and inverters, while certain batteries can be sold independently. Inverters are key to the functionality of a battery, so it’s important to make sure yours is covered! If your product includes a built-in storage-only or hybrid inverter, it’ll likely be covered in your battery’s warranty terms. On the other hand, if you pair your battery with an external, third-party inverter, expect it to come with a different warranty agreement than your battery.

SunPower’s batteries are all built-in–thus, their warranty covers the inverters.

Finding the right battery for you

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–SunPower or otherwise–simply note it in your account when you sign up so installers can quote you accordingly.


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