A Technical Review Of The SunPower SunVault Storage Solution

The SunPower SunVault battery storage solution allows you to gain more control over your home energy usage and protect against power outages, blackouts and more. By storing excess solar power during the day for use at night or during peak hours, the home battery can also act as a backup power source in case of an outage or other emergency.

With the recent passage of the Inflation Reduction Act, many homeowners are interested in pairing a SunVault home battery with SunPower solar panels. While there are many great reasons to add solar + battery storage to your home, it’s important to learn more about the SunVault beforehand.

Key Things to Know About SunPower’s SunVault System

If you’re interested SunPower’s SunVault battery storage solution as well as its technical details, here’s some important things to know:

SunVault Home Battery Specifications

  • Power rating: 6.8 kW
  • Rated energy capacity: 13 kWh per battery
  • Dimensions: 26 x 63 x 15
  • Cost : $12,000 – $25,000
  • Warranty: 10-year limited warranty


The SunVault system comes with the battery itself, along with the Hub+, which controls the energy flow and determines how the stored energy is used. An example of this happens when the system detects that there isn’t any energy coming from your solar panels and switches to stored energy from your battery.

Additionally, the SunVault is made with a Lithium Ferrous Phosphate (LFP) battery. In comparison, many traditional batteries were designed with Lithium-Ion NMC technology. SunVault’s physical battery can be wall-mounted, which helps it  keep a low profile and out of the way in your home. The battery’s chemistry also offers a longer life, better reliability and increased safety.


When comparing home battery options, two important metrics to keep in mind are power and usable capacity. Power is measured in kilowatts (kW) and determines the highest amount of electricity your battery can output at once. Usable capacity is measured in kilowatt-hours (kWh) and measures the maximum amount of electricity your battery can store on a full charge.

SunVault’s battery storage system comes in three sizes of usable capacity, all with the same power rating. A higher amount of usable capacity means that you can store more total energy and thus run your appliances for longer periods without the need to recharge your batteries (although this depends on what appliances you’re running). You can get a SunVault system in capacities of 13 kWh or 26 kWh, both with a power rating of 6.8 kW. These batteries are known as the SunVault Storage 13 and SunVault Storage 26, respectively.

Performance Metrics

There are two ways to evaluate a solar home battery’s performance: by its roundtrip efficiency and depth of discharge.

Round-trip efficiency measures how much electricity is lost when a battery is charging and discharging. A higher efficiency percentage indicates the battery can more efficiently convert incoming electricity into stored electricity and then into usable electricity.The SunVault has a round-trip efficiency of 85%. 

Depth of discharge (DoD) is the percentage of a home battery’s energy that’s been discharged compared to the overall battery capacity. The useful life of the battery decreases with every charge, discharge and recharge (or cycle). Generally, batteries with a higher depth of discharge rate are considered to be better quality products. SunPower currently does not disclose the DoD information for the SunVault. 

Continuous Power Rating

The continuous power rating, or power rating, tells you how much electricity a solar battery can release at once for your home appliances to utilize and is measured in kilowatts (kW). A battery’s power rating is important because it lets you know how many appliances you can run at the same time.

The capacity of a battery is like water running through a pipe: it’s the amount of water available to push through the pipe. The power rating is like the size of the pipe itself. A larger pipe allows more water to flow through at once and depletes water at a faster rate. Likewise, batteries with a high power rating can deliver more electricity at one time, but they’ll also burn through its stored energy faster.

The SunVault has an impressive continuous power rating of 6.8 kW, one of the industry’s highest.  Most solar batteries have a power rating around 5 kW, so the SunVault battery is able to power a few more appliances compared to its competitors.

Rated Energy Capacity

A battery’s capacity rating is one of the most important technical details to look for. The SunVault’s rated capacity is 13 kWh, which is the equivalent of roughly half of the average American home’s daily energy usage. The usable capacity of SunPower’s SunVault solution is 12 kWh or 24 kWh. This indicates how much of the total battery capacity is actually available for use once you factor in things like charging efficiency and the amount of electricity you can discharge without damaging the battery.

Most of today’s lithium-ion batteries allow you to use all of the stored energy within the battery, so rated and usable capacities would be the same. 


Thanks to SunPower’s reputation and the quality of its products, its SunVault home battery is no different. It’s a reliable option since it’s built, warrantied and serviced by the same company and provides peace of mind protection when the power goes out.

To determine if a SunVault home battery is right for your home energy needs, our certified Solar Technologies representatives can answer all your questions. If you’re ready to change the way you power your home and start saving more with solar, contact us today for a free customized quote.

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