top of page

A Review of the SunVault ESS

Introducing Energy Storage Systems (ESS)

Batteries have been in use for a rather long time both in standalone off-grid setups and in backup power systems. In recent years, however, there has been a significant surge in the popularity of domestic energy storage systems. One of the main drivers behind this trend is the desire for energy security.

Lithium-ion batteries, now recently being offered as 'energy storage systems' or ESS, that is, with advanced features and supporting components that may or may not include a hybrid inverter, MPPT capabilities and a battery management unit, and in 'modular' designs that make them easy to install and used as plug-and-play devices, have grown in popularity over the years. One of the many reasons for this includes the increase in research efforts. For instance, the 2019 Nobel Prize in Physics was awarded for research in Lithium-ion battery technology. Also, the success of the Powerwall and the electric vehicle industry has had a profound effect on the ESS market especially. While lithium-based battery cell technologies are still the costliest of the existing battery technologies, production costs are being driven down by optimal manufacturing processes to meet the boom in demand and more competition that has driven major players in the solar industry into the energy storage segment of the market.

Manufacturer's Profile

SunPower Corporation is an American company that specializes in the design and manufacture of solar modules. It is owned by TotalEnergies. The initial technology and ideas that led to the creation of SunPower were incubated in the research lab of a Stanford University electrical engineering professor. On April 24, 1985, the company was officially incorporated by its founders Richard Swanson and Richard (Dick) Crane as EOS Electric Power. Three years later, the two founders were joined by a third and the company became SunPower. SunPower makes what are by the consensus of industry professionals, the crown jewel of solar panels.

SunPower entered the energy storage market in 2019, with the launch of their first home solar battery: the Equinox Storage system which was later rebranded as the SunVault Storage system. In September 2022, it launched two more variants of the SunVault battery.

General Features

Cell Technology

The SunPower SunVault battery uses Lithium Ferrous Phosphate (LFP) battery chemistry. LFP batteries are known for their long lifespan, safety, and reliability. They are also less likely to overheat than other types of lithium batteries.


The SunVault battery has a depth of discharge (DoD) of 92%. This means that you can use up to 92% of the battery's stored energy before it needs to be recharged. The battery also has a high round-trip efficiency of 86%. This means that 86% of the energy that is used to charge the battery is available for use when the battery is discharged.

IP54 Rating

The SunVault battery has an IP54 rating. This means that it is dust-tight and protected against water jets from all directions and can thus be installed outdoors though a containment cabinet, however, is required for outdoor installation.


The SunVault incorporates a solar inverter that charges the batteries through the solar panels. They are designed solely for backup and off-grid functionality and are cannot be tied to the grid. The SunVault was designed with partial- and whole-home backup in mind. A single SunVault unit is best for partial-home backup, while a double unit is the better option if you're looking for whole-home backup.

Double-Module Design

The SunVault is sold as either a single unit or double unit. A single SunVault unit can hold 13 kWh or 19.5 kWh, and a double SunVault unit holds between 26 kWh and 39 kWh. Capacity is installed in the form of individual 6.5 kWh battery modules that are placed within a larger enclosure.


The SunVault battery can be used with a variety of solar panels and home energy management systems.

Wall-Mountable Design

The physical battery unit is designed to be wall-mounted and to integrate into interior designs, ensuring it remains unobtrusive and space-efficient in your home.

LED Panel

They incorporate LED panels that provides up-to-date information about system status, performance, charge levels, energy use and in-app alerts.

The Hub+

The Hub+ is the control unit for the SunVault battery system. It allows users to monitor the performance of their battery system and manage its settings. Users can also use the Hub+ to connect their battery system to a solar panel system or a home energy management system.

Continuous Power Rating

The SunVault battery has a rather large continuous power rating of 6.8 kW. This means that it will be able to power a large number of appliances during a blackout.

The SV-BASE13-C and SV-BASE19.5-C. Source: SunPower
The SV-BASE13-C and SV-BASE19.5-C. Source: SunPower

SunVault is available in five configurations: 13 kWh, 19.5 kWh, 26 kWh, 39 kWh and 52 kWh. The batteries rated 13 kWh or 26 kWh, both have a power rating of 6.8 kW. These batteries are known as the SunVault Storage 13 and the SunVault Storage 26, respectively.

The two new batteries, called SV-BASE13-C and SV-BASE19.5-C. Some of them incorporate include multiple inverters. The SV-BASE13-C storage system has a storage capacity of 13 kWh and maximum usable energy of 12 kWh. And the SV-BASE19.5-C battery features a storage capacity of 19.5 kWh and maximum usable energy of 18 kWh. Both has the same size.


SunPower offers a standard 10-year warranty on the SunVault. While The warranty includes either 4,000 cycles or 38 MWh energy throughput for the SunVault Storage 13, or 4,000 cycles or 76 MWh energy throughput for the SunVault Storage 26. SunPower guarantees that the battery will retain at least 70%of its initial capacity at the end of the 10-year warranty period. The newer 13 and 19.5 kWh SunVaults come with an unlimited-cycle warranty. This means that there's no limit to how many times owners can use the batteries. Only SunVault and Tesla Powerwall are the only solar batteries with unlimited cycle coverage.

SunPower makes the best solar panels in the market. At least, they once did. The SunVault cannot be said to be the best among energy storage systems. At 86% round trip efficiency rate and 92% DoD, they are still some distance away from the best, the Powerwall. It is also priced well above the average. Regardless, in terms of sophistication and durability as well as its warranty offering, the SunVault compares favourably with the best ESS in the market. SunPower is not widely available in Nigeria but they are highly regarded in the North American markets.


Recent Posts

See All


bottom of page