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The sonnenCore complete review

sonnen is one of the biggest names in energy storage. Their product line now includes three different models: the familiar sonnen eco, the ecoLinx, and now, their new sonnenCore battery. The sonnenCore is a fully integrated energy storage system that includes an inverter and smart energy management software, at a more compact size than previous products from the company. Property owners with solar that install a home battery like the sonnenCore are able to store excess solar electricity for use later in the day. As a result, properties with solar-plus-storage can increase their total monthly savings in certain markets.

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. Find out what solar + storage costs in your area in 2023

Key takeaways

  1. The sonnenCore battery starts at a price of $9,500 before installation.

  2. You may need several sonnenCore batteries in order to truly go “off the grid”.

  3. A qualified EnergySage-approved installer can give you the best information about the sonnenCore home battery system and other energy storage options available to homeowners today.

How does the sonnenCore work?

The sonnenCore pairs well with solar panel systems, especially if your utility has reduced or removed net metering, introduced time-of-use rates, or instituted demand charges for residential electricity consumers. Installing a storage solution like the sonnenCore with a solar energy system allows you to maintain a sustained power supply during both day and night, as long as you store enough power from your solar panels when the sun is shining.

As with many other home battery products, the sonnenCore is sized for day-to-day use at your home and is primarily designed to be paired with a solar panel system. When your solar panels produce more electricity than you can use in your home, you can store the excess electricity in the battery system instead of sending it back into the grid. Later, when your panels aren’t producing enough electricity to meet your home’s needs, you can use the stored energy in your battery instead of having to buy it from your utility company.

Key things to know about the sonnenCore

According to sonnen, “The sonnenCore is an intelligent energy storage solution that combines smart energy management software with safe, long-lasting and cobalt-free batteries to efficiently manage energy usage throughout the day, store excess solar power for use at night and provide reliable emergency backup power to keep homes protected during grid outages.”

The sonnenCore is more compact than any battery sonnen has launched before. It is a Lithium Iron Phosphate (LFP) battery (as opposed to the traditional Lithium-Ion NMC technology many batteries utilize), which can offer longer life, improved reliability, and increased safety compared to more traditional lithium-ion battery technologies. With their companion computer or phone apps and a solar-plus-storage system, you can view real-time energy usage and solar electricity generation from wherever, at any time.

When evaluating the sonnenCore, there are various important metrics and technical specifications to keep in mind. Among the most important are the size of the battery (power and capacity), its depth of discharge, and roundtrip efficiency.


The sonnenCore comes in one size currently, available in both AC or DC configurations. Two important metrics to keep in mind when comparing the sonnenCore to other home storage options are power and usable capacity. Power (measured in kilowatts, or kW) determines the maximum amount of electricity that can be output at a single time, while usable capacity (measured in kilowatt-hours, or kWh) is a measure of the maximum amount of electricity stored in your battery on a full charge. The sonnenCore boasts a maximum power rating of 8.6 kW to go along with 10 kWh of usable capacity.

Think of your battery like water running through a pipe. The usable energy capacity is the amount of water available to push through the pipe, while power is the size of the pipe itself. Larger pipes allow more water to flow through at once, which depletes the water faster. Similarly, a battery with a high power rating can deliver more electricity at one time, but will burn through its stored energy faster too.

A battery’s power determines the number of appliances you can run from the battery concurrently, while usable capacity determines how long those appliances can be run. Batteries with a higher power rating are capable of powering more, bigger appliances (i.e., your HVAC system) or many appliances at once, while batteries with a higher usable capacity can store more total energy and thus can run your appliances for longer periods of time without needing to recharge.

Basic functionality

The functionality of one solar battery next to another can vary; some batteries have excellent off-grid capabilities, while others offer software solutions specific to rate arbitrage. The sonnenCore is designed to provide both of these services.

Performance metrics

Two key ways to evaluate the performance of a solar battery are its roundtrip efficiency and depth of discharge.

Roundtrip efficiency is a measure of electrical losses involved with charging and discharging a battery. The higher the efficiency percentage, the more efficiently the battery is able to convert incoming electricity into stored electricity and then back into usable electricity. The sonnenCore has a roundtrip efficiency of > 85 percent; this means that for every 10 kilowatt-hours (kWh) of electricity you put into the battery, you’ll receive a little more than 8.5 kWh of output.

Depth of discharge (DoD) indicates the percentage of a battery’s energy that has been discharged relative to the overall capacity of the battery. Because the useful life of a battery decreases each time you charge, discharge, and re-charge–or cycle–your battery, many battery manufacturers specify a maximum DoD level for optimal battery performance. In general, batteries with a higher depth of discharge are considered better quality products. The sonnenCore boasts an excellent depth of discharge of 100%.

sonnenCore warranty coverage

sonnenCore warranties

  1. Warranty period: 10 years

  2. Warrantied cycles: 10,000

  3. Guaranteed end-of-warranty capacity: 70%

The sonnenCore battery line is backed by a 10-year, or 10,000 cycle, product and performance warranties that cover the equipment in the case of faulty parts or defects, as well as the actual performance of the battery. sonnen’s warranty coverage says that by the end of 10 years or cycling your battery 10,000 times, your sonnenCore will still be able to store at least 70 percent of its initial out-of-box capacity.

Importantly, sonnen’s battery technology is similar to other rechargeable batteries both large and small: as time goes on, the battery loses some of its ability to hold a charge. Think of how the battery life of a brand-new smartphone compares to one that is a few years old. As you continually charge and drain your phone’s battery, it starts to lose some of its ability to hold a charge.

The battery life of your sonnenCore battery will deteriorate in the same way. That isn’t an indicator of a product flaw – all batteries lose some of their ability to hold a charge over time, whether it’s an electric vehicle battery, a home energy battery, or a rechargeable AA battery. This is why sonnen offers a warranty that guarantees a certain amount of storage capacity.

If you want to compare individual battery models side-by-side, our battery Buyer’s Guide lets you select products and compare them based on efficiency, capacity, power, and more.

How much does the sonnenCore cost?

The cost of installing a battery isn’t as straightforward as looking up the list price for an individual component–i.e., your battery. In fact, depending on your electrical setup, installation costs can vary widely. According to sonnen, the sonnenCore starts at $9,500. Importantly, this is just the cost for the battery itself. Depending on the complexity of your installation, the company you work with, and whether or not you add a solar panel system with your battery, the actual cost to install a sonnenCore will increase by a certain amount.

For example – if you want to install the sonnenCore as part of a solar-plus-storage system, solar costs need to be factored in as well. A 5 kilowatt (kW) solar energy system costs anywhere from $9,000 to $15,000 depending on where you live and the type of equipment you choose.

That may sound like a lot of money, but installing a solar-plus-storage system can be a worthwhile investment. Whether or not the sonnenCore makes sense for you is determined by the way that your electric utility structures its rates, as well as your reasons for installing a solar battery.

In some cases, depending on where you live, you may have access to financial incentives that can reduce your home energy storage installation costs. For instance, if you live in California, you could get a cash rebate that covers most of your home battery costs through the Self-Generation Incentive Program (SGIP). Other states (such as Massachusetts) are in the early stages of evaluating battery storage performance incentives as well, and several states already provide cash rebates.

Can you go off-grid with the sonnenCore?

Installing a solar-plus-storage system at your home is a great way to take control of your electricity bill, but it doesn’t mean that you’re completely disconnected from your utility. Going “off the grid” with solar batteries is actually a more expensive and complicated proposition than you might think. Most home batteries, including the sonnenCore, only have enough capacity to store a few hours of electricity. If you want to make sure you can maintain power to your property for days at a time, you’ll need to install several sonnenCore batteries together to increase your storage capabilities.

Where to buy the sonnenCore

You can find an installer for a sonnenCore directly through sonnen’s website, or from local solar installers and/or installation companies that carry the sonnenCore. Adding energy storage technology to your home is a complicated process that needs electrical expertise, certifications, and knowledge of the best practices required to install a solar-plus-storage system correctly.

A qualified EnergySage-approved company can give you the best recommendation about the sonnenCore home battery system and other energy storage options available to homeowners today. If you are interested in receiving competing installation quotes for solar and energy storage options from local installers near you, simply join the EnergySage Solar Marketplace today and indicate what products you’re interested in your profile’s preferences section.

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