Sonnen eco: The complete battery review

sonnen is one of the biggest names in energy storage technology. Their product line includes three different models: the sonnen eco, the sonnenCore, and the ecoLinx battery. The eco is a fully integrated energy storage system that includes an inverter and smart energy management software. The sonnenCore is also a fully integrated energy storage system with an inverter and management software, but it operates at a more compact size than previous products from the company. The ecoLinx is sonnen's "luxury" battery offering and syncs your entire property's energy usage together to efficiently and intelligently manage how you use energy in your home. Property owners with solar that install a home battery like these can store excess solar electricity for use later in the day. As a result, a solar-plus-storage installation can increase your total monthly savings in certain markets.

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The sonnen eco, sonnenCore, and ecoLinx batteries are ideal pairings for solar panel systems, especially if your utility has reduced or removed net metering, time-of-use rates, or demand charges. Installing an energy storage solution like the sonnen eco, sonnenCore, or ecoLinx allows you to maintain a sustained power supply during the day or night as long as you store enough power from your solar panels when the sun is shining.

As with other energy storage products, these batteries are sized for day-to-day use at your home, and they're often paired with a home solar panel system. When your solar panels produce more electricity than you can use in your home, the excess is stored in the battery system instead of being sent back into the grid. When your panels aren't producing enough electricity to meet your home's needs, you can use the electricity stored in your sonnen home battery instead of having to buy it from your utility company.

sonnen describes the eco battery as an "all-in-one residential solar battery solution." It offers various grid-tied functions, including increasing household solar self-consumption and managing time-of-use electricity rates for maximum savings on your electricity bill. The battery also has some backup power capabilities.

Among the most important considerations when you're comparing solar batteries are the size of the battery (power and capacity), its chemistry, depth of discharge, and roundtrip efficiency. 

Size

The sonnen eco comes in seven different sizes with varying power and usable capacities. Power (measured in kilowatts, or kW) determines the maximum amount of electricity a battery can output at a single time, while usable capacity (measured in kilowatt-hours, or kWh) is a measure of the maximum amount of electricity from your battery on a full charge.

Think of your battery like water running through a pipe. 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 available energy capacity faster too.

sonnen eco power and usable capacity by model

A battery's power determines what appliances you can run with it at once, while usable capacity determines how long those appliances can be run. Batteries with a higher power rating are capable of powering more robust appliances or many appliances at once, while batteries with a higher usable capacity can store 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 boast of superior off-grid capabilities, while others offer software solutions for rate arbitrage. Here are some of the most important qualities of the sonnen eco:

Coupling

The sonnen eco is an AC-coupled battery; this means that in a solar plus storage system, direct current (DC) electricity flows from solar panels to a solar inverter that transforms the electricity into alternating current (AC) electricity. That AC electricity can then flow to your home appliances or go to another inverter that transforms the electricity back to DC for storing in a battery system.

Backup power

The sonnen eco comes with backup power capabilities. Most solar batteries require an external transfer switch to allow for off-grid operation, but the sonnen eco has a built-in automatic transfer switch. This means that with the correct power electronics set up, your sonnen ecosystem can automatically power your home appliances when the grid goes down.

Chemistry

The sonnen eco is a lithium-ion storage product, specifically, it's a lithium iron phosphate (LFP) battery. Relative to other types of batteries, LFP batteries are known for their high power rating and safety – to learn more about how different lithium-ion battery chemistries stack up against one another, check out our overview of battery chemistry differences.

Performance metrics

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

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 it, many battery manufacturers specify a maximum DoD level for optimal battery performance. In general, batteries with a higher depth of discharge are considered higher-quality products. The sonnen eco line boasts a depth of discharge of 100 percent across all battery sizes.

Roundtrip efficiency is a measure of the electrical losses involved with charging and discharging a particular battery. The higher the percentage, the more efficiently the battery is able to convert incoming electricity into stored electricity and then back into usable electricity. All batteries in the sonnen eco line have a roundtrip efficiency of 81.6 percent; this means that for every 10 kilowatt-hours (kWh) of electricity you put into the battery, you'll receive 8.16 kWh of output.

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 an 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.

Size

The sonnenCore comes in one size currently, available in both AC or DC configurations. The sonnenCore boasts a maximum power rating of 8.6 kW to go along with 10 kWh of usable capacity.

Basic functionality

The sonnenCore is designed to provide both excellent off-grid capabilities and software solutions specific to rate arbitrage.

Performance metrics

The sonnenCore has a roundtrip efficiency of 85%; this means that for every 10 kilowatt-hours (kWh) of electricity, you put into the battery, you'll receive 8.5 kWh of output. The sonnenCore boasts an excellent depth of discharge of 100%.

sonnen's website states that the ecoLinx "…merges clean-tech with high-tech, giving you the ultimate smart home powered by clean energy." Perhaps more so than many other energy storage options, the ecoLinx can intelligently pair with home automation setups to manage what appliances consume power and when they consume power so that you can save money and have peace of mind. The ecoLinx can preemptively store extra energy if there's severe weather headed your way, or it can turn off non-critical appliances and electrical loads when you don't use them. It can also do the more typical home battery job of smart load management by reducing your reliance on the electric grid automatically during peak demand times, when prices may be higher in certain parts of the country.

The ecoLinx can integrate with many leading home automation platforms, as well as popular products like Nest thermostats or the Lumin Smart Panel.

Size

The sonnen ecoLinx comes in two different models: the ecoLinx and the ecoLinx 30. While the ecoLinx30 comes in only one size, the ecoLinx series includes five different size options (12, 14, 16, 18, and 20 kWh). According to their datasheets, the sonnen ecoLinx line has a power rating of 8 kW. The ecoLinx 30, the largest battery in the lineup, boasts 30 kWh of usable capacity, while the smaller ecoLinx comes in 2 kWh size increments from 12 kWh to 20 kWh capacity.

Basic functionality

Similar to the sonnenCore, the suite of ecoLinx hardware and software products is designed to provide both excellent off-grid capabilities and software solutions specific to rate arbitrage.

sonnen offers a storage inverter alongside their ecoLinx that converts excess AC electricity produced by a solar array into DC electricity to store in the ecoLinx. This means that as long as your installer installs the correct components and the ecoLinx inverter, your sonnen ecoLinx battery will be able to provide backup power and continue to interact with your solar panel system when the grid goes down.

Performance metrics

The sonnen ecoLinx line boasts a depth of discharge of 100 percent. It has a high roundtrip efficiency of 81.6 percent; this means that for every 10 kilowatt-hours (kWh) of electricity you put into the battery, you'll receive 8.16 kWh of output.

In most cases, homes with a sonnen battery will charge and drain the battery every day. The eco comes with a 10-year, or 10,000-cycle, warranty. sonnen guarantees that the battery will maintain at least 70 percent of its capacity to hold a charge during that time.

sonnen 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 capacity.

The battery life of your eco 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.

The sonnenCore battery line is also 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.

The ecoLinx comes with a 15-year/15,000-cycle limited warranty. This means that an ecoLinx warranty is valid for either 15 years or the amount of time it takes to cycle the battery (charge and discharge) 15,000 times, whichever comes first.

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. The sonnen eco has a starting list price of around $10,000, which includes an integrated inverter and energy management software. Note that the price doesn't include installation, which can increase your costs by thousands of dollars.

According to sonnen, the sonnenCore starts at $9,500. 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.

While sonnen says pricing for the ecoLinx varies from installation to installation, list prices for the 12 kWh ecoLinx product online are around $36,000. For larger models, this price will only go up. If you want to install any of these batteries as part of a solar-plus-storage system, battery costs are just one part of the equation. An average 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 sonnen eco, sonnenCore, or ecoLinx 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.

Depending on where you live, you may have access to financial incentives that can reduce your home energy storage installation costs. 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 (like Massachusetts) are in the early stages of evaluating potential energy storage performance incentives as well, and several states already provide cash rebates.

sonnen's eco battery is currently available through the company's installer network in the U.S. 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. The sonnen ecoLinx battery is available online through sonnen's website, where you can request a quote. Whether you want to install a sonnen eco, sonnenCore, or ecoLinx, you will most likely need to work through a certified installer. Adding energy storage technology to your home is a complicated process that requires 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 sonnen home battery and other energy storage options available to homeowners today. If you're interested in receiving competing installation quotes for solar and energy storage options from local installers near you, simply join the EnergySage Marketplace today and indicate what products you're interested in your profile's preferences section.