Panasonic EverVolt: The complete home battery review

Panasonic is one of the world's largest battery cell manufacturers, and they made their foray into the energy storage industry in 2019 when they launched their residential battery storage product: the EverVolt. A scalable storage system with both AC and DC-coupled configurations, the EverVolt can provide plenty of backup energy for your home in the event of a grid outage, especially when you pair it with a solar panel system. In November 2021, Panasonic announced a new addition to its battery lineup: the EverVolt 2.0. While Panasonic will continue to sell models of the original EverVolt, the EverVolt 2.0 comes with new features, including different lithium-ion battery chemistry, larger available sizes, and an outdoor rating.

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The Panasonic EverVolt 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. Installing a storage solution like the EverVolt or EverVolt 2.0 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 EverVolt and EverVolt 2.0 are both sized for day-to-day use at your home and are primarily designed to accompany 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 buying it from your utility company.

The EverVolt and Evervolt 2.0 are specifically designed to pair with Panasonic's premium HIT panels. With the HIT modules' built-in Enphase microinverters, you can create a complete solar plus storage home setup, all under warranty by the same company.

There are a few key differences between Panasonic's original EverVolt and the EverVolt 2.0. While we'll go into more detail in the sections below, the following table summarizes these differences. 

Panasonic EverVolt vs. EverVolt 2.0 specs

The EverVolt is one of a handful of batteries available in almost identical AC and DC versions. It can be just as easily installed alongside a new solar panel system as it can be added as a retrofit to an existing system.

When you're evaluating the EverVolt and EverVolt 2.0, there are various important metrics and technical specifications to look out for. Among the most important are the size of the battery (power and capacity), its chemistry, depth of discharge, and roundtrip efficiency. 

Size

The original Panasonic EverVolt comes in four models: two AC coupled (EVAC-105-4 and EVAC-105-6) and two DC coupled (EVDC-105-4 and EVDC-105-6). The AC and DC coupled models are essentially the same as far as performance metrics, except for roundtrip efficiency. We'll refer to them both by their designations as "Standard" and "Plus" to include both the AC and DC-coupled versions of the same batteries. The EverVolt 2.0 comes in two different models: EVHB-L6 and EVHB-L9. 

Power (measured in kilowatts, or kW) can be defined in two ways: peak (maximum) and continuous. Peak or maximum power refers to the maximum amount of electricity that can be output at a single time, while continuous power is the maximum amount of electricity that can be output consistently. Usable capacity (measured in kilowatt-hours, or kWh) measures the maximum amount of electricity stored in your battery on a full charge. For the original EverVolt, the larger Plus model boasts a power rating of 5.5 kW, with 17.1 kWh of usable capacity. The Standard model offers 4.6 kW of power and 11.4 kWh of usable capacity. For the EverVolt 2.0, Panasonic has only announced the continuous power, with both models having an on-grid power rating of 9.6 kW and an off-grid power rating of 7.6 kW. The EVHB-L6 and EVHB-L9 have usable capacities of 17.1 kWh and 25.65 kWh, respectively. 

The Panasonic EverVolt systems are also modular, meaning you can stack multiple battery systems together if you want an even larger backup capacity. You can connect up to two original EverVolt Plus model batteries to a single EverVolt inverter, so you'll need to upgrade your supporting hardware to add additional storage capacity beyond the stored energy of two batteries. You can also stack up to three EverVolt 2.0 systems together for an overall maximum usable capacity of up to 76.9 kWh. 

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 suite of EverVolt products is designed to provide both of these services. In addition, the EverVolt 2.0 offers many different functionalities, depending on what you need from your battery system. You can switch the operating mode of your EverVolt 2.0 from back-up to residential to time-of-use to a custom mode of your choice. Like many other battery companies, Panasonic provides a companion app for their energy products. With their EverVolt software and a solar plus storage system, you can view real-time energy usage and solar electricity generation. 

Serviceability

While solar batteries are highly reliable and rarely require maintenance, some are easier to service than others. In general, modular batteries are easier for installers to service in the field – meaning you likely won't have to ship the whole battery back to the manufacturer for maintenance. The EverVolt and Evervolt 2.0 are modular batteries, and Panasonic states explicitly that it's designed for field serviceability, giving you peace of mind that your battery can be easily fixed if you experience any issues. 

Chemistry

The EverVolt is a lithium nickel manganese cobalt oxide (NMC) battery, while the EverVolt 2.0 is a lithium iron phosphate (LFP) battery, also known as a lithium-ion storage product. LFP batteries are one of the most common lithium-ion battery technologies and for a good reason. 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.

Outdoor rating

If you're hoping to install your solar battery outside, you'll need to ensure it's weatherproof and has an outdoor protection rating. While you can only install the original EverVolt indoors, the EverVolt 2.0 is weatherproof and outdoor-rated. 

Inverter

Inverters are necessary to convert electricity from direct current (DC), which is generated by solar panels and stored in solar batteries, to alternating current (AC), which is used by most household appliances. Storage systems can come with or without an integrated inverter – if your system doesn't come with an integrated inverter, you'll have to pair it with a separate, external inverter. 

If your system comes with a hybrid inverter, it can cover the production from your solar panels as well as the requirements of your storage system. Storage systems can also be either AC- or DC-coupled. While AC-coupled systems are generally easier to install if you're retrofitting your storage system to an existing solar system, DC-coupled systems typically provide higher overall efficiency. The original EverVolt has different inverters for AC and DC systems. On the other hand, the EverVolt 2.0 comes with a built-in hybrid inverter that can be either AC- or DC-coupled (for systems with up to 12 kW solar), giving you flexibility in your system setup. It also comes with four built-in maximum power point tracking (MPPT) charge controllers, which prevent the battery from overcharging while delivering the maximum power possible from your solar array. The original EverVolt does not come with a built-in MPPT. 

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 manufacturers specify a maximum DoD level for optimal battery performance. Generally, batteries with a higher depth of discharge are considered higher-quality products. The Panasonic EverVolt doesn't list a depth of discharge on its spec sheet, but the EverVolt 2.0 boasts an impressive DoD of 100 percent. 

Roundtrip efficiency is a measure of electrical losses involved with charging and discharging a particular battery. The higher the percentage, the more efficiently the battery can convert incoming electricity into stored electricity and back into usable electricity. Both the EverVolt and EverVolt 2.0 have a roundtrip efficiency of 90 percent; this means that for every 10 kilowatt-hours (kWh) of electricity, you put into the battery, you'll receive 9 kWh of output. 

Panasonic states that the EverVolt battery line is backed by a 10-year product and performance warranty as long as a Certified EverVolt Installer installs it. This warranty will cover the battery modules, the inverters, all internal components, and the cabinets and enclosures. 

For the original Evervolt, the warranty coverage says that by the end of 10 years, your EverVolt will still be able to store at least 60 percent of its initial out-of-box capacity. Panasonic also offers an energy throughput warranty – the 60 percent retained capacity after 10 years is only valid if the total energy throughput over the 10-year period is less than 7.56 megawatt-hours (MWh) per battery module. Summed up, your EverVolt Standard model battery is warrantied to retain at least 60 percent of its capacity by the time you hit a lifetime of 10 years or an energy throughput of 30.2 MWh, and your EverVolt Plus model battery is warrantied to retain at least 60 percent of its capacity by the time you hit a lifetime of 10 years or an energy throughput of 45.3 MWh, whichever happens first.

The EverVolt 2.0 warranty comes with a clause of 6,000 cycles – meaning if you exceed 6,000 cycles before 10 years, your warranty will no longer be applicable. The warranty also states that at the end of 10 years, your system can still store at least 60 percent of its initial out-of-box capacity.

Panasonic's battery technology is similar to other large and small rechargeable batteries. As time passes, the battery will lose 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, over time, it will start to feel like your phone battery doesn't last as long as it did when it was new.

The battery life of your EverVolt batteries 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 after extended usage, whether it's an electric vehicle battery, a home energy battery, or a rechargeable AA battery. This is why Panasonic offers a warranty guaranteeing a certain percentage 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.

A solar battery installation isn't as simple as a list price for a component – depending on your electrical setup, among other factors, installation costs can vary widely. Panasonic has not yet announced costs for the EverVolt 2.0, but an installation of the original EverVolt generally ranges from $15,000 to $20,000 depending on if you choose the Standard or Plus model.

If you want to install the EverVolt or EverVolt 2.0 as part of a solar-plus-storage system, battery costs are just one part of the equation. A 5 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 EverVolt or EverVolt 2.0 makes sense for you is determined by how your electric utility structures its rates and 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 (such as Massachusetts) are also in the early stages of evaluating battery storage performance incentives, and several states already provide cash rebates. You may also be able to participate in a virtual power plant (VPP) aggregation program, in which you get paid to help stabilize the grid – in fact, the EverVolt 2.0 has hardware for future integrations with VPP providers and aggregators.

Installing a solar-plus-storage system at your home is a great way to take control of your electric 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 EverVolt and EverVolt 2.0, only have enough capacity to store a few hours of electricity. That said, the EverVolt and EverVolt 2.0 could serve as a temporary backup if you have a solar panel system to provide power when the grid goes down.

Whether you want to install the original EverVolt, EverVolt 2.0, or another solar battery, 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 Panasonic EverVolt, EverVolt 2.0, and other energy storage options available. 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.