In 2019, Panasonic, one of the world’s largest battery cell manufacturers, officially launched their own residential battery storage product: the EverVolt. A scalable storage system with both AC and DC-coupled configurations, the EverVolt can provide plenty of back-up energy for your home in the event of a grid outage, especially when paired with a solar panel system.
How does the Panasonic EverVolt work?
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 consumers. Installing a storage solution like the Panasonic EverVolt 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 Panasonic EverVolt 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.
The EverVolt is 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.
Key things to know about the Panasonic EverVolt
In Panasonic’s own words: “With EverVolt, homeowners will be one step closer to grid independence and see a quicker return on their solar investment. EverVolt users will have the ability to store unused power to use when they need it most or sell surplus energy back to their local utility and generate income.” Uniquely, the EverVolt is available in almost identical AC and DC versions, meaning 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.
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.
When evaluating the EverVolt, 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 Panasonic EverVolt comes in four different models: two AC coupled (model numbers: EVAC-105-4 and EVAC-105-6) and two DC coupled (EVDC-105-4 and EVDC-105-6). Both types of EverVolts are modular, meaning they can be stacked together to create even larger, more powerful battery systems. The AC and DC coupled models are essentially the same as far as performance metrics, with the exception of roundtrip efficiency – so 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.
Two important metrics to keep in mind when comparing the EverVolt 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 larger Plus model boasts a maximum power rating of 5.5 kW to go along with 17.1 kWh of usable capacity. The Standard model offers 4.4 kW of power and 11.4 kWh of usable capacity.
Importantly, the EverVolt system is modular, meaning that you can add multiple battery products to your storage setup if you want even more backup power. Panasonic’s EverVolt spec sheet indicates that you can connect up to two of their 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.
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.
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 are designed to provide both of these services.
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 Panasonic EverVolt has a roundtrip efficiency of 84% for AC-coupled batteries and 89% for DC-coupled batteries; this means that for every 10 kilowatt-hours (kWh) of electricity you put into the battery, you’ll receive 8.4 kWh of output from AC products and 8.9 kWh of output from DC products. You can read more about the difference between AC and DC batteries in our article specific to different battery technologies.
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. Unfortunately, the Panasonic EverVolt doesn’t list a depth of discharge on its spec sheet.
Panasonic EverVolt warranty coverage
- Warranty period: 10 years
- Guaranteed end-of-warranty capacity: 60%
- Throughput warranty: 7.56 MWh per module
The EverVolt battery line is backed by 10-year product and performance warranties that cover the product in the case of faulty parts or defects, as well as the actual performance of the battery. Panasonic’s 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 30.24 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 45.36 MWh, whichever happens first.
Importantly, Panasonic’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.
Warranty, capacity, and power are three of the most important metrics you should consider when comparing home battery options. If you’re curious to learn more about the best way to perform your own battery comparisons, check out our video explaining how to evaluate your home energy storage options:
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 Panasonic EverVolt 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. Panasonic has said to expect EverVolt prices between $15,000 and $20,000 (including installation), with the low end of the scale being for Standard batteries, and the high end for the Plus model.
If you want to install the EverVolt as part of a solar-plus-storage system, battery costs are just one piece of the equation. 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 Panasonic EverVolt 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.
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 EverVolt, 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 EverVolt batteries together to increase your storage capabilities.
Where to buy the Panasonic EverVolt
The Panasonic EverVolt battery is currently available online through Panasonic’s website, where you can request a quote and through any solar and/or energy storage installation company that is a certified Panasonic 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 EverVolt 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.