If you are in the market for a solar panel system, you might be exploring whether or not adding batteries is the right choice for your home. Solar battery backup systems have the ability to solve two problems – providing power during outages and providing power during peak grid hours for customers in certain markets.
When referred to as “battery back up”, the stored solar power in the batteries provides power to the home during a grid outage. “Battery storage” can be used interchangeably with battery backup, but is more often used to describe using the power stored in the batteries to power the home during peak hours in order to reduce the home’s electricity costs from the grid.
In Public Service Solar’s markets in NJ, PA, and FL, the battery applications are all battery backup solutions – ensuring that customers are safe and powered during extreme weather events. As a Panasonic Elite Installer, Public Service Solar has decided to partner with Panasonic and offer EVERVOLT® battery products which when combined with Panasonic EVERVOLT solar modules complete a Panasonic Total Home Energy System.
A Panasonic EVERVOLT battery system is an intelligent energy management and storage system which contains several components which work together seamlessly for efficiency and reliability. Underneath the sleek facade of the battery cabinet is industry leading battery technology consisting of a battery, a hybrid inverter or AC inverter, and a battery management system (BMS).
In this article, we’ll do a deep dive into the specific components, their functions, and their benefits so you can feel educated and confident about battery technology and how your home can benefit.
EVERVOLT Solar Modules
When an EVERVOLT battery system is combined with EVERVOLT solar modules it completes the Panasonic Total Home Energy System. Although a solar powered source is not required to power the battery, without solar energy there is no way to replenish the battery in an outage. High performing solar modules are essential in keeping the battery modules charged especially during extended outages.
The Panasonic 420HK2 solar module is a high efficiency, high performance solar module warrantied for 25-years through Panasonic’s AllGuard warranty which also covers the racking and inverter. Its high efficiency of 21.7%, and power density of 20.2 W/ft², means more power with less space. Another key standout of Panasonic modules is its long term performance. A Panasonic EVERVOLT solar module is warrantied to be at 92% of its day one efficiency at year 25. Ensuring long term reliability and a consistent power source for your home and batteries.
The Battery Cabinet
When you look at the outside of a Panasonic EVERVOLT battery system you are actually looking at more than just a battery. The unit you are looking at from the outside is known as the battery cabinet, while within that cabinet there are battery modules, an inverter, and a battery management system.
Panasonic Batteries
The Panasonic EVERVOLT battery cabinet comes in three standard sizes, a 9 kWh, 13.5, and 18 kWh (with 20 kWh of usable power) making it the largest single battery offering on the market and an excellent choice for whole home battery backup. These lithium ion batteries from Panasonic have been in demand for some time now. In fact, since 2009 Panasonic has actually been supplying lithium-ion cells for Tesla’s battery inventory at their Gigafactory in Nevada.
How does the Panasonic EVERVOLT compare to Enphase and Tesla? Enphase and Tesla both offer solid battery products for homeowners. Like any product, they have their own benefits and limitations.
| Feature | Panasonic EVERVOLT | Tesla Powerwall | Enphase IQ Battery |
| Usable Capacity | 20 kWh | 13.5 kWh | 5 kWh |
| Continuous Power Output | 7.6 kW | 11.5 kW | 3.84 kW |
| Peak Power Output | 9.6 kW | 11.5 kW | 7.68 kW (with 2 units) |
| Coupling Type | AC or DC coupled (Hybrid/AC systems) | AC-coupled only | AC-coupled (each unit includes its own microinverter) |
| Stackability /Expansion | Yes, 4 batteries up to 80 kWh | Yes, 4 batteries up to 54 kWh | Yes, 8 batteries up to 40 kWh with System Controller. |
| Warranty: | 12 years | 10 years | 15 years |
While Enphase’s battery warranty is strong, Panasonic wins on size for a single battery. Storage size or capacity is important especially in a backup situation. Solar panels can continue to charge the battery in an outage, but during nighttime or if there is snow on the panels you will need a large capacity battery to get you through the storm.
EVERVOLT Hybrid Inverter
The Panasonic Hybrid inverter rests at the top of the battery cabinet. It provides an important function of converting the DC power stored in the batteries into AC power used by the home. Solar battery backup systems using the hybrid inverter are extremely efficient as the DC power produced by the solar panels will charge the DC battery directly with no conversion or energy loss necessary. It also manages the charging and discharging of the battery converting between AC and DC as needed.
The hybrid inverter is a string inverter for the solar panels as well as an inverter for the battery. Despite the high efficiency of the Panasonic hybrid inverter, many homeowners and installers will prefer to use the AC coupled version on the inverter allowing them to install microinverters and for easy retrofits on existing systems.
EVERVOLT AC-Coupled Inverter
For a system that is converting the power from DC to AC through microinverters or an independent string inverter, an internal AC-coupled inverter is needed for the battery instead of the hybrid inverter.
In an AC-coupled system, solar panels produce DC but are connected to microinverters (like Enphase) or a string inverter, converting it to AC immediately. That AC powers your home but when sending power into the battery it must be converted back to DC via an internal inverter in the battery cabinet.
Battery Management System (BMS)
Between the battery modules and inverter is the Battery Management System (BMS) of the EVERVOLT battery cabinet. The BMS is critical to ensuring the batteries are functioning properly by constantly checking the voltage, temperature, and current coming from the individual modules and cells within the battery. It tracks the charge level (State of Charge – SOC) and health of the battery (State of Health – SOH). It protects the battery from overheating, overcharging or discharging, and short circuiting. The BMS is also what communicates with the inverter, automatic transfer switch (ATS), and SmartBox to ensure uninterrupted energy flow and system longevity.
EVERVOLT SmartBox
The Smartbox itself is small in size when compared to the rest of the EVERVOLT battery system, but don’t let its small size fool you, it handles key functions for the battery system, and without it, the batteries would be unusable in an outage event.
Load Management
When opening the cover of this box, its primary function is clear. This box determines which parts of your home get power in the event of a grid outage by housing selected backup loads. During the approval process, you will be contacted by our master electrician, who after reviewing your home’s critical loads and the battery technology, will discuss with you what household loads your batteries can support. We aim to prioritize essentials like refrigerators, Wi-Fi routers, lighting, medical equipment, and garage door openers.
Automatic Transfer Switch (ATS)
The ATS is integrated into the SmartBox and handles the seamless transition between grid power and battery backup during an outage. When the grid goes down, the ATS disconnects the house from the grid and powers selected loads (or the entire home, depending on your setup) from the battery.
System Monitoring
The SmartBox houses current transformers (CTs) that measure energy usage on your main panel and backup loads panel. It also contains communications hardware that talks to the battery, inverter, and the EVERVOLT app.
Conclusion
The Panasonic EVERVOLT battery system is a powerful, flexible solution for homeowners looking to take control of their energy use and stay protected during outages. With options for both AC- and DC-coupled setups, stackable storage capacity up to 80 kWh, and intelligent monitoring through the EVEROLT app, it’s designed to meet a wide range of home energy needs. Backed by Panasonic’s trusted name, a 12-year warranty, and a robust SmartBox that manages critical loads and power flows seamlessly, the EVERVOLT battery offers peace of mind in one sleek, reliable package.
Whether you’re installing a new solar system or adding storage to an existing one, the EVERVOLT is built to adapt, perform, and protect. Contact Public Service Solar today to learn if battery backup is right for your home.
