Having long been a leader in the backup power space, Generac is now moving into clean energy and energy storage, with the PWRcell line of batteries at the forefront of their new product fleet. 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. The Generac PWRcell starts at a base price of $9,900 before installation.
The PWRcell comes in four sizes, ranging from 9 to 18 kWh of capacity and 4.5 to 9 kW of power. You may need a few PWRcell batteries to truly go “off the grid”. A qualified EnergySage-approved installer can give you the best information about the Generac home battery system and other energy storage options available to homeowners today.
Generac PWRcell warranty coverage
- There’s a lot to talk about when it comes to the PWRcell battery system – skip down to any section here:. The Generac PWRcell 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.
- Installing a storage solution like the Generac PWRcell with a solar energy system allows you to maintain a sustained power supply during day or 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 Generac PWRcell 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.
- Pika’s original battery solution was designed with two major markets in mind. The first was locations with time-of-use (TOU) electricity rates, such as California, where electricity costs more during the hours of the day when demand is highest, which are often when the sun isn’t shining at its brightest.
Generac PWRcell warranties
Key things to know about the Generac PWRcell
The second was “zero export” markets, such as Hawaii, where solar system owners are prohibited from exporting their excess solar electricity to the grid. The battery has built-in operating modes that are designed to optimize household energy usage under each of these scenarios.
The Generac PWRcell starts at a price of $9,999 and scales up in cost for larger battery models. This price includes the battery itself, but not additional costs like installation and labor.
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. If you want to install the PWRcell 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 Generac PWRcell 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.
Generac describes the PWRcell, which first launched in September 2019 following the acquisition of Pika Energy, as a “truly scalable storage system with unmatched raw power.” As described in greater depth below, the technical specifications of the battery support these claims: the stackable PWRcell has among the most power of any residential battery currently on the market.
Alongside the PWRcell, Generac offers their own energy monitoring system, known as PWRview.
Complete with a custom mobile app, PWRview displays detailed electricity bill tracking and forecasting, as well as other useful energy dashboards.
You can also set daily and monthly goals on electricity usage within the application.
When evaluating the PWRcell, 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 Generac PWRcell comes in four different models, based on the number of battery modules: the PWRcell M3, PWRcell M4, PWRcell M5, and PWRcell M6. Two important metrics to keep in mind when comparing the PWRcell 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 PWRcell M6, the largest battery in the lineup, boasts a maximum power rating of 9 kW to go along with 18 kWh of usable capacity. The M3, M4, and M5 models boast 4.5 kW, 6 kW, and 7.5 kW of maximum power respectively. Importantly, the PWRcell system is modular, meaning that you can add multiple battery products to your storage setup. For example, you might want to install multiple PWRcell batteries for a home with high energy demands.
Can you go off-grid with the Generac PWRcell?
Generac’s PWRcell spec sheet indicates that you can connect up to two PWRcells to a single PWRcell inverter, so you’ll need to upgrade your supporting hardware to add even more 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 available energy capacity 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.
Frequently asked questions about Generac’s battery
The suite of PWRcell hardware and software products are designed to provide both of these services. Generac offers a solar inverter alongside their PWRcell. This inverter acts as both a battery inverter and a rooftop solar array inverter.
This means that, as long as your installer installs the correct components and the PWRcell inverter, your Generac PWRcell battery will be able to provide backup power for your home when the grid goes down, as well as interact with your solar panel system if you have one.
- Their monitoring technology is fully built-in to their PWRcell inverter, but Generac also offers their monitoring capabilities with the installation of a device known as PWRview.
- With the built-in inverter monitoring technology, Generac’s PWRcell batteries and their associated parts can intelligently manage electrical loads throughout your house and appropriately pull energy from the battery when needed.
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–or cycle–your battery, many battery manufacturers specify a maximum DoD level for optimal battery performance.
Where to buy the Generac PWRcell
In general, batteries with a higher depth of discharge are considered better quality products. The Generac PWRcell boasts a depth of discharge of 84 percent.
- 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 Generac PWRcell has a high roundtrip efficiency of 96.5 percent; this means that for every 10 kilowatt-hours (kWh) of electricity you put into the battery, you’ll receive 9.65 kWh of output.
Warranty period: 10 years . Throughput warranty: between 22.6 and 45.3 megawatt-hours (MWh), depending on battery size. In most cases, homes with a Generac battery will charge and discharge their battery every day. The PWRcell comes with a 10-year limited warranty.
For the different models of the PWRcell, Generac also notes a “throughput warranty”. A throughput warranty is another way to measure when the warranty period on a battery has been reached based not on time but rather on how much energy has been stored and discharged over its lifetime.
Overall, a PWRcell warranty is valid for either 10 years or the amount of time it takes to cycle the specified amount of energy through the battery, whichever comes first. (This is similar to car warranties – ten years or 100,000 miles, where the throughput of a battery is similar to mileage warranties.) The throughput warranty values for each PWRcell model are below:.
Importantly, Generac’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. 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. 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.
More reading on EnergySage
Going “off the grid” with solar batteries is actually a more expensive and complicated proposition than you might think. Most home batteries, including the PWRcell, only have enough capacity to store a few hours of electricity.
How Generac’s optional components work
If you want to make sure you can maintain power to your property for days at a time, you’ll need to install several PWRcell batteries together to increase your storage capabilities.
There are many, many questions you can (and should) ask about any battery you’re installing.
Here are a few more quick hits about the Generac PWRcell:. The Generac PWRcell battery is currently available online through Generac’s website where you can request a quote and through any solar and/or energy storage installation company that is a certified Generac/Pika 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 Generac 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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How much does the Generac PWRcell cost?
Top brands and…. How do solar batteries compare? Tesla Powerwall vs.
Tesla Powerwall alternatives: Generac PWRcell, LG Chem RESU,…. Add unbeatable flexibility and value to the PWRcell System by enabling whole home backup, controlled via the user-friendly PWRview app. The PWRmanager enables batteries to work smarter, so fewer batteries can power the home for longer.
This easy-to-install load management device integrates seamlessly with PWRcell, dramatically improving system performance. The microinverter technology that you’re familiar with, now from the leader in home energy technology. PWRmicros make high performance residential solar faster, easier, and more affordable. Generac PWRmicros simplify installation and maximize production, despite shade and complex rooflines.
Leading power throughput enables larger modules to produce at 100% without clipping, maximizing lifetime system value.
How does the Generac PWRcell work?
A permanently installed Generac home backup generator protects your home automatically. It runs on natural gas or liquid propane (LP) fuel, and sits outside just like a central air conditioning unit.
A home backup generator delivers power directly to your home’s electrical system, backing up your entire home or just the most essential items.
Each battery module can be purchased separately for $1,900 - $2,000, so the cost of a full-sized 18 kWh PWRcell system ranges from about $16,000 to $18,000 installed, depending on offers from dealers in your area.
The good news is that the PWRcell is eligible for solar storage incentives in certain areas. Not only that, when you install a solar system, you can claim the 26% federal solar tax credit. These incentives (as well as other applicable incentives and rebates you may qualify for) can reduce the cost of a solar-plus-battery storage system substantially.
Find out which incentives and rebates you qualify for when you install solar
PWRcell warranty information
Generac is a solid, reputable company that stands by its products. You can count on it to be around for decades to come. While that’s a good basis for trusting a warranty, the numbers need to be right. Let’s see how well they fare when it comes to offering their customers protection against product failures.
The good news is, the Generac PWRcell warranty covers parts, labor, and limited travel (100 miles/3 hrs maximum, per occurrence) for all components of the PWRcell system. The length of coverage depends on the product type and Generac promises the products will be free from defects in material and workmanship during their coverage period.
Here’s a look at how long each component is covered:
|PWRcell battery cabinet||10 years|
|PWRcell battery modules||10 years or 7.56 MWh of energy throughput per module; whichever comes first|
|PWRcell inverter||10 years|
|PV link||25 years|
Importantly, the pieces that are going to stay up on your roof for 25 years (PV Link and SnapRS) are warrantied for 25 years. The PWRcell inverter and battery come with 10-year warranties, which is fairly standard in the industry for these components.
Additionally, the throughput warranty for the battery modules is fairly standard. To put it in perspective, if you drained each battery module 100% of its usable power (3 kWh) every day, you’d get to 7.56 MWh in about 6.9 years. The vast majority of people will choose to retain some battery capacity for emergencies, and therefore, will use less. To get to the full 10 years, don’t go over an average of 69% drain per day.
Unfortunately, the PWRcell battery module warranty doesn’t say anything about how much capacity the modules will retain over those 10 years; only that they will be free of defects in materials and workmanship. If you think the batteries have lost more capacity than they should, it’s up to you to convince Generac of that, and up to them to agree with you.
This isn’t normal. Many other batteries on the market, including the Tesla Powerwall and its main competitors, guarantee between 60% and 70% of the original capacity at the end of their warranty periods. This is an oversight for Generac. We’ll update this article if that changes.
Can you go off-grid with Generac PWRcell?
Going off-grid with solar is not for the faint of heart. In general, you need to oversize your solar system and battery capacity to generate and store enough electricity to get through 2-3 days with little to no sun, something you very well may experience - especially in the wintertime.
Despite that, when it comes down to it, the Generac PWRcell is better-suited for an off-grid lifestyle than most other solar batteries. The modular battery can be hooked up with as little as 9 kWh of storage capacity or as much as 36 kWh in two cabinets. Using Generac’s SMMs and ATS as described above can allow you to run a good deal of home appliances off of one or two PWRcell inverters.
That said, unless you spend a lot of money to oversize your solar system, you’re going to need some form of backup generator. Many off-gridders turn to a fossil fuel generator on winter days when their solar systems aren’t producing enough and their batteries are low on energy.
The PWRcell system does not currently interface with Generac’s line of backup generators, but the company recently announced a new product they’re calling PWRgenerator. It’s a 9 kW backup generator designed to interface with the PWRcell system that runs on either natural gas or liquid propane.
The Generac PWRgenerator, coming in late 2022.
When the PWRgenerator becomes available, it will work by acting as a backup to your backup.
The system will detect whenever the PWRcell battery discharges to 30%, then turn on PWRgenerator to recharge the battery to full. Generac says the generator can charge the 12-kW battery from 30% to full in about an hour.
The generator is scheduled to be available sometime in early 2022, but there is no word on the price yet. Generac’s existing 9 kW home generators start around $2,800 plus installation costs. We’re guessing the PWRgenerator will add about $4,000-$5,000 to a PWRcell system, all-in.
Here’s the good news for existing PWRcell owners, and those who buy PWRcell without the generator: Generac has told SolarReviews that as long as a homeowner has an unused DC breaker in their PWRcell inverter, they can add a PWRgenerator.
More information on how it works is available in this Generac datasheet (PDF).
How PWRcell compares to other top home batteries
We’ve made allusions above to how PWRcell compares to Tesla’s Powerwall, but let’s make the facts more explicit here, and add a comparison to LG Chem RESU Prime batteries, which are another of the top home energy storage solutions.
PWRcell differs from the Powerwall and RESU batteries in a couple of key areas:
- PWRcell is a DC-coupled, modular battery system that comes with a lot of other solar equipment, must be installed at the same time as a new home solar system, and can be purchased in multiple capacity sizes
- Tesla Powerwall is a single AC-coupled battery box that can be added to an existing solar system, and comes in one size (though multiple Powerwalls can be installed together)
- LG Chem RESU Prime batteries are DC-coupled batteries that come in 9.6 and 16 kWh sizes and can be added to an existing solar installation
Here’s a comparison of key data points of these three market-leading home energy storage solutions:
|Generac PWRcell||Tesla Powerwall+||LG Chem RESU Prime|
|Capacity||9 - 18 kWh||13.5 kWh||9.6 - 16 kWh|
|Max. continuous output||4.5 - 9 kW||5.8 - 9.6 kW*||5 - 7 kW|
|Peak power output||6 - 12 kW||10 - 22 kW*||7 - 11 kW|
|Warranty||10 years||10 years||10 years|
|Throughput warranty (MWh per kWh of storage)||2.52||2.8||3.35|
|Average installed cost||$11,500 - $17,000||$10,500||$9,000 - $12,000|
|Energy monitoring app||Yes||Yes||3rd party|
|EV charging in-app||No||Yes||No|
*Tesla Powerwall+ output depends on whether the grid is up or down, and also increases when paired with a solar installation of at least 4 kW under full sun. A solar installation of more than 12 kW is necessary for peak power output of 22 kW.
One thing we can’t capture with a single data point is availability.
As of January 2022, both the Generac PWRcell and LG RESU Prime batteries are available from installers all around the country, while the Tesla Powerwall has at least a 3-6 month waiting period after ordering. All of the batteries listed above can be installed by many different solar installers, so contact companies near you to get quotes for solar and home energy storage.
The future of Generac’s PWRcell
Generac has announced several new products that will become available in 2022.
First up is the aforementioned PWRgenerator, which will allow PWRcell owners to have extra peace of mind in grid-down or off-grid situations. The generator will run on natural gas or LP and charge the PWRcell batteries if they get too low.
Next are PWRmicromicroinverters that can be used in a PWRcell system in place of the SnapRS and PV Link equipment. These pieces of equipment make it possible to optimize the output of one or two solar panels at a time, squeezing just a little extra efficiency out of the system and providing more accurate monitoring.
Finally is a new piece of smart technology called the PWRmanager. This box goes next to your home’s main electrical panel and intelligently controls all the circuits in your home to ensure the PWRcell system is never overloaded. It’s like an advanced version of the SMMs discussed above, and can be included in the PWRcell system as an option.
Bottom line: Is the Generac PWRcell system right for you?
As we outlined above, the Generac PWRcell is an exciting entry into the home energy storage market, and has some unique features that set it apart from the competition. If you’re looking for home battery backup for emergencies that can also help you avoid high peak energy costs under a Time of Use billing plan, the PWRcell is an excellent choice.
If you’re looking for a solution that can take you off the grid, the PWRcell may be just right for that too - especially after Generac releases the PWRgenerator “backup to the backup” in 2022. It won’t be as hearty as some true off-grid solar setups on the market, but it should be a heck of a lot more user-friendly.
The tradeoffs here are a somewhat higher price than the batteries from Tesla and LG, and the missing end-of-warranty capacity guarantee. Still, if you haven’t yet installed solar and are looking for a robust home battery system and you need to run critical appliances like a well pump, sump pump, and A/C during an outage, the PWRcell is probably the best battery on the market.
Find out if going solar and installing a solar battery like the Generac PWRcell is right for your specific home by using our solar panel cost and savings calculator below.
Find out how much a solar system would cost for your specific home
Ben is a writer, researcher, and data analysis expert who has worked for clients in the sustainability, public administration, and clean energy sectors.