Generac PWRcell expert review: is it the right battery for you?

The Generac PWRcell (pronounced “power cell”) is a whole-home solar battery backup system from a trusted American company long-known for its backup generators. 

The power output and energy storage capacity can be customized to meet the needs of many different kinds of homeowners. For an average-sized home, a new solar installation with a Generac PWRcell backup battery will cost around $40,000.  The actual cost to install a Generac PWRcell battery varies depending on your needs. 

We think the Generac PWRcell is a great home battery, but it didn’t quite make the list of the best solar batteries on the market. Primarily, we find the system to be too expensive and underpowered compared to other options.

If you can find a good price from a trusted installer, we recommend the PWRcell only for a new solar installation—people with existing solar panels should look elsewhere.

Overview of the Generac PWRcell

In the video below, SolarReviews’ founder Andy Sendy breaks down some of the key things to know about the Generac PWRcell:

Like other home solar batteries, the Generac PWRcell is designed to store energy generated by your solar panels and provide backup power in the event of a grid outage and save homeowners money by helping them avoid costly peak energy charges under Time of Use (TOU) energy rate plans.

A PWRcell home solar system consists of four main components:

• Solar panels (the system works with panels from many brands)

• SnapRS rapid shutdown devices that go between each solar panel for fire safety

• PV Link solar string optimizers that optimize the DC power output of multiple solar panels 

• A PWRcell battery cabinet, which stores solar energy for later use

• The Generac PWRcell hybrid solar inverter charges the batteries and converts DC solar power into AC power for use in your home

Inside the PWRcell’s battery cabinet are battery modules, each of which can hold 3 kilowatt-hours (kWh) of usable electricity. A minimum of three modules and a maximum of six modules can be used for a range of 9 to 18 kWh of storage. Two battery cabinets can be paired with a single inverter.

Generac PWRcell cost

The Generac PWRcell system costs between $14,000 and $25,000, depending on the size of the battery and your location. The total cost for a typical home solar system with 15 kWh of PWRcell battery backup would be around $40,000.

Because the Generac PWRcell system is customizable based on the needs of each specific customer, the prices we have available are ranges. In addition, these products are sold through a nationwide network of licensed dealers, so pricing can vary depending on the area where you live.

This table shows estimated pricing for the PWRcell in some common configurations:

PWRcell battery size	Solar installation size	Number of PWRcell inverters	Type of use	Cost
9 kWh (3 battery modules)	6 kW	1	Small emergency backup	$32,000
15 kWh (6 battery modules)	6 kW	1	Typical emergency backup	$40,000
36 kWh (12 battery modules)	12 kW	2	Whole home backup	$72,000

Those prices might seem high—and they are. The Enphase IQ 5P and the Tesla Powerwall cost less than the Generac battery system.

One bit of good news on cost is that the PWRcell is eligible for solar battery rebates and other incentives in some areas. You can also claim the federal clean energy tax credit based on the total cost of the system. These incentives (as well as other applicable incentives and rebates you may qualify for) can substantially reduce the cost of a solar-plus-battery storage system.

How the Generac PWRcell works

Unlike other home solar batteries, Generac PWRcell is not just a battery box that hangs on your wall. Instead, it is an integrated system of components that can work together to make the energy storage system more effective and efficient. Generac makes every piece of equipment for a home solar system, except for the solar panels, wires, and racking.

A PWRcell system includes the following main components:

• SnapRS inline disconnect switches that go between each solar panel and allow for rapid shutdown in case firefighters need to work on the roof.

• PV Link substring power optimizers that take energy from the panels and send it to the battery and inverter.

• PWRcell battery modules to store solar energy, inside a specially-designed battery cabinet.

• A PWRcell solar islanding inverter that connects everything together and sends power to the electrical panel in your home.

Here’s how they all fit together:

Now let’s look at each of the components that come with the PWRcell system.

SnapRS switches and PV Link optimizers

These are fairly straightforward pieces of hardware that have an important job in the PWRcell system.

The SnapRS switches connect between each solar module in an array and will shut down the output of that module within 10 seconds from whenever the inverter is turned off. Rapid shutdown is a fire code requirement of solar systems, and these switches are how Generac accomplishes this task.

The PV Link boxes are substring power optimizers. They attach between a short string of solar panels (up to 2500 W) and the inverter, and ensure that the DC power delivered by the panels gets sent to the inverter as soon as panel output reaches 60 volts. The PV Link was initially developed by Pika Energy to integrate with the PWRcell battery.

Because they optimize the power output of a string of panels, the PV Links are somewhat less efficient than microinverters and DC power optimizers, which are attached under each solar panel in an array. The advantage of the PV Link is having fewer points of failure, at the expense of a little less energy output over time. For people who want the extra juice, Generac has announced its own microinverters, but they are not yet available for purchase.

The PWRcell battery cabinet

The PWRcell battery cabinet can hold up to 6 modules, each of which can store 3 kWh of usable electricity. The cabinet can be set up with 3, 4, 5, or 6 modules, allowing 9 - 18 kWh of storage. Here’s how that looks:

If installed alongside the PV Link optimizers and SnapRS rapid shutdown devices, the PWRcell’s battery is charged using DC power sent directly from the solar panels. This makes the battery very efficient compared to batteries like the Tesla Powerwall and sonnenCore, which charge using energy that gets converted from DC to AC and back again, causing some loss of energy in the process.

Learn more: Is a DC or AC battery right for your home?

The PWRcell inverter

The Generac PWRcell inverter was designed to operate a home in grid-connected or “islanding” mode in case the grid is down. It can be set by the homeowner to one of several modes, including backup power, self-supply, time-of-use, and zero-export.

The inverter comes in two models:

• X7602, which can provide up to 7,600 W of single-phase AC power when connected to the grid

• X11402, which can provide up to 11,400 W of 3-phase AC power when connected to the grid

Most homeowners will end up with the X7602, while commercial businesses are the target customer for the X11402.

Both inverters can accept up to 30 A @ 420 VDC from solar panels, and both output 9,000 W continuously in islanding mode when connected to one 18-kWh PWRcell battery cabinet. Both inverters can deliver up to 12,000 W to start a motor. That’s a very impressive number, as it means a PWRcell inverter can start a well pump, sump pump, or a 3-ton HVAC unit.

Optional components in the PWRcell system

In addition to the required components, Generac also makes some optional pieces of equipment to provide extra flexibility. They are:

• Automatic transfer switch (ATS)

• Smart Management Modules (SMMs)

• Sure-Start HVAC soft start box

This is where the PWRcell system really eclipses other home energy storage solutions. Generac brought these components from their home generator business to complement the PWRcell battery. The ATS and SMMs automatically shut certain appliances down, based on priority, to start up other appliances that require high surge power.

Using these components, homeowners can run nearly their entire home on a single backup battery in the event of a grid outage—something many other companies’ batteries can’t provide. Altogether, this makes the Generac PWRcell one of the most exciting home batteries on the market.

Automated Transfer Switches

These specialized pieces of equipment control the flow of power inside the home. As the name implies, they automatically send power to appliances, the PWRcell battery, or the grid, depending on the needs of the home at any given time. In addition, the Generac ATS isolates the solar and battery during a power outage, allowing them to continue to operate independently from the grid in “islanding mode.” Finally, using a Generac ATS can allow a single PWRcell inverter to manage up to four individual HVAC units, turning them on and off so they don’t overload the inverter’s capacity by starting all at once.

PWRmanger

Generac’s most recent innovation is the PWRmanager, which it calls an “advanced load management device.” This small box can take the place of several SMMs, providing a centralized automatic load management solution. Essentially, the PWRmanager’s job is to selectively shut off certain loads to prevent too much current from being drawn at once. This allows the PWRcell to provide whole home backup while not overloading the inverter. Users can also turn individual circuits on and off by using Generac's PWRview app.

Sure-Start HVAC soft start box

This piece of equipment is used to reduce the start-up current that an air conditioner compressor needs. It further reduces the peak power consumption needed and allows the PWRcell system to keep running essential equipment as an air conditioner starts.

How Generac’s optional components work

Here’s a look at how SMMs and a Sure-Start box work within the PWRcell system:

The image above shows how the PWRcell can power three of the most important appliances in the home as it operates in a grid-down situation. Here’s what’s happening, from bottom to top right in the image:

• The sump pump is wired without an SMM so it will always receive power when it needs it

• The well pump is set to Priority 1 using an SMM to turn it on whenever it needs to run to supply water to the home

• The 3-ton A/C is set to Priority 2 and allowed to run when the well pump is not running. A Sure-Start box is attached to keep the current it draws from overwhelming the inverter

• The 5-ton A/C is set to “lockout” using an SMM, which means it will not turn on when the grid is down, because it would draw more power than the PWRcell inverter can provide

Generac’s PWRview monitoring app

Another optional addition to your PWRcell system is Generac’s PWRview monitoring app.

It’s a one-stop-shop for information about energy generation and usage in your house. The app contains data on solar generation, battery charge, grid usage, and more - and can even give you an estimate of your next utility bill based on that data it’s collected if you enter your rate plan.

It certainly sounds like a good app to have, and its functionality is similar to other solar monitoring solutions from equipment manufacturers and solar installers. Unfortunately, reviews of Generac’s Android and iOS apps are not positive. Users complain about glitches, missing data, bad customer service, and more. This seems to be one area where Generac has stumbled, in regards to its PWRcell system.

If you’re curious about how the app works, check out the below video about its features.

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:

Component	Warranty coverage
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
SnapRS	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 or 3 days with little to no sun, something you very well may experience - especially in the wintertime. An alternative to an oversized solar system is a fossil fuel backup generator.

The PWRcell system can interface with two kinds of Generac backup generators: the Guardian HSB and the new PWRgenerator. Guardian series generators start at 10 kW of power output and top out at 26 kW, while the PWRgenerator puts out 9 kW. Generac says the Guardian series is better for those who want whole home backup with minimal load management and the ability to start large loads of 50 amps or greater, while the PWRgenerator is better for those who want the quietest possible generator that uses as little fuel as possible.

These generators are the backup to your backup. The PWRcell system will detect whenever the battery discharges to 30%, then turn on the PWRgenerator to recharge the battery to full. Generac says the PWRgenerator can charge a 12-kW battery from 30% to full in about an hour, and the Guardian series generators would do it even quicker. Depending on the size and model of the generator, these options can cost between about $5,500 and $9,500.

Although a generator and the PWRcell system should keep your home running during extended power outages as long as you have fuel and sun, Generac has shied away from saying the system can work in a true off-grid setting. That kind of promise has to come with robust provisions for redundancy and the proven ability to perform a black start (aka, start up the whole system with no outside power source), and Generac hasn’t done the testing and extra work to prove that.

More information on how the PWRgenerator works is available in this Generac datasheet (PDF), and information on Guardian series models is here.

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 available in multiple capacity sizes of between 9 kWh and 18 kWh; two can be connected together for a total of 36 kWh of storage.

• Tesla Powerwall 3 is a single DC-coupled battery box that comes in one size: 13.5 kWh. Multiple Powerwall batteries can be installed together.

• LG Chem RESU Prime batteries are DC-coupled batteries that come in 9.6 and 16 kWh sizes. They must be paired with an inverter that is built for paired storage, and most of these inverters can accept up to two RESU batteries.

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
Power connection	DC	AC	DC
Battery chemistry	Li-NMC	Li-NMC	Li-NMC
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
Round-trip efficiency	96.50%	90%	>90%
Warranty	10 years	10 years	10 years
Throughput warranty (MWh per kWh of storage)	2.52	2.8	3.35
End-of-warranty capacity	N/A	70%	70%
Average installed cost	$12,000 - $19,000	$11,500	$9,000 - $12,000
Energy monitoring app	Yes	Yes	3rd party
EV charging in-app	No	Yes	No
Load prioritization	Yes	No	No
Generator integration	Yes	No	Depends on inverter

*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.

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.

Concerns about past performance

There have been many reports of performance issues from users of Generac’s original version of the PWRcell system. In particular, the original versions of the SnapRS rapid shutdown devices (801 and 801A) seem to have had a flaw that could cause them to overheat and undergo thermal failure, leading to a lawsuit from at least one company, Power Home Solar. Generac has since developed a new version of the rapid shutdown device, the SnapRS802, to replace the older versions.

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, but don’t expect Generac to support that method of installation. Again, despite designing for integration with its generators to extend the backup capabilities of the PWRcell, Generac does not officially endorse the use of PWRcell in off-grid solar setups.

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’re 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 one of the best batteries 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.