Solar panels are gaining popularity for many reasons, but they won’t help you in a blackout. You’ll need a home battery system for that. Just like solar panels, that battery will need to meet the particular needs of your home — they aren’t one size fits all.
The Generac Pwrcell was released in 2019 and has since become one of the most recognizable batteries in the solar industry. This solar battery was designed to make it easy for homeowners to get the exact battery capacity that they need for their home’s energy needs.
“The thinking behind the battery and surrounding energy storage was that not all homes are created equal,” Rex Liu, Generac’s vice president of product management, told CNET. “The needs of every homeowner could be very different, so having a modular battery was something that could bring a lot of value to the market overall. An installer can optimize the solution for their particular homeowner customer.”
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Solar batteries are big, bulky, expensive and part of a holistic home energy system. That makes them difficult to put through hands-on testing. This review is based on specs and information provided by Generac online and an interview with Liu to get the most accurate and up-to-date information.
Here’s what you should know about the Generac Pwrcell.
What do I get with the Generac Pwrcell?
The Generac Pwrcell is one of the most modular batteries we’ve seen. In our review of the best solar batteries, the Pwrcell stood out in its modularity, capacity sizes, efficiency and performance. Here’s a quick look at the Generac Pwrcell’s specs.
Generac Pwrcell specs
|9 kWh – 18 kWh (Installed in increments of 3 kWh)
|How many can I stack?
|Up to two battery cabinets (36 kWh)
|Depth of discharge
|Peak power output (on-grid)
|4.5 kW – 9 kW
|Continuous power output (on-grid)
|3.4 kW – 7.6 kW
|AC- or DC-coupled?
|$10,000 – $20,000
The Generac Pwrcell is more than just a battery box that sits in your garage or hangs on the wall. It’s an intricate, DC-coupled system with quite a few components. Here’s a quick breakdown of the Pwrcell system:
Battery cabinet: The Pwrcell stores energy a bit differently compared with other solar batteries. Instead of a battery box, the Pwrcell system has a battery cabinet, which houses several lithium-ion battery modules. The battery cabinet houses three to six battery modules. The number of battery modules in the cabinet reflects the storage capacity available. A second battery cabinet can be installed for additional capacity.
Inverter: The main function of the inverter is to convert DC energy from the solar panels and battery into AC energy to power your home. Since the Pwrcell is a DC-coupled system, you’ll have to use the Generac inverter that is provided with the Pwrcell.
Automatic transfer switch: The ATS provides an automatic transition to back up battery power in a power outage.
PV link: This helps optimize how power is generated by your solar panels and stored in the battery. It also works with a rapid shutdown device connected to the solar panels.
Capacity and modularity
The capacity and modularity categories are where the Pwrcell shines the brightest, scoring as the most modular battery on our rankings of the best solar batteries. The Pwrcell stores energy in individual battery modules contained within a battery cabinet. One battery cabinet holds between 9 kWh and 18 kWh of energy, with capacity expandable in increments of 3 kWh. This design allows homeowners easier access to the capacity size that is “just right” for their home’s energy needs.
Upgrading the Pwrcell’s capacity is easy. Instead of buying a whole new battery, you’ll just purchase a new battery module. You’ll have to hire an installer to insert the new battery module. Once you hit the maximum capacity (18 kWh), you’ll need to install an additional battery cabinet. You can have up to two battery cabinets, for a maximum capacity of 36 kWh.
|Number of modules installed
Performance and efficiency
The Pwrcell has a higher-than-average round-trip efficiency of 96.5%. This means only 3.5% of your electricity gets lost on its way to battery storage. Of the lithium-ion batteries we looked at, the average efficiency was about 90%. However, the Generac Pwrcell’s depth of discharge is one of the lowest we’ve seen for lithium-ion solar batteries, at 84%. A battery’s depth of discharge is a limitation set by the manufacturer on the percentage amount of energy that can be drained all at once without damaging the battery. The average depth of discharge for a lithium-ion solar battery is about 95%.
The Pwrcell also performs well in the power output category, with an on-grid peak power output range of 4.5 kW – 9 kW and an on-grid continuous power output range of 3.4 kW – 7.6 kW. A battery’s peak power output rating is the maximum amount of power it can output all at once, and is normally used when large appliances or power loads kick on. A battery’s continuous power output is the amount of power the battery can output all the time.
The exact amount of power output from the Pwrcell depends on the installed capacity. In other words, the higher the battery capacity, the higher the power output.
Performance and efficiency details
|Depth of discharge
|Continuous power output
|Peak power output
|4.5 kW – 9 kW
|3.4 kW – 7.6 kW
How’s the Pwrcell’s warranty? It’s pretty much the industry average, which isn’t a bad thing. Here’s what it includes:
- 10 years (includes battery cabinet, inverter and each individual battery module)
- 7.56 MWh throughput per battery module
- 70% end-of-warranty capacity guarantee
Ten-year warranties are pretty standard with solar batteries, but it’s nice to know the entire Pwrcell system is covered. However, each Pwrcell battery module does come with a throughput clause. This is essentially the manufacturer’s estimate on the total amount of energy it expects the battery to deliver during its lifetime. In this case, Generac expects each battery module to deliver 7.56 MWh of energy during its lifespan. Be aware that once a battery module hits its throughput (7.56 MWh), it is no longer covered under warranty.
The Pwrcell also comes with an end-of-warranty capacity guarantee of 70%. This is Generac’s guarantee that each battery module will be able to hold at least 70% of its maximum energy capacity by the time your warranty expires. It’s also worth noting that the PV links are warranted for 25 years, and the automatic transfer switch for five years.
|End-of-warranty capacity guarantee
|7.56 MWh per module
As a company, Generac doesn’t have the best product or customer service reviews. Many customers have left complaints on Generac’s Better Business Bureau page about products breaking after a couple years of use, with some customers even referring to Generac as “Junkerac.” These complaints are mainly focused on their Pwrcell systems and generators. Many customers have also had bad experiences with Generac’s customer support surrounding warranties, with Trust Pilot reviewers saying Generac was not honoring the warranty.
Generac PWRview app
The Generac Pwrcell is compatible with Generac’s well-rated energy management app – PWRview. The PWRview app monitors your solar production, shows your battery’s state of charge and tells you when you’re drawing power from the grid and when you’re feeding power to the grid. The app also keeps track of your historical energy data to help calculate estimated savings.
How much does the Generac Pwrcell cost?
The Generac Pwrcell is estimated to cost between $10,000 and $20,000 before installation. Cost is reflective of how many battery modules you have installed: The higher your battery capacity, the higher the price tag. Other factors affecting price are location, the installer and the amount of solar on your roof. As a rule of thumb regarding battery pricing, you can usually expect to pay between $1,000 and $2,000 per kWh of energy storage.
For the most accurate pricing, you’ll need to speak with a Generac Pwrcell-certified installer in your area. We recommend gathering a few quotes from national and local installers to see who will give you the best price possible.
Is the Generac Pwrcell my best choice?
It depends on what you’re looking for in a battery and what your energy storage goals are. In terms of its technical specs, the Pwrcell is a decent battery, excelling in modularity, capacity and efficiency. But don’t limit your options to just the Pwrcell. Explore multiple battery storage options on your own or with an installer. Most installers are certified to install multiple brands of batteries, so don’t feel like you only have one option.
How we evaluated the best solar batteries
Not every battery is the right fit for every home. Without an on-site inspection, it’s difficult to determine which solar battery is the “best” battery for home and energy needs. Due to the complexity of solar panel systems, we’re unable to do any hands-on testing of these solar batteries. However, there are ways to objectively evaluate and compare these batteries. Here’s how we evaluate solar batteries.
First, we created categories to evaluate the battery’s efficiency, performance, capacity and value. We also gave each category its own weight. A category’s weight reflects the importance we felt was relevant to the average consumer. Here are the categories we considered and their weights:
- Battery modularity (stackability) – 20%
- Warranty – 20%
- Round-trip efficiency – 15%
- Depth of discharge – 10%
- Power output – 10%
- Price – 10%
- Customer reviews – 10%
- Battery capacity – 5%
We looked at over 15 of the most common batteries on the market and collected the data for each category to compare the numbers. Each category (for every battery) was given a tier-style rating (from 1 to 5) to see which metrics of each battery were above average (among those on our list), average or below average.