Tesla Powerwall 2 vs. Generac Pwrcell: Which Battery Wins the Power Struggle?

Both are solid options. The best battery will depend on your energy needs.

A solar battery can save you from power outages and high electricity rates. But which is the best one for your home? 

That depends on your home's energy needs and what you want to accomplish. 

The Tesla Powerwall 2 and Generac Pwrcell are two of the most popular solar batteries on the market. Both are very different batteries, but both are pretty good. The Tesla Powerwall 2 did rank higher than the Generac Pwrcell on CNET's review of the best solar batteries, but only just barely. The Powerwall and Pwrcell each offset their weakness in one category with a win in another, making this battery battle difficult to call. 

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Here's how the Tesla Powerwall 2 and Generac Pwrcell stack up against each other.

Courtesy of Tesla, Inc.

What we like:

  • Unlimited cycle warranty
  • Well-rounded performance and efficiency 
  • Compatible with and without solar panels

What we don't like:

  • Not very modular
  • Glitchy energy management app
  • Bad customer service reputation

What we like:

  • Extremely modular design
  • Easy capacity upgrades
  • Good performance and efficiency

What we don't like: 

  • Can't install a third-party inverter
  • Bad customer product and support reviews

Tesla Powerwall 2 vs. Generac Pwrcell

Category Tesla Powerwall 2Generac Pwrcell
Usable capacity 13.5 kWh9 kWh - 18 kWh (Installed in increments of 3 kWh)
How many can I stack? Up to 10 Powerwalls (135 kWh)Up to two battery cabinets (36 kWh)
Round-trip efficiency 90%96.50%
Depth of discharge 100%84%
Peak power output (on-grid) 7 kW4.5 kW - 9 kW
Continuous power output (on-grid) 5 kW3.4 kW - 7.6 kW
Battery type Lithium-ionLithium-ion
AC- or DC-coupled system? AC-coupledDC-coupled
Price $9,000 to $14,000$10,000 to $20,000

Warranty winner: Tesla Powerwall 2

The Tesla Powerwall's warranty takes the win. Both batteries have nearly identical warranties in terms of years covered and end-of-warranty capacity guarantee. But it's the Powerwall's unlimited cycle warranty that makes it superior. Instead of going by cycle count, each individual Pwrcell battery module comes with a throughput clause. 

A battery's throughput is essentially the manufacturer's estimate on the total amount of energy it expects the battery to deliver during its lifetime. Regarding the Pwrcell, Generac expects each battery module to deliver 7.56 MWh of energy during its lifespan. But once a battery module hits its throughput of 7.56 MWh, warranty coverage for that battery module will end, even if you haven't hit the 10-year warranty mark. 

The Tesla Powerwall's warranty does not include a cycle or throughput clause, meaning you can cycle (drain and recharge) the battery as much as you want without having to worry about your warranty ending. 

Warranty details

Category Tesla Powerwall 2Generac Pwrcell
Years covered 10 years10 years per battery module
Cycles/throughput clause Unlimited cycles7.56 MWh per battery module
End-of-warranty capacity guarantee 70%70% per battery module

Capacity and modularity winner: Generac Pwrcell

One of the Pwrcell's main selling points is its modularity. Instead of one giant battery box, the Pwrcell is designed as a battery cabinet containing individual battery modules. One battery module stores 3 kWh. And each battery cabinet can hold 9 kWh to 18 kWh, with capacity increments of 3 kWh. This allows homeowners easier access to the capacity that fits their home's energy needs "just right." Upgrades are as simple as an installer inserting a new 3 kWh battery module into the battery cabinet. You won't have to buy a giant battery every time you need a capacity upgrade. Once you hit maximum capacity in one cabinet (18 kWh), an additional battery cabinet can be installed, raising your max capacity to 36 kWh.

One Tesla Powerwall holds 13.5 kWh of energy. And yes, this is a larger starting capacity than the Pwrcell. But if you find yourself needing more than 13.5 kWh, you'll have to buy another Powerwall, costing you more money in the long run. Tesla Powerwall batteries are only available in one size, so if you're looking for less than 13.5 kWh, the Pwrcell would be the better option in that situation. 

It's worth calling out that Tesla Powerwall batteries have a significantly larger cap-off for capacity. You can install up to 10 Powerwalls for a maximum capacity of 135 kWh. However, most homeowners won't need anywhere close to that much. 

Performance and efficiency winner: Generac Pwrcell

In terms of performance and efficiency, the Generac Pwrcell comes out on top. The Pwrcell has a higher round-trip efficiency and power output ratings (at larger capacities) than the Tesla Powerwall 2. But that's not to say the Powerwall is bad. It actually has some of the most well-rounded performance specs of other batteries we've reviewed. The Powerwall also has a much higher depth of discharge than the Pwrcell, meaning you'll be able to safely use more of your battery.

Performance and efficiency details

Category Tesla Powerwall 2Generac Pwrcell
Round-trip efficiency 90%96.50%
Depth of discharge 100%84%
Peak power output 7 kW4.5 kW - 9 kW
Continuous power output 5 kW3.4 kW - 7.6 kW

Price: Tesla Powerwall 2

The cost of a Tesla Powerwall 2 is estimated to be anywhere from $9,000 to $14,000. In the solar battery world, this seems pretty fair for a 13.5 kWh battery. The price range for a Generac Pwrcell is much broader because there are multiple capacity options. 

The Generac Pwrcell is estimated to be between $10,000 to $20,000. This price range is representative of the price of the Pwrcell at minimum capacity (about $10,000 for 9 kWh) and maximum capacity (about $20,000 for 18 kWh). The Powerwall wins the pricing category because you'll likely be spending less per kWh with a Tesla Powerwall 2 than you would with the Generac Pwrcell. 

But keep in mind that these price ranges don't factor in additional costs, such as installation labor and shipping. These are also price estimates. To get the most accurate price for your home, you'll need to get a proper quote from an installer. Gather multiple quotes to see which installer will go the lowest.

Which battery is better?

Both batteries are solid options for your home. The "best" battery of the two depends on your home's energy needs and your individual energy goals.

If you're looking for a battery with well-rounded performance specs, large capacity and a decent price for its size, the Tesla Powerwall 2 is a good choice. It's also a decent option for those without solar panels who are just looking for a home battery backup.

But if you're more interested in a modular battery with more size variables, easy capacity upgrades and solid performance and efficiency, then the Generac Pwrcell might be a better option for your home. 

But don't limit your battery search to just the Powerwall and Pwrcell. Look for solar panel installers in your area and see which batteries they carry. To get the best price possible, we recommend gathering as many quotes as you can before making a decision. A mix of quotes from national and local installers will give you the best price variety. 

Check out CNET's individual reviews of the Tesla Powerwall and Generac Pwrcell for finer details.

Read more: Want something smaller than a whole-home solar system? See our picks for the best portable solar panels and solar generators.

Frequently asked questions

What is the Tesla Powerwall 3?

The Tesla Powerwall 3 is the next generation of the Powerwall battery. Tesla has shared little information about the battery and there's no spec sheet available yet. But we do know it's twice as powerful as the Powerwall 2, and it won't be compatible with other Powerwall models. 

The Tesla Powerwall 3 will be available to customers in 2024. Pricing and ordering details are still unknown.

How much does a Tesla Powerwall cost?

Prices for the Tesla Powerwall 2 typically range from $9,000 to $14,000 before shipping and installation. We strongly recommend getting multiple quotes from different Tesla-certified installers in your area to get the best price possible.

What is the capacity of the Generac Pwrcell?

One Generac Pwrcell unit can hold 9 kWh to 18 kWh, installed in increments of 3 kWh. An additional unit can be installed for up to 36 kWh of storage capacity.

Updated Oct. 6, 2023 11:07 a.m. PT

Written by  Sarah Drolet
CNET staff -- not advertisers, partners or business interests -- determine how we review the products and services we cover. If you buy through our links, we may get paid. Reviews ethics statement
Sarah Drolet Associate Writer
Sarah Drolet is an associate writer at CNET covering home energy, residential solar power and emerging energy technology. She previously wrote about home and moving-related topics for MYMOVE. Sarah graduated from Coastal Carolina University with a bachelor's degree in communications.
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