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Tesla Powerwall Vs Generac PWRcell

Updated: Jun 17

Picking the right energy storage is not just for those blackout moments. A good system can help you manage your energy use better, save money on your bills, and make the most out of your solar setup. Plus, with solar and battery storage expected to make up 81% of new U.S. electric capacity in 2024, there’s no better time to get on board.

Now, if you’re looking into home energy storage, you’ve probably heard of the Tesla Powerwall and the Generac PWRcell. Both are top contenders, but each has its unique strengths that cater to different needs and preferences. Let’s dive in and see what Tesla Powerwall and Generac PWRcell bring to the table.

Key Takeaways 

  • Tesla Powerwall 3: High power output (11.5 kW continuous), 13.5 kWh capacity, 97.5% efficiency, seamless integration.

  • Generac PWRcell: Modular, scalable (9-36 kWh), 7.6 kW continuous power, 96.5% efficiency.

  • Value: Tesla is ideal for high-demand homes; Generac is perfect for flexible, scalable needs. Both benefit from tax credits and rebates.


Tesla Powerwall

Tesla Powerwall

The Tesla Powerwall is a popular home battery system designed to store energy from solar panels or the grid. It's a sleek, compact unit that can provide backup power during outages, help you manage your energy use, and even save on utility bills.

The Powerwall is a lithium-ion battery with a capacity of 13.5 kilowatt-hours (kWh) for both the Powerwall 2 and the new Powerwall 3. This means it can store a significant amount of energy, making it suitable for both emergency backup and daily use. During a grid outage, the Powerwall kicks in automatically, keeping your lights and essential appliances running without interruption. This can be a lifesaver during natural disasters or unexpected blackouts.

Key Features 

  • Integrated Inverter: The Powerwall 3 includes an onboard inverter, converting DC power from your solar panels directly into AC power for your home, reducing energy loss and improving efficiency.

  • High Power Output: The Powerwall 3 boasts an impressive continuous power output of 11.5 kW and a peak power output of 30 kW, which is enough to run high-demand appliances. 

  • Scalability: You can stack multiple Powerwalls to increase storage capacity, making it a flexible solution for homes with varying energy needs. 

  • Storm Watch: This feature automatically charges the Powerwall to full capacity when severe weather is forecasted, ensuring you have maximum backup power during storms.

  • Remote Control: Through the Tesla app, you can monitor and control your Powerwall from anywhere, optimizing your energy usage based on your needs.

Generac PWRcell

Generac PWRcell

The Generac PWRcell is a robust and flexible home battery system designed to store energy from your solar panels or the grid. It’s a top contender for those looking to enhance their energy independence and resilience.

The Generac PWRcell system is built with a modular design, meaning you can start with a basic setup and expand as your energy needs grow. Each battery module stores 3 kWh, and you can stack up to six modules in a single cabinet, providing up to 18 kWh of storage capacity. If you need more, multiple cabinets can be connected to a single inverter, allowing for up to 36 kWh of storage. This flexibility makes it suitable for various home sizes and energy needs.

The Generac PWRcell can keep essential appliances running during a grid outage, thanks to its high power output and advanced load management. It’s especially well-suited if you are looking for a reliable whole-home backup solution. Also, the modular design means you can start small and expand as needed, making it a cost-effective solution over time.

Key Features

  • Modular Storage: The PWRcell system’s modular design allows you to add more battery modules as your energy needs increase. This scalability ensures you only pay for what you need and can expand in the future. 

  • High Power Output: The PWRcell provides up to 7.6 kW of continuous power, which is sufficient to start large appliances like well pumps or HVAC units.

  • Advanced Load Management: With the PWRmanager device, the system intelligently manages your home’s energy load, prioritizing essential appliances during an outage to maximize battery life.

  • PWRview Monitoring App: This app gives you real-time insights into your energy usage, solar generation, and battery status, helping you make informed decisions to optimize your energy consumption.

Tesla Powerwall Vs. Generac  PWRcell 

Power Output  

The Tesla Powerwall 3 offers a continuous power output of 11.5kW and can peak at 30 kW. That's perfect for homes with high energy demands. In contrast, the Generac PWRcell provides up to 7.6kW of continuous power, which is still pretty solid, with peak outputs tailored for different configurations.

Round Trip Efficiency 

When it comes to efficiency, the Tesla Powerwall 3  stands out with a round-trip efficiency of 97.5%. This means it loses less energy during the charge and discharge process, which is a big deal. The Generac PWRcell, while still efficient as a DC-coupled system, has a slightly lower efficiency rate of around 96.5%.

Now, you might think, “What’s the big deal with a 1% difference?” Well, it can actually add up over time, especially if you’re using the system daily. For instance, with the Tesla Powerwall, only 2.5% of the energy is lost each time you store and use it. In contrast, the Generac PWRcell loses 3.5%. If you’re storing 10,000 kWh of energy a year, the Powerwall would lose 250 kWh, while the PWRcell would lose 350 kWh. That’s 100 kWh more saved with the Powerwall, which could mean noticeable cost savings on your electricity bill. 

Higher efficiency means you’re making the most out of your solar power, reducing your reliance on the grid and cutting down on carbon emissions. So, while the 1% difference might seem small, it can have a significant impact over the long haul. Just keep in mind that this is one piece of the puzzle. You’ll also want to consider capacity, scalability, and your specific energy needs when making your decision. 

Battery Capacity and Scalability Options

Capacity and scalability are vital, especially if your energy needs change. The Tesla Powerwall 3 has a fixed capacity of 13.5 kWh per unit, which is suitable for many homes. But if your energy requirements grow, you can link up to 4 Powerwalls together, giving you a massive amount of storage.

The Generac PWRcell, on the other hand, is highly modular. It starts with 9 kWh and can expand up to 36 kWh by connecting multiple battery cabinets. This flexibility allows you to customize the system based on your specific needs, making it a scalable solution as your energy demands increase.

Depth of Discharge

When comparing the depth of discharge (DoD) between the Tesla Powerwall 3 and the Generac PWRcell, there’s a significant difference. The depth of discharge indicates how much of the battery’s capacity can be used before it needs to be recharged. 

The Tesla Powerwall 3 offers a 100% depth of discharge. This means you can use the entire battery capacity without worrying about damaging the battery. It allows you to maximize the stored energy, making it highly efficient for daily use and backup power needs.

The Generac PWRcell has a depth of discharge of 84%. This means you can use up to 84% of the battery’s capacity before needing to recharge it. While this is still quite good, it’s less than what the Powerwall offers. This difference means that with the Generac PWRcell, a portion of the battery’s capacity must always be reserved, reducing the amount of usable energy compared to the Powerwall.

Choosing a battery with a higher depth of discharge can be more efficient and provide more flexibility in how you use your stored energy. For homes with high energy demands or those that rely heavily on stored power, the Tesla Powerwall 3's 100% offers a clear advantage.

Durability and Expected Lifespan

Both systems are designed to be durable and long-lasting. The Tesla Powerwall operates efficiently in temperatures ranging from -20°C to 50°C, while the Generac PWRcell is rated for -10°C to 50°C. Both batteries use lithium-ion technology, ensuring a long cycle life and reliable performance over many years. 

The warranties for both systems reflect their durability. Tesla offers a 10-year warranty with a guarantee of at least 70% capacity retention after ten years. Generac also provides a 10-year warranty, though specific retention rates can vary by product series


When it comes to cost, the Tesla Powerwall starts around $10,500 for a single unit installed. Prices can vary based on location and specific installation requirements. The Generac PWRcell, on the other hand, tends to be more flexible in terms of pricing due to its modular nature. A fully loaded PWRcell system with six battery modules can range from $13,000 to $19,000, depending on the configuration and installation specifics. You can lower your costs with incentives like the 30% federal tax credit and local rebates available in your location. 

Installation and Maintenance 

Installation of the Tesla Powerwall 3 can only be done by Tesla-certified installers and can be completed relatively quickly. Tesla provides extensive support and regular software updates to ensure optimal performance and longevity.

The Generac PWRcell also requires professional installation, which can be more complex due to its modular nature. This system might require more initial setup time, but it benefits from Generac’s robust support network and reliable performance. 

Maintenance is generally low for both systems, thanks to their advanced technology and solid customer support. 

Compatibility with Existing Solar Systems

The Tesla Powerwall 3 is designed to integrate seamlessly with existing solar systems, thanks to its built-in inverter. It can be paired with major solar inverter brands, making it a versatile option for homeowners looking to enhance their current setup. 

Generac PWRcell is also highly compatible with various solar systems. It uses the PWRview app for monitoring and control, ensuring smooth integration with different brands of solar panels. Its modular design further enhances its adaptability, making it easy to expand as your energy needs grow.


Tesla Powerwall 3 

Generac PWRcell

Energy capacity 


9 kWh - 18 kWh (Installed in increments of 3 kWh)

Continuous power output 



Peak output 


4.5 kW - 9 kW

Round trip efficiency 



Depth of discharge 



Battery chemistry 

Lithium-ion (Lithium iron phosphate)

Lithium-ion (Nickel manganese cobalt)

Operating temperature 

-20°C to 50°C

-10°C to 50°C


Up to 4 units

Modular, up to 36 kWh with multiple cabinets


10 years with 70% capacity retention

10 years (retention varies by product series

Wrapping up 

Choosing between the Tesla Powerwall 3 and the Generac PWRcell comes down to your specific energy needs and preferences. In the end, both systems are excellent for energy storage and backup power. Your choice will depend on specific factors like your energy needs, budget, and whether you prefer higher efficiency or greater capacity and scalability.  The Powerwall is a fantastic choice if you need a high power output and seamless integration with existing solar setups, especially if you have a high energy demand. On the other hand, the Generac PWRcell offers incredible flexibility and scalability, making it perfect for homes with changing energy needs.

Both systems have their unique advantages, so consider what matters most for your home. If you’re still unsure which one to pick, why not get some expert advice? Reach out to us for a free, personalized solar quote today. Our team can help you find the perfect energy storage solution to maximize your savings and efficiency. 


What are the main differences between Tesla Powerwall and Generac PWRcell?

The main differences lie in their power output, scalability, and efficiency. The Tesla Powerwall 3 offers a continuous power output of 11.5 kW and a peak of 30 kW, with a round-trip efficiency of 97.5%. It’s a fixed capacity unit at 13.5 kWh but can be linked up to four units. The Generac PWRcell offers 7.6 kW of continuous power, is highly modular with capacities from 9 kWh to 36 kWh, and has a 96.5% efficiency.

What is the warranty for Tesla Powerwall and Generac PWRcell?

How do these systems integrate with existing solar panels?

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