Home Batteries Generac PWRcell Home Battery: An Expert Review

Generac PWRcell Home Battery: An Expert Review

by Know it All Solar Nerds

The Generac PWRcell is a home energy backup battery designed to deliver an excellent performance. This battery is sold by Generac, a company created in Welsh in 1959 which designs power generators and is currently based in Wisconsin. Generac integrates the PWRcell with its PWRgenerators and other products to provide homes with the best energy solutions to achieve energy independence.

Figure 1: Generac PWRcell + PWRcell Inverter – Source: Generac

This battery competes with the likes of the Tesla Powerwall, Sonnen solar battery, and Sunvault Sunpower’s Battery for the title of the best solar battery. If you want to know more about the Generac PWRcell, this article is for you. Here we explain the basics of the PWRcell, how it integrates with some of the best products from Generac, and review the PWRcell battery in detail. 

What is the Generac PWRcell?

The Generac PWRcell is a high-performance outdoor/indoor rate smart Energy Storage System (ESS) using Lithium-Ion (Li-Ion) technology. You can use this ESS to store clean energy in solar systems, or you could also generate power with the Generac PWRgenerator.

This battery is an irreplaceable component of the Generac Clean Energy Solutions, used to store solar energy to power off-grid homes or make homes with grid connections more resilient against blackouts. Coupling the PWRcell battery with the PWRgenerator and PWRmanager, further increases the energy independence of the house, making it resilient and flexible.

The Generac PWRCell can be used for self-supply, backup power, zero-export systems, or to reduce power costs by configuring the Time-of-Use (TOU) rates mode. Depending on the desired application, you can power off-grid solar homes or houses connected to the grid to either reduce costs or have simple backup energy storage.

Key Features of the Generac PWRcell

The Generac PWRcell is a battery with great performance, expandability, and adaptability to most situations, making it a best-in-class battery solution. Here are some of the key features of this battery:

  •  Rated 3R for indoor/outdoor installations.
  • Expandable capacity ranges from 9 – 18 kWh for a single battery cabinet or 36 kWh by including an additional cabinet.
  • Round-trip efficiency of 96.5%, 16.5% more than the average.
  • Can supply a continuous power surge of 11.40kW.
  • Can prioritize critical loads in the home.
  • Base price of $10,000 for the 9kWh PWRcell.
  • Can reduce monthly electricity bills through TOU tariff optimization.
  • Suitable for residential and commercial usage.

How Does the Generac PWRcell Work?

Many  PV systems use single module DC optimizers; however, the Generac PWRcell works under the PWRzone system. This system uses a PV Link substring optimizer featuring Maximum Power Point Tracking (MPPT) technology that sends the highest possible solar panel output power to the inverter to charge the battery. The battery also features a SnapRS device for safety compliances.

Figure 2: Operability of the MPPT technology in the I-V curve – Source: Virtual Renewable Energy Laboratory

The PV link is a 2,500W power optimizer using cutting-edge MPPT algorithms that find the best voltage and current in the I-V curve (figure above) to deliver the best power output for each string. Systems using the PV link can have strings with different capacities connected to the same inverter. The SnapRS is a simple module-level shutdown device that operates in compliance with the 2017/2020 NEC 690.12.

(a)

(b)

Figure 3: Connection of a Generac PWRzone (a). Generac PWRcell solar plus battery storage connection – Source: Generac and PWRcell brochure

The PWRcell battery can get fully charged using the PWRzone system that ensures arrays with different capacities and shadings get the best power output for the panels. This means a higher credit count in the net metering system. A full battery will make off-grid homes more resilient for night times with higher power consumption or days with low solar radiation, and it also helps battery-backed solar homes be action-ready for blackouts.

During a power outage, combining the PWRcell with the Smart Management Modules (SMMs) or PWRmanager can help prioritize critical loads for the home, ensuring smarter energy usage. This will help extend the backup time for the battery and prevent the inverter from overloading.

The PWRcell battery can also help reduce monthly electricity bills in states like California since it is optimized for TOU tariff rates. You can do so by delivering power to the home or selling it to the grid during high-demand peak hours when higher tariffs are active. You can also choose to consume energy from the grid or the battery during off-peak hours with lower electricity costs.

To further increase the energy resilience of your home, you can acquire the Generac PWRgenerator. This is a propane/natural gas generator designed to use fuel efficiently and run at low sound levels of 61 dB. The PWRgenerator can charge the PWRcell battery with a maximum continuous power capacity of 9,000W, extending the backup power time for the home. 

Review of the Generac PWRcell

The Generac PWRcell is an excellent way to make your home energy independent. If you want to know more about the Generac PWRcell, in this section, we review some of the best features and specifications of the battery.

Usable Energy + Expandability of the PWRcell System

One feature we like the most from the Generac PWRcell battery is its usable energy and how it suits the needs of the different homeowners. The PWRcell battery has a base capacity of 9kWh, which includes 3 Li-Ion battery modules of 3kWh each, but you can expand its capacity as you see fit.

The PWRcell battery cabinet can be expanded by adding 3kWh modules, up to 6 modules in total, with a maximum storage capacity of 18kWh per cabinet, which is more than what the Tesla Powerwall offers (Figure below).

Figure 4: Usable Capacity (kWh) of the Generac PWRcell vs. Competition – Source: Solar Alternatives

If 18kWh is not enough, you can also couple two PWRcell battery cabinets together. This would increase the total capacity of your Generac PWRcell system to a total 36kWh.

 

Rated and Peak Power of the Batteries

The rated and peak power you can demand from the battery increases with every added battery module, and it is ultimately limited by the PWRcell inverter. A PWRcell with 3 battery modules can supply a continuous power demand of 3.4kW or a maximum peak demand of 4.5kW. In comparison, 6 battery modules handle a continuous power demand of 6.7kW and a maximum peak demand of 9kW.

A grid-tie single-phase PWRcell inverter limits the power output to 7.6kW, while connecting the inverter off-grid can increase the power output to 9kW. Using a three-phase PWRcell inverter further increases the power output to 11.4kW for grid-tied configurations or 9kW for off-grid connections. Both inverters in off-grid configuration can deliver 11.00kW when coupled with two PWRcell battery cabinets.

What is the Maximum PV System Size for the PWRCell?

You should always consider the limiting specifications for the PWRcell battery and inverter when installing a PV system. Generac recommends using a maximum PV system of 10 kWp for homes using a single-phase or a PV system with a generation capacity of up to 15 kWp for a home three-phase home.

Considering high-quality PV modules with a capacity of 400W per module, the largest system you could install for a single-phase home includes around 25 modules. A house with a three-phase connection can have a PV array with up to 37 x 400W PV modules for a PV capacity of 14.8 kWp.

Operating Temperatures + Installation Rating

Another exciting aspect of the Generac PWRcell battery is the installation rating. Most Generac solar products like the PWRcell battery, PV link, PWRgenerator, and others are 3R rated, making them suitable for indoor/outdoor installations. 

 

Figure 5: Average temperatures in California – Source: Weather Spark

For a PWRcell battery to work in optimal conditions, we recommend paying attention to the outdoor/indoor installation temperatures. The PWRcell battery can operate at 14ºF (10ºC) to 122ºF (50ºC), but its optimal operating temperature ranges from 41ºF (5ºC) to 104ºF (40ºC). This means that a PWRcell battery in California works close to optimal conditions throughout the year (figure above).

How Good is the Warranty of the PWRcell Battery?

Another aspect that we like about the PWRcell battery is the warranty. Most Li-Ion batteries have a standard warranty of 2 years, and very few extend a few more years, but the PWRcell battery warranty greatly surpasses those warranties.

Since the PWRcell is a high-quality and durable battery, Generac backs up the Li-Ion modules with a 10-year warranty or a power output of 7.56MWh per module (whichever comes first) throughout their lifespan. This means that if your battery has 6 modules, the warrantied energy is 45.36MWh or 10-yr, which is roughly equivalent to 3,150 cycles at an 80% Depth of Discharge (DoD) or 2,520 cycles at a 100% DoD. The electronics and enclosure also have a 10-year warranty. It is noticeable that compared with other battery models, the guaranteed energy throughput is not as high.

What Solar Incentives Can I Apply to With the Generac PWRcell?

Solar homeowners in California can ask for the Self-Generation Incentive Program (SGIP) incentive, which is one of the best California solar rebates, covering from $850 to $1000/kilowatt-hour or 85% to 100% of the cost for the ESS. A 9kWh Generac PWRcell system has a base price of $10,000, meaning that the incentive could cover $8,500 or even the full extent of the cost for the system.

Conclusion: is Generac PWRcell the Right Choice For You?

The Generac PWRcell is one of the most versatile ESS available for homeowners. You can acquire it with a regular capacity of 9kWh or increase it up to 36kWh. This battery is ideal for self-supplying, backup power storage, zero-export, or reducing electricity bills under the TOU rates, making it excellent to provide energy independence, costs reductions, and resilience against power outages.

On top of being one of the best home batteries, the Generac PWRcell integrates seamlessly with other Generac products. It also manages and prioritizes the load for your home, providing you with the capacity to extend battery usage, protect the inverter, and even generate more power with the PWRgenerator.

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