How Does Solar Plus Battery Backup Work?

A home battery acts as a barrier between your home and the utility. The battery plugs into your home's electrical system to optimize your daily energy usage during peak demands times, and to provide backup power during a utility power outage. It does this by taking in electricity from the grid or captures and stores electricity from solar panels and then using it in your house to save you money.

As with all home battery products, the Generac PWRcell energy storage system is sized for your day-to-day use at your home and your specific loads that you wish to be offset. Generac PWRcell is designed to be used in conjunction with a solar energy system.

During sunny days your solar panels produce more electricity than the home can use, the excess is collected in the battery, instead of the excess spilling back to your local utility. Then, in the evening, when your solar panels aren't producing electricity, the stored electricity in your battery is used instead of buying it from your utility company.

What Makes Generac PWRcell Different?

In conjunction with Generac PWRcell, Generac offers its energy monitoring system, known as PWRview. This mobile app, PWRview, shows detailed bill tracking and forecasting, as well as enabling you to set daily and monthly goals on electricity consumption within the PWRView app.

When comparing the PWRcell to other home batteries, there are two things to pay attention to. The first specification to know is the battery size, which is shown in the power and capacity, the second is round trip efficiency, and depth of discharge (more on this below).

After the product first launched in September of 2019, it was described as a;

"truly scalable storage system with unmatched raw power."

What is the Maximum Storage Capacity?

As mentioned above, two important metrics to compare the Generac PWRcell to other products are energy storage capacity and power.

Power, which is measured in kilowatts, or kW, determines how much electricity can be used at a particular time.

PWRCell inverter and battery storage system by Generac.

In contrast, usable capacity is measured in kilowatt-hours or kWh. This measures the amount of electricity stored in your battery and gives you the kWh for your battery when it is fully charged. The PWRcell 17 is the biggest single battery unit that Generachas produced, exemplified by its 17.1 kWh of usable electricity capacity and maximum power rating of 6.7 kW.

PWRcell also provides homeowners with enough power and capacity to cover a surge capacity sufficient enough to start large loads such as air conditioners, well pumps, and furnaces. Once running, the PWRcell provides 8 kW of continuous power. Which can be expanded as more power or capacity is needed, additional PWRCell inverters and battery modules can be added to produce as much as 34.2 kWh of DC-coupled stored energy.

A battery's power directly correlates to the number of appliances you can run from the battery at once. In contrast, usable capacity determines how long those appliances can operate. Batteries with higher power ratings are more capable of powering multiple, large devices, such as your HVAC system, well pump, furnace, or many appliances at once, such as your lights and electrical outlets in your home.

What Equipment is Involved?

Generac offers both hardware and software products designed to provide the most widespread solution for customers looking for Solar+Battery Storage. The two main components are a solar inverter, which is paired alongside their PWRcell battery.

PWRCell Inverter

The inverter acts as both a battery inverter and a solar array inverter. This means that it will be able to provide power for your home when the utility grid goes out, as well as transition to and from with your solar system with no interruption.

PWRView App

The next component is monitoring, PWRcell is one of the few to build this component into the inverter itself, this component is known as PWRview. Purview can be accessed from all your devices, allowing you the ability to see your home’s consumption even when you’re away. With the unified inverter and monitoring, PWRcell can easily manage your home's electricity loads and pulls energy from the battery as it is needed.

PWRCell Performance

Evaluating the production of a battery means identifying two components, first the batteries’ depth of discharge (DoD), which is the percent the battery has emptied relatively to the batteries maximum storage capabilities. Do to how batteries charge, discharge, and re-charge, battery life decreases each time it cycles.

Most battery manufacturers indicate a maximum DoD level to maintain optimal battery performance. As a general rule, batteries with higher DoD are considered more top quality products. The Generac PWRcell it has a DoD of 84%.

Second, roundtrip efficiency measures the electrical losses related to the charging and discharging of a battery. The higher the efficiency percentage, the more efficient the battery is at converting incoming electricity into usable power in the battery. PWRcell has one of the highest round trip efficiency indicators in the industry.

With PWR’s efficiency percentage of 96.5; this means that if your solar array produces 10 kilowatt-hours (kWh) of electricity and this is ported to the battery, you'll get 9.65 kWh of clean energy available for use when you need it.

PWRCell Costs

Battery costs are only one piece of the pie when thinking of home energy solutions. A solar array plus a home battery storage system are not inexpensive purchases, but the price is entirely dependent on where you live and the equipment you choose to use. The cheapest option for a PWRcell system is the 8.6kWh system, but this is scalable up to 17.1kWh with just one battery, allowing matching to any budget. The best way to get a realistic estimate is to contact a battery specialist here at Sunbridge Solar.

Generac PWRCell combined inverter and battery storage system.

Quick Summary

PWRcell by Generac

The battery system can be equipped with 8.6kWh batteries, and that can expand up to 34.2kWh on one inverter.
A single inverter for grid-tied solar with smart battery integration.
Easy to install, while providing backup power and helps users save on energy bills.
The system consists of a storage cabinet, battery pack, inverter, and associated hardware.
Easy monitoring with PWRview.

PWRview App

Simple to install
Users better understand their consumption with the ability to monitor energy use
Detailed electricity bill tracking
Intuitive bill forecasting
Useful tips to help lower monthly bills