home battery comparison

Home battery comparison: Tesla Powerwall, Generac PWRcell, LG Chem RESU, sonnen eco

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Now more than ever, home batteries are becoming a smart purchase either with or without a solar panel system. Batteries offer many benefits, from electricity bill savings to resiliency against grid outages and more.

There are plenty of companies offering energy storage solutions, including both established manufacturers and up-and-coming smaller players offering unique products. In this article, we’ll review some of today’s most popular home battery options to see what sets them apart.

How to compare home batteries

When comparing options for home batteries, there are a few key data points to keep in mind: size, warranty terms, and price. While these aren’t the only factors to consider when shopping for a battery, they’re a great place to start and can help you better understand the costs and benefits you’ll get with each option.

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Size

When we talk about the size of solar batteries, we’re referencing two metrics: usable capacity and power. Power (measured in kilowatts, or kW) determines the maximum amount of electricity that can be output at a single time, while usable capacity (measured in kilowatt-hours, or kWh) is a measure of the maximum amount of electricity stored in your battery on a full charge.

You can think about these key size metrics like water running through a pipe. Usable energy capacity is the volume of water available to push through the pipe, while power is the size of the pipe. Larger pipes let more water flow through at one time, which depletes the total water stored faster. Similarly, a battery with high power can deliver more electricity at one time but will spin through its available energy capacity faster too.

A battery’s power determines what appliances you’ll be able to run with it all at the same time, and usable capacity determines how long those appliances can keep running on the battery. Batteries with a higher power rating can power more energy-hungry appliances or many appliances at once, while batteries with a higher usable capacity can store more total energy and thus can keep appliances running for longer periods of time without needing a recharge.

Warranty

In general, batteries will come with a capacity warranty, which guarantees that a certain percentage of the original battery energy capacity will remain after a set period of time (often 10 years.) In addition, some batteries have one of two other types of warranty: a throughput warranty (usually measured in megawatt-hours, or MWh) and a cycle warranty (measured in full charge/discharge cycles). Throughput warranties add a limit to how much energy you can cycle through your battery within the warranty period while remaining eligible for the guaranteed energy capacity warranty. Cycle warranties are another way to measure the time bounds on a warranty period – they specify the number of times you can charge and discharge your battery before the warrantied capacity is no longer applicable.

Price

Price is another important factor to consider when evaluating your home battery options. Similar to comparing prices for solar panels, there’s a difference between the cost of the equipment itself and the cost of a full system installation. Additionally, solar battery installation prices can depend heavily on your property – for example, your electrical panel setup and existing wiring might mean more or less work for an installation crew. As such, the actual “price” for installing a solar battery is different for everyone. We’ll compare the batteries below on their list price if it’s available.

Comparing popular home battery options

As batteries become more and more common around the country, new products and manufacturers are constantly emerging. Four of the most widely-known battery manufacturers today are Tesla, Generac, LG Chem, and sonnen. Read on below to learn more about each of these manufacturers’ key battery offerings.

Tesla Powerwall

Key metrics

  • Usable capacity: 13.5 kWh
  • Power: 5.0 kW
  • Warranty: 10 years, 70% capacity
  • Price: $7,600 before installation

Perhaps the most recognizable home battery available, the Tesla Powerwall has been a favorite for shoppers since the product launched in 2015. The Powerwall is a lithium-ion battery designed to be paired with solar panels, but can also be a standalone battery for home backup without solar.

The Powerwall has a companion app for your smartphone that you can use to manage your home energy system wirelessly. It has built-in software that helps you automatically optimize your energy usage patterns to take advantage of time-of-use rates in places like California, where the time of day you use or produce electricity has a big impact on your overall savings.

The Tesla Powerwall is a modular battery, meaning that while Tesla only offers one size of their battery, you can stack multiple together to create a larger storage system. The Tesla website indicates that you can add up to 10 Powerwall units together.

Check out our full review of the Telsa Powerwall for a more in-depth breakdown of their product.

Generac PWRcell

Key metrics

  • Usable capacity: 8.6 kWh to 17.1 kWh
  • Power: 3.4 kW to 6.7 kW
  • Warranty: 10 years, 22.6 MWh to 45.3 MWh
  • Price: $9,999 and up before installation

Generac has been in the energy backup business for many years with their staple gas generator products, but with their acquisition of battery manufacturer Pika Energy in 2019, they’ve entered the home battery market and added the PWRcell home battery to their product lineup. 

One of the hallmarks of the PWRcell (and before the PWRcell, Pika’s battery products) is its high instantaneous power rating. The PWRcell has the ability to provide instantaneous, or surge, power at a higher rate than most other batteries. This means that it’s able to handle sending a large amount of energy in a single instance to start appliances that require more instantaneous power to start up than continuous power to keep running, like an air conditioner.

Like the Powerwall, the PWRcell has a companion app (called PWRview) that lets you review all of your energy and savings metrics right from your smartphone. 

Check out our full review of the Generac PWRCell for a more in-depth breakdown of their product.

LG Chem RESU

Key metrics

  • Usable capacity: 9.3 kWh
  • Power: 5.0 kW
  • Warranty: 10 years, 60% capacity, 27.4 MWh throughput
  • Price: About $5,000 before installation

LG Chem is the chemical subsidiary of LG, one of the world’s largest electronics companies. Their battery product, the RESU 10H, has been one of the most popular residential batteries for many years. 

While LG Chem only offers one size of battery, they say you can combine batteries in a modular system to create a larger storage setup. However, they also recommend that you wire no more than two RESU batteries together in parallel. The LG Chem RESU is compatible with a wide range of battery inverters, which makes it easier to pair with and potentially easier to install. While it may not come with all of the bells and whistles some of LG’s competitors offer, the RESU battery is a time-tested, reliable home battery option that remains popular due to its dependability and cost. 

Check out our full review of the LG Chem RESU for a more in-depth breakdown of their product.

sonnen eco

Key metrics

  • Usable capacity: 4 kWh to 16 kWh
  • Power: 4.5 kW to 9 kW
  • Warranty: 10 years, 70% capacity, 10,000 cycles
  • Price: About $10,000 and up before installation

Typically seen as a more expensive, luxury battery product, the sonnen eco is also an established battery manufacturer with worldwide operations. Perhaps more than any other home battery on this list, the sonnen eco is an intelligent full-home energy management system that can help you integrate your solar panel energy production with the usage in your home, all while factoring in grid prices and energy efficiency to help you save the most money possible.

The size to price ratio of the eco is lower than most options, but sonnen makes up for lost ground on pricing with functionality. You can even integrate with a smart thermostat or home energy monitoring system to fully automate and optimize your energy use. 

Check out our full review of the sonnen eco for a more in-depth breakdown of their product.

Other home battery options

These aren’t the only battery options available, but are some of the most popular and talked about. If you’re curious about other home batteries available to help you save money and optimize your energy use, we’ve written reviews of several other major products:

Adding energy storage technology to your home is a complicated process that requires electrical expertise, certifications, and knowledge of the best solar-plus-storage installation practices.

A qualified EnergySage-approved company can give you the best recommendation about the best home battery for your unique property. If you are interested in receiving competing installation quotes for solar and energy storage options from local installers near you, simply join the EnergySage Solar Marketplace today and indicate what products you’re interested in your profile’s preferences section.

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About Jacob Marsh

Jacob is a researcher and content writer at EnergySage, where he focuses primarily on current issues–and new technology!–in the solar industry. With a background in environmental and geological science, Jacob brings an analytical perspective and passion for conservation to help solar shoppers make the right energy choices for their wallet and the environment. Outside of EnergySage, you can find him playing Ultimate Frisbee or being ultra-competitive at a new, obscure board game.

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