Tesla Powerwall 2 vs. LG Chem RESU 10H Introduction:
It is sometimes shocking to think about how fast solar energy has grown in the United States over the past two decades. If you live in California or Hawaii, all you have to do is look around your neighborhood, and chances are high you will see solar panel installations. Part of this growth and the future progress of residential renewable energy is connected to home solar batteries. The two leaders in this space are the Tesla Powerwall 2 and LG Chen RESU 10H.
Both the Powerwall 2 and the RESU 10H have been installed at scale across the nation, and when homeowners are exploring adding a battery to the solar system, they are the two industry leaders that customers should consider.
Like any competitors, each product has strengths and weaknesses. We put together this guide to compare the Powerwall 2 and the RESU 10H so you can make an informed decision on the correct battery for you!
Key Product Details:
When looking at the two batteries, it is essential to set a baseline understanding of how the two batteries compare. To set a baseline for comparing the Powerwall 2 and the RESU 10H, let's look at the Battery Type, Cell Chemistry, Battery Size, Usable Capacity, Power Output, Warranty Length, and Capacity, and finally, the Price.
Tesla Powerwall Product Details:
Battery Type: AC Battery
Cell Chemistry: Lithium nickel manganese cobalt oxide (NMC pouch cells)
Battery size: 13.5 h in the US
Usable Capacity: 13.5 kWh of usable capacity
Power output - 5kW continuous
Warranty Length: 10 years
Warranty Rated Capacity Year 10: 70 percent retained capacity
Price: $12,000-15,000 depending on variables
LG Chem RESU Product Details:
Battery Type: DC Battery with a coupled system (48V and 400V options)
Cell Chemistry: Lithium nickel manganese cobalt oxide (NMC pouch cells)
Battery size: 9.8 h in the US (6.5kWh,13kWh, and 16kWh available in other markets)
Usable Capacity: 9.3 kWh of usable capacity
Power output - 5kW continuous
Warranty Length: 10 years
Warranty Rated Capacity Year 10: 60 percent retained capacity
Price: $9,500 -13,000 depending on variables
About Tesla and LG Chem:
When getting a home solar battery, it is important to know about the company that produces the battery! Both LG Chem and Tesla have been industry leaders in the storage space, but let's look at LG Chem and Tesla's history.
Tesla Company profile:
Tesla was founded in 2003 to develop electric sports cars. In 2004, Elon Musk joined the company, and over the past 17 years has helped guide the development of leading electric vehicles, the Tesla Model S, 3, X, or Y.
As the company focused on developing electric vehicles, it announced the Powerwall 1 for residential home-usage. In 2016 the Powerwall 2 was developed, and since its development, over 100,000 Powerwalls have been installed.
2020 was a year of significant financial growth for Tesla, when its valuation reached $500 billion, making it one of the world's most valuable companies. This substantial financial growth will allow Tesla to continue to develop new products and standby the product warranty for the Powerwall 2.
LG Chem Company profile:
LG Chem, Ltd. is a Korean company that has been a global leader in various fields since its founding in 1947. LG Chem has grown to become one of the largest chemical and battery companies globally, with over 29,000 employees worldwide.
During the past two decades, batteries have increasingly become a part of everyday life. LG Chem identified this early and focused its energy on developing lithium-ion batteries. As a result, LG Chem has become one of the globe's largest producers.
This focus has lead LG Chem to yearly sales that exceed $22 billion and future projections. The leadership LG Chem has on the production of batteries for EV manufacturers worldwide will allow LG Chem to improve battery technology and provide warranty coverage for the RESU 10H.
When installed with a residential solar system, home residential batterie are designed to accomplish two primary purposes. The first purpose is to provide backup power during a power outage. The second is to help offset utility rate structures, where the cost of power is more expensive during certain times of the day.
Battery type: AC vs. DC battery systems
When it comes to how a solar panel system, the inverters, and home batteries are connected, homeowners have two options: they can go with an alternating current (AC) coupled system like the Powerwall 2 and or a direct current (DC) coupled system like the LG Chem RESU 10H.
Both AC and DC coupled systems will store energy for deployment when the home needs it, but they differ in how the electricity flows from the solar panels into the battery and eventually into the home. Solar panels produce DC electricity, this DC electricity must be inverted into AC electricity used in American homes. With a standalone solar system, this process takes place using a solar inverter.
Home solar batteries store electricity in the DC form.
In an AC-coupled system, like the Tesla battery, the DC electricity created by the solar panels flows into a solar inverter to be inverted into AC electricity. At that point, the electricity can flow into your home or flow through another inverted, to transform it back into DC electricity to be stored in the battery. When the home needs to pull power from the Powerwall 2, the DC electricity is inverted one more time back to AC to be used in the home.
When designing the Powerwall 2, Tesla decided to design an AC coupled system because it allows for a more flexible installation. AC coupled systems work with a larger number of solar inverters and are easier to retrofit onto solar systems that have been designed without batteries.
Battery efficiency: How do the Powerwall and RESU 10H Compare?
The drawback with AC coupled batteries is that the process of inverting the electricity three times reduces its efficiency. As a result, the Pwoerwall 2 has a round trip efficiency of 90%.
DC-coupled battery systems like the LG RESU 10H are a bit simpler. The DC electricity produced by the solar panels flows directly from the solar into a charge controller that flows directly into the battery. When the home is ready to pull electricity from the battery, it is inverted into AC electricity used in the home.
Because the electricity only needs to be inverted once, the RESU 10H is more efficient, with a roundtrip efficiency rating of 94.5%.
Like other DC-coupled battery systems, the LG Chem requires specific types of solar inverters to be able to work. By requiring specific inverter partners, LG Chem can be limited in its design and ability to be installed with previously installed solar projects.
When thinking about a battery's capacity, one way to think about it is like a water or gas tank. The larger the size, the more power it can hold.
Another important real-world factor that many battery companies do not share is the usable battery capacity. To protect battery life, many battery manufacturers limit the percentage of electricity deployed from a battery. Some battery companies do not share this information, leaving consumers in the dark about the actual usable capacity of a battery.
Because of its focus on developing efficient batteries for its line of cars, the Model S, Model 3, Model Y, Model X, Tesla Roadster, and Cybertruck (learn how long it takes to charge a Tesla), the Powerwall 2 has a very impressive capacity of 13.5 kilowatt-hours. In addition to its large size, the Powerwall 2 has 100% usable power because of its 100% depth of discharge. For the home battery market, the Powerwall is one of the most prominent economically viable home energy storage solutions.
LG Chem examined the needs of homes and built it's battery based on what it thinks the average home will need. RESU 10H has a listed size of 9.8 kilowatt-hours (kWh), with a usable depth of the discharge of 95%. As a result of the 95% depth of discharge, the battery has a usable capacity of 9.3 kWh.
For homeowners with larger battery needs, the Powerwall 2 and LG Chem can be combined to expand the storage capacity. 9 Powerwall 2s can be combined in one system and 2 LG Chem RESU 10Hs can be combined.
Peak Power and Continuous Power:
For batteries to accomplish the goals of providing backup power and help with Time-of-use rate structures, the battery needs to be able to deploy electricity in two specific ways. The battery needs to provide a large but short jolt of power, known as the peak power, this is especially important in a power outage situation.
Both the Powerwall 2 and LG Chem can deploy 7kW of peak power.
The other important factor for homes with home battery systems is how much power the battery can provide continuously or its continuous rate. When batteries need to be used for a more extended period, like in a time-of-use situation, the continuous rate is critical. Both the Powerwall 2 and LG Chem have a 5kW continuous rate.
Powerwall 2 and RESU 10H Connectivity:
Batteries on their own cannot do anything besides store electricity. By connecting them to the internet and adding some additional equipment, batteries can be programmed to operate in different ways to improve home batteries' functionality.
The ways that the Powerwall 2 and LG RESU connect the batteries to the internet are different.
Powerwall 2 Gateway:
The Powerwall Gateway 2 is the brains of the battery. It functions to keep the Powerwall 2 connected to the internet at all times. This connectivity allows the battery to be optimized for backup power or utility optimization. It also allows the battery to be updated over the air to help the battery remain updated as new functionality is needed in the future.
Tesla understands the importance the Powerwall plays in the long-term functionality of the Powerwall, and in 2019 Tesla upgraded to the Powerwall Gateway 2. The Powerwall Gateway 2 is a marked improvement from the first generation of the product for various reasons.
The Powerwall Gateway 2 is designed to be a more aesthetically pleasing product and looks like a miniature version of the Powerwall 2. To improve internet connection and avoid communication breakdowns, the Gateway 2 has cellular, WiFi communication, and an ethernet plug inside in case of emergency.
LG Chem RESU 10H Connectivity:
Instead of designing a dedicated component to keep the RESU 10H connected, LG Chem chose to partner directly with solar inverter companies to provide battery management and connectivity. The connectivity provides the ability to update the battery's functionality, protect the battery's life, and maximize savings based on utility rate structures. LG Chem has partnered with industry leaders on the inverter side.
LG Chem Inverter Partner
1) SolarEdge StorEdge
2) SMA Sunny Boy Storage
Powerwall 2 and LG Chem Operating Modes:
Home solar batteries are products that homeowners look at because they have specific requirements. Most homeowners are looking to protect themselves against power outages and increase the financial return on investment by adding solar panels.
To accomplish this, the Powerwall 2 and, when combined with an internet-connected solar inverter, the LG Chem, have different operating modes to deploy the electricity stored in the batteries.
Let's review the Powerwall 2 and LG Chem's operating modes to see how they address homeowner's needs.
Powerwall 2 Operating modes:
Tesla understands the importance of adjusting battery functionality overtime. As a result, they developed over-the-air updates that are similar to the functionality that Telsa automobiles utilize.
Ensuring the Powerwall 2 is always connected to the internet is done via the Powerwall Gateway. The Gateway, allows the Powerwall 2 to adjust how it deploys electricity based on the cost of power, utility policies, and the likelihood of a power outage. By leveraging the available data from the deployed Powerwalls, a homeowner can pick from a few optimized settings to get the most from their Powerwall 2.
Self-Powered — When in the Self-Powered mode, Powerwall 2 is designed to maximize the home's self-consumption. Self-consumption is designed, so the home utilizes the most power produced by the solar panel system and the least produced by the electric company.
To accomplish this, during the day, the Powerwall 2 is first filled with solar power before the solar energy flows into the house. At night, the stored energy is deployed from the battery into the home, limiting the need to pull electricity from the utility grid.
The Powerwall 2 can set aside energy to be available in a blackout situation. When set up for Self-Power, the battery can keep a reserve of anywhere between 0-100%.
Backup-Only — With the recent power outages in Texas, the forest fires that have impacted California customers in Pacific Gas and Electric, San Diego Gas and Electric, Southern California Edison, and other natural disasters, many homeowners are looking at residential batteries, are doing so to provide backup power during a utility outage.
The Powerwall 2 can provide full home backup power. The ability to do full home backup is an important feature, especially when combined with the fact that when solar is combined with a Powerwall 2, it can also power the home during the day. This function allows for solar and the Powerwall 2 to power the home during an extended blackout regardless of if the outage goes on for hours, days or weeks.
Advanced Time-Based Control — Utilizing its internet connectivity gives Powerwall 2 the ability to optimize when it deploys electricity to help optimize the value of the electricity produced and stored by the solar system. The battery intelligently charges and discharges when the price depending on the cost of electricity. This ability is vital in utilities with a time of use rate structures like in California under NEM 2.0.
Within the Advanced Time-Based Control, Tesla gives homeowners two options a balanced mode or a cost savings mode.
Balance mode focuses on the solar and battery system utilizing stored solar power in the home when electricity from the Utility is at its most expensive and when the sun goes down.
The Cost Saving mode is designed to utilize the battery's power to minimize a home's utility electrical usage and reduce the amount of utility electricity a home uses as much as possible.
Tesla has focused on expanding Powerwall 2 functionality, and they have developed modes designed for specific geographic locations.
Grid Services — Grid services are programs between utilities and homeowners that allow utilities to pull power from a homeowner's battery in exchange for compensation. The utilities set up these programs to help stabilize the power grid, limit the likelihood of power outages and limit the need to turn on expensive power plants.
Because of our partnership with Sunrun, the Powerwall 2 can be utilized in Grid Service programs like the Kukui Hele Pō in Hawaii.
Storm Watch — Because the Powerwall 2 has live updates coming to it from its internet connectivity, the Powerwall can automatically charge the battery if it senses that a storm is approaching the home. Storm Watch can fully charge the battery so that if a power outage does occur, the home will have the maximum amount of backup power.
The homeowners do have the ability to deactivate this functionality if desired.
LG Chem operating modes:
As we covered in the connectivity segment, LG Chem has designed the RESU 10 to be connected to the internet via different solar inverters. When paired with the correct solar inverters, the RESU 10 can also work in different ways to address homeowners' specific needs. The LG Chem RESU has three main operating modes battery backup power, utility optimization, or a combination of both.
Backup-Only— Most customers looking to add a solar battery are doing it to protect themselves against power outages. The RESU 10H was engineered and designed with this purpose at the forefront. When combined with an appropriately sized solar panel system, the RESU can provide partial home battery backup. In Backup-Only, the RESU 10 can reserve 0-100% of available power for backup functionality.
Utility Optimization— Utilizing the inverter's connectivity, RESU10 can store power from the solar system and deploy it into the home or grid to maximize the solar's economic investment. This function can provide massive financial advantages in utilities with a time-of-use rate structure like California utilities San Diego Gas & Electric (SDG&E), Southern California Edison (SCE), and Pacific Gas & Electric (PGE) under NEM 2.0.
Backup and Utility Optimization— Many homeowners who add energy storage are looking to accomplish both Backup functionality and Utility Optimization. By utilizing the internet connectivity that the inverters provide, the RESU 10 can provide both backup power and utility optimization to protect against utility rate structure changes.
Tesla Powerwall 2 and LG Chem RESU 10H Battery Chemistry:
Over the past few decades, investment in battery technology has increased significantly. As more handheld appliances (phones, tablets, etc.) and large-scale products (electric vehicles, home batteries, etc.) run on electricity, the need for more efficient and longer-lasting batteries has increased.
LG Chem and Tesla have been at the forefront of investment and development in the home battery space.
In the end, both companies use similar battery chemistry, lithium-ion battery chemistry. More specifically, the Powerwall 2 and LG Chem RESU 10H use lithium nickel manganese cobalt oxide (NMC) battery. LG Chem and Tesla use this chemistry because, at their price point, LFP batteries have some of the highest energy density (the amount of energy stored in physical space) and the best safety of any battery chemistry.
If you would like to learn more about the different residential battery types, check our guide to residential battery types.
Installation and Technology Advantages:
We have covered many ways that the Powerwall 2 and the LG Chem Resu 10H are similar, but each product has some technology and installation-based differences.
LG Chem: Homeowners needs first and foremost
When LG Chem looked at the home solar battery space, they identified that most consumers want a battery that can power critical loads in the home overnight. As a result, they have focused the product on making it as easy as possible to install and as reliable as possible as a battery backup solution.
RESU 10H Function:
The LG Chem is designed to backup eight critical loads within a house. Unlike the Powerwall 2, the LG Chem does not back up the entire home.
This was an intentional decision meant to extend the amount of time the battery can backup the home's critical loads. LG Chem feels that many electrical circuits in the home are not necessary for an extended power outage. By limiting the number of circuits backed up, LG Chem can help homeowners keep the power longer during more extended blackouts.
LG Chem Installation:
Batteries can be hefty, making them very challenging to install. LG Chem focused on reducing the footprint and size of the RESU 10H, helping installers get the product installed faster, and allowing for more flexibility on the location of the RESU 10H.
The RESU 10H weighs 214 (98 kilograms) or 220 pounds (100 kilograms), depending on the inverter it uses. It has a height of 35.7 in x width of 29.7 in x depth of 8.1 in (907 mm x 755 mm x 155 mm), allowing flexibility on the installation location.
Most LG Chems are wall-mounted to protect the battery from temperature fluctuations or limit anything hitting the battery.
Because of its focus on maximizing battery performance, the RESU 10H has a broad optimal temperature range. The LG Chem functions best between 59°F to 86°F (15°C and 30°C). The LG Chem can still function between 14F to 113°F (-10°C to 45°C), but in extreme temperature, the lifespan or efficiency can be impacted. Because of the importance of maintaining the optimal temperature range, installing the product in a garage may make sense if you live in a location with more extreme temperature swings.
Powerwall 2: Technology Development and Full Home Focus
Tesla has utilized its research to develop a better car battery to improve Powerwall 2. One thing that Tesla identified is that preconditioning a battery can help it perform at a higher level.
Tesla designed the Powerwall 2 with a full liquid thermal management system. The liquid cooling system is fully enclosed and circulates 2.4 quarts (2.3 LO) of liquid coolant to ensure that no matter what the outside temapture is, the battery will be more likely to stay close to its ideal temperatures.
This thermal management allows the battery to operate at the broadest range of temperatures for a residential battery -4°F to 122°F. It also helps protect the battery because temperature swings can harm a battery's efficiency, reducing useable storage and lifespan.
Powerwall 2 uses its internet connectivity to help manage the battery's temperature with the liquid thermal management system. The Powerwall 2 can start warming up or cooling down before the sun comes up to adjust the battery to its ideal temapture.
Powerwall 2 Installation:
Tesla is always trying to push battery technology forward as part of its mission to transition to a more electrified future. As a result, Tesla has designed the Powerwall 2 to be capable of full home backup. The Powerwall 2 ability to do whole home is determined by a home's electrical panel and voltage of the house's appliances. To allow the Powerwall 2 to work for as many homes as possible, it is also possible to only backup up dedicated loads in a home.
When installing the Powerwall 2, the battery can either be ground-mounted or mounted on the wall. It is usually recommended that a location be picked for the battery to keep it as close as possible to the electrical panel.
Because of the battery's external casing and the cooling system, the Powerwall 2 is touch-safe, water-resistant, and dustproof. This allows more installation flexibility and helps to avoid the need for special clearances or safety measures.
The Powerwall 2 is a weighty product that usually requires multiple crew members to install. The Powerwall 2 weighs 269 pounds (122 kilograms). It has a height of 45.3 in x width of 29.7 in x depth of 6.1 in (1150 mm x 755 mm x 155 mm).
Depending on what the use case for the battery will be, additional electrical equipment or adjustments to the electrical panel might be needed. If the battery is used as a backup power source for essential loads, the installers will need to install a new sub-panel to connect the Powerwall 2 to the specific circuits in the home that it will backup during an outage.
Warranty: How the LG Chem and Powerwall 2 warranty compare?
The philosophy behind how LG Chem and Tesla have set up their products' warranty is slightly different. Tesla has focused its warranty more on the length of time, while LG Chem is focused more on the amount of electricity output.
When comparing the warranties, it is also essential to consider Tesla and LG Chem's financial standing.
Let's take a look at the warranty of the RESU 10H and the Powerwall 2, so we can compare the two.
Tesla Powerwall 2 warranty coverage
Warranty period: 10 years
Guaranteed end of warranty capacity: 70%
Tesla took a look at the lifespan of its batteries and the expected efficiency of the product. As a result, Tesl provides a 10-year warranty on the Powerwall 2 and guarantees that it will maintain at least 70 percent of its ability to hold a charge through those ten years.
Tesla experienced massive financial growth in 2020, and that trend continued into 2021. That financial growth is significant because some experts had concerns about the long-term financial stability of Tesla in the past. Tesla's financial strength helps lead to confidence for Powerwall 2 consumers that the product warranty will be upheld by Tesla.
LG chem RESU 10H warranty coverage:
Warranty period: 10 years or 22.4 MWh energy throughput
Guaranteed end of warranty capacity: 60%
LG Chem looked at the standard usage case of the RESU 10H when designing its warranty. When analyzing how the battery will be used, LG Chem identified that the battery would experience one cycle of charging and discharging a day. Because of this cycle analysis, LG Chem provides a warranty of 10 years or 22.4 mWh of energy throughput (this is the equivalent of a daily cycle for ten years). LG Chem's warranty also guarantees the RESU 10H will have at least 60 percent of its ability to hold a charge at the end of ten years.
Because of the focus LG Chem has had on developing a leadership position in battery production for electric vehicles, LG Chem had a great year in 2020 and is projected to do well over the coming years. The long-term expansion of the EV and home solar battery market is important to provide RESU 10H consumers with confidence in the warranty of the RESU 10H.
Price, Rebate, Incentives:
When making the financial decision on what battery to pick, it is not just the product specs and manufacturer that homeowners need to understand. It is also essential that they understand how LG Chem and Tesla are priced and what incentives are available.
Pricing: How do the Powerwall 2 and RESU 10H compare?
The Powerwall 2 is a slightly larger product and includes some additional functionality compared to the LG Chem RESU 10H. The Powerwall 2 on its own is around $6,500, and the Powerwall Backup Gateway 2 costs $1,100. Additional hardware, permitting, and installation costs usually cost around $3,0000-5,000. The product price will vary slightly based on location, but the cost of Powerwall 2 usually falls somewhere between $12,500 and $14,000.
The cost of installing the LG Chem also depends on a few different factors. The RESU 10H on its own usually costs around $5,500 and requires an upgraded solar inverter that usually adds around $500 of the cost. The additional cost of $4,500-6,000 usually covers additional hardware, permitting, and installation costs. When combined with a solar installation, installing the LG Chem RESU 10H usually costs between $10,500-$13,000.
Alchemy Solar is focused on expanding access to home energy storage as much as possible. We understand that the additional cost can be expensive for some homeowners. To ensure that as many homeowners as possible have access to Powerwall 2 and the RESU 10h, we work with Sunrun to provide $0 down Power Purchase Agreements, which requires no upfront cost to homeowners in specific markets.
LG Chem and Tesla Battery Rebates and Incentives
Batteries make additional financial sense in markets where the state, municipalities, or utilities provide additional incentives for homeowners with batteries. In markets like Hawaii, where utility rate structure make it less valuable to export power back into the grid, affordable solar batteries are an essential part of going solar.
The LG Chem or Powerwall 2 can be used on Oahu as part of Hawaiian Electric's (HECO) Kukui Hele Pō grid service program. As a result of our relationship with Sunrun, our customers on Oahu can enter a program that allows HECO to pull power from a homeowner's battery in exchange for compensation and other incentives (a one-time payment, a donation in the homeowner's name to a Hawaiin language school, and more!).
These grid service agreements help stabilize the grid and improve other homeowners' economic viability adding solar panel systems and home energy storage. They are becoming more and more common around the country, and homeowners who add batteries now will be able to take advantage of them in the future as they come online.
When charged with solar, both the RESU 10H and Tesla Powerwall 2 qualify for various rebates and, when charged with solar panels, the Federal Solar Tax Credit. For example, in California, some homeowners can qualify for the Self-Generation Incentive Program, reducing the cost of installing the battery significantly.
Homeowners in the three largest public utilities San Deigo Gas and Electric (SDG&E), Southern California Electric (SCE), and Pacific Gas and Electric (PG&E), will also see increased savings under Net Energy Metering 2.0 (NEM 2.0 as it is sometimes known). These utilities use a Time-Of-Use billing structure that charges homeowners different amounts for electricity at different times of the day. By storing cheap solar power and deploying it when electricity is the most expensive, both the LG Chem and Tesla batteries can help homeowners maximize savings under NEM 2.0.
Conclusion: What is the best battery, the LG Chem RESU 10H or Tesla Powerwall 2?
The best battery really depends on the needs of each homeowner. For homeowners looking for full home backup, the Powerwall 2 is the best battery. If the homeowner is looking for the most cost-effective battery, LG Chem is the right solution.
Like a solar panel system, every homeowner has different battery needs. At Alchemy Solar, we want to make sure that every homeowner receives the right battery for their needs and can take advantage of every incentive available.
If you are a homeowner interested in finding the right battery for your needs, contact Alchemy Solar for a free consultation to determine if the Tesla Powerwall 2 or LG Chem RESU 10H is the right fit for you.