LG is a leader in the home electronics industry and manufactures some of the most popular panels featured in quotes to shoppers on the EnergySage Solar Marketplace. Outside of making some of the highest quality solar panels on the market, LG’s battery subsidiary, LG Chem, produces one of the most popular batteries in the U.S. market: the LG Chem RESU 10H battery.
How does the LG Chem RESU work?
The LG Chem RESU pairs well with solar panel systems, especially if your utility has reduced or removed net metering, time-of-use rates, or demand charges. Installing a storage solution like the LG Chem RESU with a solar energy system allows you to maintain a sustained power supply during the day or night, as long as you store enough power from your panels when the sun is shining.
As with many other home battery products, the LG Chem RESU is sized for day-to-day use at your home and is often paired with a home solar panel system. When your solar panels produce more electricity than you can use in your home, you can store the excess electricity in the battery system instead of sending it back into the grid. Later, when your panels aren’t producing enough electricity to meet your home’s needs, you can use the electricity stored in your battery instead of having to buy it from your utility company.
Key things to know about the LG Chem RESU
LG Chem highlights the RESU’s compact size, ease of installation, and safety as some of their top selling points. As a dedicated chemicals company, LG Chem has the history and knowledge to back up their claims of quality and safety for their battery products. And as one of the most popular residential batteries on the market, it seems that consumers agree.
When evaluating the RESU, there are various important metrics and technical specifications to keep in mind. Among the most important are the size of the battery (power and capacity), its chemistry, depth of discharge, and roundtrip efficiency.
The LG Chem RESU comes in only one model/size in the United States: the LG Chem RESU 10H. Two important metrics to keep in mind when comparing the RESU 10H to other home storage options are power and usable capacity. 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 from your battery on a full charge. The LG Chem RESU 10H boasts a maximum power rating of 5.0 kW to go along with 9.3 kWh of usable capacity. The RESU system is also, to an extent, modular, meaning you can add multiple battery products to your storage setup. For example, you might want to install multiple RESU batteries for a home with high energy demands. However, LG Chem recommends no more than 2 RESU batteries wired together in parallel.
Think of your battery like water running through a pipe. Energy capacity is the amount of water available to push through the pipe, while power is the size of the pipe itself. Larger pipes allow more water to flow through at once, which depletes the water faster. Similarly, a battery with a high power rating can deliver more electricity at one time, but will burn through its available energy capacity faster too.
A battery’s power determines what appliances you can run with it at once, while usable capacity determines how long those appliances can be run. Batteries with a higher power rating are capable of powering more robust appliances or many appliances at once, while batteries with a higher usable capacity can store more total energy and thus can run your appliances for longer periods of time without needing to recharge.
The functionality of one solar battery next to another can vary; some batteries have excellent off-grid capabilities, while others offer software solutions for rate arbitrage. Here the important qualities of the LG Chem RESU:
LG Chem has made a concerted effort to ensure their battery solution is compatible with most common brands and types of off-grid and hybrid inverters. This means that, as long as your installer installs the correct components, your LG Chem battery will be able to provide backup power for your home when the grid goes down.
The LG Chem RESU is a lithium-ion storage product; specifically, it is a lithium nickel manganese cobalt oxide (NMC) battery. This is one of the most common lithium-ion battery technologies, and for good reason: relative to other types of batteries, NMC batteries are known for their high energy density (the amount of energy they can store relative to the physical space they take up) and increased safety. To learn more about how different lithium-ion battery chemistries stack up against one another, check out our overview of battery chemistry differences.
Two key ways to evaluate the performance of a solar battery are its depth of discharge and roundtrip efficiency.
Depth of discharge (DoD) indicates the percentage of a battery’s energy that has been discharged relative to the overall capacity of the battery. Because the useful life of a battery decreases each time you charge, discharge, and re-charge it, many battery manufacturers specify a maximum DoD level for optimal battery performance. In general, batteries with a higher depth of discharge are considered better quality products. The LG Chem RESU boasts a depth of discharge of 95 percent across all battery sizes, reflective of its safe and advanced NMC battery chemistry.
Roundtrip efficiency is a measure of electrical losses involved with charging and discharging a battery. The higher the efficiency percentage, the more efficiently the battery is able to convert incoming electricity into stored electricity and then back into usable electricity. The LG Chem RESU line has a high roundtrip efficiency of 94.5 percent; this means that for every 10 kilowatt-hours (kWh) of electricity you put into the battery, you’ll receive 9.45 kWh of output.
LG Chem RESU warranty coverage
- Warranty period: 10 years or 22.4 MWh energy throughput
- Guaranteed end of warranty capacity: 60%
- Throughput warranty: 22.4 megawatt-hours (MWh)
In most cases, homes with an RESU battery will charge and drain the battery every day. The RESU comes with a 10-year warranty. LG Chem guarantees that the battery will maintain at least 60 percent of its capacity to hold a charge during that time period. LG Chem also offers an energy throughput warranty – the 60 percent retained capacity after 10 years is only valid if the total energy throughput over the 10 year period is less than 22.4 megawatt-hours (MWh). Summed up, your LG Chem RESU battery is warrantied to retain at least 60 percent of its capacity by the time you hit a lifetime of 10 years or an energy throughput of 22.4 MWh, whichever happens first.
LG Chem’s battery technology is similar to other rechargeable batteries both large and small: as time goes on, the battery loses some of its ability to hold a charge. Think of how the battery life of a brand-new smartphone compares to one that is a few years old. As you continually charge and drain your phone’s battery, it starts to lose some of its ability to hold a charge.
The battery life of your RESU battery will deteriorate in the same way. That isn’t an indicator of a product flaw – all batteries lose some of their ability to hold a charge over time, whether it’s an electric vehicle battery, a home energy battery, or a rechargeable AA battery. This is why LG Chem offers a warranty that guarantees a certain amount of storage capacity.
If you want to compare individual battery models side-by-side, our battery Buyer’s Guide lets you select products and compare them based on efficiency, capacity, power, and more.
How much does the LG Chem RESU cost?
A solar battery installation isn’t a simple as a list price for a component – depending on your electrical setup, among other factors, installation costs can vary widely. As a rough estimate, you can expect the LG Chem RESU 10H to cost between $9,500 and $13,000 with a full system installation. That number includes the battery itself, an inverter, various other equipment costs, and estimated installation costs.
If you want to install the RESU as part of a solar-plus-storage system, battery costs are just one part of the equation. A 5 kilowatt (kW) solar energy system costs anywhere from $9,000 to $15,000 depending on where you live and the type of equipment you choose.
That may sound like a lot of money, but installing a solar-plus-storage system can be a worthwhile investment. Whether or not the LG Chem RESU makes sense for you is determined by the way that your electric utility structures its rates, as well as your reasons for installing a solar battery.
In some cases, depending on where you live, you may have access to financial incentives that can reduce your home energy storage installation costs. For instance, if you live in California, you could get a cash rebate that covers most of your home battery costs through the Self-Generation Incentive Program (SGIP). Other states (such as Massachusetts) are in the early stages of evaluating battery storage performance incentives as well, and several states already provide cash rebates.
Where to buy the LG Chem RESU
The LG Chem RESU10H battery is currently available through the company’s installer network in the U.S. Whether you want to install an LG Chem RESU or other home battery pack, you will most likely need to work through a certified installer. Adding energy storage technology to your home is a complicated process that requires electrical expertise, certifications, and knowledge of the best practices required to install a solar-plus-storage system correctly.
A qualified EnergySage-approved company can give you the best recommendation about the LG Chem home battery system and other energy storage options available to homeowners today. 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.