LG is one of the top names in home electronics and manufactures some of the most popular solar panels on the market. Along with offering high-quality solar panels, LG also offers one of the most popular batteries on the market: the LG Chem RESU 10H.
The LG Chem RESU (Residential Energy Storage Unit) 10H is a great battery option for homeowners. But determining if it is the right battery for you requires weighing its pros and cons.
Let’s take a look at the LG Chem RESU 10H pros and cons and help you determine if it is the best battery option for you.
How Does The LG Chem RESU Work?
The LG Chem RESU works like most batteries. It stores energy from a source, such as solar panels or a utility, and can provide that energy at a future time when needed.
With the rise in residential solar installations in recent years, LG Chem RESU batteries have often been paired with solar panels to store excess energy production. This provides a clean source of energy that can power the home both during the day and night, on cloudy days, as well as in the dark days of winter.
LG Chem RESU batteries can be used to offset Time-Of-Use (TOU) energy rates. Utility customers that are on a TOU pricing structure pay higher energy rates during peak usage times. To avoid these high energy costs, homeowners can install LG Chem RESU batteries to store solar energy during off-peak hours and use that energy when prices are highest.
This strategy can be especially useful for electric vehicle (EV) owners. That’s because most peak hours occur during the evening, when homeowners and children are returning from work and school. This is also the time when EV owners tend to plug in their electric vehicles. To avoid the high energy prices of charging EVs during peak hours, EV owners can pull from their battery to top up their EV instead of pulling power from the utility.
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LG Chem RESU Specifications
The LG Chem RESU has several qualities that set it apart from other top battery options and can help a homeowner choose if it’s right for them.
Let’s take a look at the basics of the LG Chem RESU: Power and Capacity, Compatibility, Chemistry, Performance. Warranty, and Cost.
Power & Capacity
In the US, the LG Chem RESU only comes in one size/model: the LG Chem RESU 10H. This model of LG Chem totes a maximum power rating of 5.0 kW and 9.3 kWh usable capacity.
To better understand these numbers, let’s break down the meaning of a battery’s maximum power rating and usable capacity.
A battery’s maximum power rating (measured in kilowatts, or kW) is the maximum amount of electricity that can be output at a single time. The higher the power rating, the better a battery can power more demanding appliances. Think of maximum power as a straw in a drink. The wider the straw, the more liquid can be sucked out at one time.
A battery’s usable capacity (measured in kilowatt hours, or kWh) is the maximum amount of electricity a battery can hold on a full charge. Usable capacity determines how long a battery can power the appliances it is supplying. Think of usable capacity as the drink the straw is pulling from. The larger the drink, the larger the usable capacity.
The balance between maximum power and usable capacity is important to consider. If the battery’s maximum power is high and can easily supply power-hungry appliances, it is important to ensure the energy capacity can sufficiently supply that power for the required time. Using the drink and straw analogy, it’s important to ensure the drink has enough liquid (energy capacity) so that the straw (maximum power) doesn’t deplete the drink too quickly.
When looking at batteries, it’s crucial to know how the battery will interface with other equipment, such as solar panels and solar inverters.
The LG Chem RESU is compatible with a wide range of brands (SolarEdge, SMA, Fronius, Huawei, etc.) and equipment (solar panels, solar inverters, including off-grid inverters). This sets it apart from batteries like the Tesla Powerwall, which can only be installed with Tesla solar panels, the Tesla Solar Roof, or Tesla inverters.
The LG Chem is also DC-coupled, which means it can receive power directly from the solar panels instead of going through an inverter first, which is necessary in AC-coupled systems. This provides greater efficiency by cutting out the need for DC-to-AC inversion. This also provides for a simpler integration with storage inverters.
The LG Chem RESU uses lithium-ion technology, specifically lithium nickel manganese cobalt oxide (NMC), to store energy. Lithium-ion technology has greatly improved in recent years, and it is now the preferred chemistry for batteries. This preference is due to lithium-ions’ many benefits, including high energy density, safer operation, lower maintenance, and greater depth of discharge (to be explained later).
Two key performance indicators are important when evaluating battery options: depth of discharge (DoD) and roundtrip efficiency.
Depth of Discharge (DoD): DoD indicates the percentage of a battery’s energy that can be discharged relative to the overall capacity of the battery without damaging the battery’s cells. For instance, if a battery with 10 kWh of usable capacity can be discharged to 1 kWh without damaging the battery, that battery has DoD of 90 percent. The higher the DoD, the better the battery will perform and the longer life it will likely have.
The LG Chem RESU 10H has a DoD of 95 percent, which is among the top performers in the battery market.
Roundtrip Efficiency: Roundtrip efficiency is a measure of electrical losses involved with charging and discharging a battery. The higher the roundtrip efficiency percentage, the more efficiently the battery can store the electricity it is receiving and then provide that electricity when needed.
The LG Chem RESU has a roundtrip efficiency of 94.5 percent, which means that for every 10 kWh of electricity put into the battery, 9.45 kWh can be output. This roundtrip efficiency is among the top in the battery market.
The LG Chem RESU comes with a 60 percent capacity, 10 year or 22.4 MWh energy throughput warranty. This means the LG Chem is guaranteed to produce at least 60 percent or its original capacity after 10 years or 22.4 MWh energy throughput, whichever comes first.
While this isn’t’ the strongest warranty offered by a battery manufacturer, it is still able to compete with other top brands.
See full LG Chem RESU 10H warranty here.
While cost isn’t the most important factor when buying a battery, it is definitely a huge influence.
Thankfully, battery costs have come down significantly in recent years, which has made batteries much more affordable.
The LG Chem RESU 10H costs between $5,000 to $7,000, which is about $750/kWh. However, this is before installation. Depending on the complexity of the installation and other factors, the cost of installation could reach $9,000 to $13,000 or more.
Luckily, a portion of this cost could be recouped through the federal solar tax credit (or Investment Tax Credit, ITC). The ITC can provide a 26% tax credit for the entire cost of a solar installation, including battery backup. Your solar provider can provide more details and ensure your system qualifies for the federal solar tax credit.
LG Chem RESU 10H Pros
As outlined above, there are many advantages the LG Chem RESU 10H has over its other competitors in the battery market. Here is a rundown of the largest pros of the LG Chem RESU 10H, including some not mentioned above.
- Lithium-ion NMC chemistry provides safer, more durable, more reliable battery than traditional battery chemistry
- Compatible with many brands and equipment types
- Does not require installation and equipment from particular company, unlike Tesla Powerwall
- Slim size compared to other batteries, such as sonnenCore
- DC-coupled setup provides greater efficiency and integration
- Impressive 95% Depth of Discharge (DoD)
- Strong roundtrip efficiency of 94.5 percent
LG Chem RESU 10H Cons
While the LG Chem RESU 10H has many impressive features, there are several disadvantages it has compared to other top battery competitors.
- 60 percent capacity, 10 year or 22.4 MWh energy throughput warranty falls short of both Tesla Powerwall and sonnen sonnenCore inverters
- Price comes in more expensive per Watt than Tesla Powerwall
- Battery recalls have tarnished the safety reputation of the brand (explained in the next section)
LG Chem RESU Battery Recall Warning
In 2020, LG Energy Solutions decided to recall and replace (free of charge) a range of RESU batteries with cells manufactured between March 2017 and September 2018 due to potential overheating and thermal runaway hazards.
The official announcement from LG Energy Solutions can be found here.
The affected ESS Home Batteries are equipped with cells from specific production lots manufactured between March 2017 and September 2018.
MODELS: RESU7H Type-R, RESU10, RESU10H Type-C, RESU10H Type-R, EM048063P3S4 and EM048126P3S7
You can check if your battery is affected by entering the serial number from the bottom or top identification label here.
Is The LG Chem RESU 10H RIght For You?
Determining whether the LG Chem RESU is right for you requires weighing many factors.
These factors can include why you want a battery. Do you want the battery for peace of mind during a power outage? Are you wishing to avoid TOU and high peak energy rates? Are you wishing to go off-grid?
It’s also important to factor in whether your utility offers net-metering, which will affect the financial viability of your battery investment.
The answer to each of these questions will certainly affect your decision. And unfortunately, these answers might not be easy to determine without the help of an expert.
Thankfully, Green Ridge Solar can help you decide if the LG Chem RESU 10H is right for you. We help Oregon homeowners install battery backup with and without solar panels, and we can answer any questions you might have about battery backup.
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