2023 SunPower Solar Review Guide (Costs, Quality, & More)
By Kristina Zagame /
In this EcoWatch guide on LG solar batteries, you’ll learn:
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Tech giant LG entered the home energy storage business in 2018, leveraging its six decades of experience in electronics to develop some of the best batteries of recent years.1 This LG solar battery review will cover one of the most popular series available on the market today — the LG Residential Energy Storage Unit (RESU).
We should note that LG recently decided to exit the solar modules business. Here’s what it had to say about its other energy products: “The company will concentrate on growth sectors and plug into a new era of sustainability through rapidly evolving products and solutions including Energy Storage Systems (ESS), energy management solutions and other yet-to-be-announced advancements.”2
The new battery subsidiary of LG Chem has been rebranded as LG Energy Solution.
One of the most valuable inventions of modern times, batteries are chemical devices that can store energy and supply it at a later point in time. This makes them particularly suitable for pairing with intermittent renewable energy sources like wind and solar power.
Solar batteries, such as the LG RESU, store excess energy generated during the day for use at a later time. This could be at night or during peak times when grid electricity is at its most expensive. They are a great solution to tackle power outages or to create a fully off-grid solar system.
LG batteries store the energy coming from the solar panels as direct current (DC) power. When it comes time to use that energy, your battery channels it to an inverter that converts it into usable, alternating current (AC) power. AC power is what we use to run electrical loads in our homes.
A battery is specified by its total energy capacity, measured in kilowatt-hours (kWh) or watt-hours (Wh). It reflects the number of kW it can supply over a certain amount of time. For example, LG’s 16 kWh battery can theoretically supply 2 kW of power for eight straight hours.
Today, there are several types of batteries, with lead-acid and lithium-ion being the most common. The RESU series by LG Energy Solutions uses lithium-ion batteries with nickel-manganese-cobalt (NMC) cells.
Lithium batteries are known to be safer, more efficient and longer-lasting than the traditional lead-acid units. More importantly, li-ion batteries also have a better energy density, meaning they can pack more capacity in a smaller space.
Depending on the model, LG’s RESU models can store 9.6 to 16 kWh of solar energy.
Until last year, the LG RESU was available in just one size — the LG Chem RESU 10H (10H indicating 9.8 kWh of capacity). In 2021, LG launched its third generation of batteries, dubbed the RESU Prime, consisting of two models — the 10H with 9.6 kWh capacity, and the 16H with a massive 16 kWh of usable energy.
The older RESU 10H comes in two different versions — 10H-C and 10H-R. The main difference between the models is that each is compatible with different brands of inverters.
The newer Prime models, on the other hand, come in single versions compatible with most major solar inverter brands, such as SMA and SolarEdge.
The RESU 10H and RESU 10H Prime have a continuous power rating of 5 kW and a maximum power rating of 7 kW. The RESU 16H Prime goes even further and has a 7 kW continuous output and can supply up to 11 kW of peak power for 10 seconds.
LG’s RESU models are scalable, meaning you can connect them together to create a larger energy storage system. For example, by connecting two 16H Prime batteries, you can create an enormous 32 kWh battery bank.
Aside from the above high-voltage models, LG offered a 6.5 kWh model known as the RESU 6.5, which was a smaller, 48V output version of the RESU 10. The RESU 6.5 is now discontinued.
All of the RESU models are DC-coupled, meaning they operate on the DC side of the circuit (before the inverter). This limits their functionality but makes them more efficient than AC-coupled batteries.
Here’s a table that gives an overview of all RESU models:
|Model||LG RESU10H-R||LG RESU10H-C||LG RESU 10H Prime||LG RESU 16H Prime|
|Total energy capacity (kWh)||9.8 kWh||9.8 kWh||9.6 kWh||16 kWh|
|Power rating (continuous)||5.0 kW||5.0 kW||5.0 kW||7.0 kW|
|Power rating (peak)||7.0 kW||7.0 kW||7.0 kW||11.0 kW|
|Voltage range (V)||350-450 V||350-450 V||350-450 V||350-450 V|
|Dimensions (W x H x D, inches)||29.3 x 35.7 x 8.1||29.3 x 35.7 x 8.1||19.8 x 32.2 x 11.6||19.8 x 42.8 x 11.6|
|Approximate weight (lbs)||214 lbs||220 lbs||244 lbs||350 lbs|
|Warranty||60% capacity after 10 years||60% capacity after 10 years||70% capacity after 10 years||70% capacity after 10 years|
Before we get into costs, it’s worth clarifying that the prices of solar battery installations vary; solar installers purchase batteries wholesale, so the costs that consumers see are set by the installer and based on the installer’s location, size and experience.
That being said, market research shows that LG’s 10H models typically cost around $7,000 and can go up to $9,000 including the installation cost. The larger, 16 kWh model can cost around $10,000 or more, going up to $13,000 with installation.
To put this into perspective, LG’s batteries cost around $700-900 per kWh of storage capacity. These are not the most attractive prices, given that some newer brands offer batteries for less than $500 per kWh.
However, LG’s solid reputation for quality and reliability justifies the upfront cost of its batteries for many homeowners.
The pricing of LG’s batteries is comparable to the Tesla Powerwall, its greatest competitor and one of the most popular home solar batteries in the U.S. The Powerwall offers a higher storage capacity of 13.5 kWh and costs upwards of $12,000 including installation.
Modern solar batteries, including LG’s li-ion batteries, are expected to last a decade. As such, the industry standard among solar battery manufacturers like LG is to offer a 10-year warranty.
Although LG’s warranties cover all the RESU models for 10 years, there are a few subtle differences between the warranties of the older and newer models.
The warranty of the older RESU 10H battery guarantees at least 60% of the rated capacity after 10 years. Both the RESU Prime models have improved long-term performance, and warranties that guarantee a minimum of 70% of rated capacity at the end of 10 years.
In rare cases, someone who charges and discharges the batteries frequently may end with a capacity lower than 70% (or 60% for the older RESU) after 10 years. In this case, LG specifies that if the battery has been used for a total consumption of 22.4 MWh, this will override the 70% (or 60%) value.
If you divide 22.4 MWh by 3,650 (10 years), you get about 6.13 kWh of available capacity per day, which is more than sufficient for most homes.
There are dozens of battery storage systems available in the U.S., but the top few offerings come with similar specifications — and they rule the market.
These include LG’s RESU models, along with offerings from Tesla, Generac, Enphase and Sonnen to name a few. Take a look at three of the highest-rated batteries in the market:
|LG RESU||Tesla Powerwall II||Generac PWRcell|
|Capacity||9.6 – 16 kWh||13.5 kWh||9 – 18 kWh|
|Price||$7000 – $13000||$12,750||$9,999 and above|
|Warranty||10 years||10 years||10 years|
|Battery Chemistry||Li-ion (NMC)||Li-ion (NMC)||Li-ion (NMC)|
|Depth of Discharge (DoD)||95%||100%||84%|
Unlike solar panels, energy storage systems are not primarily used as a means to lower your electricity bill. While battery packs can do that (for example, if you draw power from them during time-of-use peak pricing), it is still not a significant bill-saving measure. Rather, most readers are interested in LG batteries to provide whole home backup power during blackouts or other incidents.
As such, we recommend LG home batteries to our readers who are looking to prioritize reliability. The company has a reputation for being extremely reliable and has rock-solid financial stability. Its batteries won’t be the cheapest, but the added cost may be worth the peace of mind that your manufacturer will be around to provide support and honor your warranty for decades to come.
A more minor advantage (but equally important to some readers) is the compactness of LG’s batteries. While the battery cells of previous generations were heavier, its newer versions are more compact and lightweight.
The company even claims that two people can carry and assemble the unit, which is extraordinary for a battery of this capacity.
Overall, LG batteries are an excellent choice for anyone who wants a sleek, compact backup power unit with state-of-the-art battery chemistry, easy installation and a trustworthy brand to honor the warranties.
While companies like Tesla or Enphase may be able to provide products with a lower price tag or flashier capabilities, neither company can match the experience and reliability you enjoy with LG products.
Here’s a quick look at the basics of the LG RESU Prime:
Below are some of the most commonly asked questions about LG’s solar battery backup products.
LG provides an industry-standard warranty of 10 years with its batteries. This is the minimum duration the batteries will last. Ideally, the batteries should last at least five years after that — but their energy storage capacity will begin to suffer after ten.
While there is no single manufacturer that can be awarded the title of the best battery brand, LG has positioned itself as one of the leaders in solar battery technology. It even supplies batteries to a number of electric vehicles worldwide.
LG, Enphase, Tesla, Generac and Panasonic are currently regarded as the most popular and reliable battery manufacturers in the market.
What makes a battery worth buying can be subjective, but in most cases, the factors that make a battery the right choice are good round-trip efficiency, a reliable brand, proven customer service and an affordable price tag. LG’s batteries may not be the cheapest on the market, but they are worth it if you value reliability, efficiency and customer satisfaction.
LG Energy Solution spun off from LG Chem. It manufactures battery systems for a variety of uses, including electric vehicles, solar systems, drones, ships and more.