LG Chem RESU Solar Battery Review

The LG RESU Battery Range

The RESU or ‘Residential Energy Storage Unit‘ range consists of both 48 volt and higher voltage 400 volt lithium-ion battery options. The 48V (LV) series is available in 3.3kWh, 6.5kWh, 9.8kWh and 13kWh. While the higher voltage (HV) 400V batteries are available two sizes – 6.5kWh and 9.8kWh. A new Gen3 16kWh high-voltage battery is due to be released late 2020, see full details below.

All size figures are based on the total available capacity (kWh), however usable capacity is limited to 90% for the 48V version, and 95% for the 400V series. For larger residential systems a maximum size of 19.6kWh can be achieved by linking two of the 9.8kWh (RESU10) battery units together using the LG RESU plus battery combiner unit – the RESU plus.

The larger capacity RESU13, 48V battery was released in 2018 in order to compete with the Tesla Powerwall 2 (13.5kWh) battery.

All LG Chem RESU batteries are IP55 weather-rated. This means they can be installed in a semi-outdoor location such as a verandah or carport, but should not be located in a position exposed to direct sunlight, especially during the warmer months. As with any electrical/battery system, excessive prolonged heat is detrimental to the performance and life of the system.

Download the detailed LG chem specification data sheet here

High Voltage Battery options (400V)

Since the release of the first Tesla Powerwall, there has been an emerging trend towards higher voltage 300 – 400 Volt battery systems. These have several benefits over the traditional ELV 48V batteries including, increased efficiency, lower cable losses and the ability to be DC coupled with the solar array which operates at a similar voltage. However, all dedicated off-grid battery inverters operate within the traditional 48V range so the higher voltage batteries will generally not work for off-grid installations.

There is a growing number of compatible high voltage hybrid inverters including the well regarded SolarEdge StorEdge hybrid inverter, the new Huawei FusionHome and the SMA sunny boy storage which is now available in higher capacity (up to 6.0kW output).

The new – LG Gen3 RESU 16H

LG have announced their third-generation (Gen3) battery system, the RESU 16H due to be released in October 2020. Over the last two years demand has grown rapidly for larger, more powerful battery systems which can compliment the movement towards all-electric-homes and electric vehicle charging. One area where the current range of LG batteries are limited is maximum power output which is fixed at 5kW continuous and 7kW peak (RESU10), even with two batteries combined.

The Gen3 RESU battery from LG Chem addressed these limitations with a much greater 16kWh storage capacity and higher continuous power rating of 7kW. However, the most significant boost is in regards to peak power which has increased to an impressive 11kW. The larger peak power rating means the backup loads on a typical household can now include high-surge power appliances like pumps and air-conditioners (so long as the inverter can also deliver the power required during an outage!)

The new Gen3 RESU 16H battery is the largest and most powerful residential battery from LG chem.

More power = more weight

Developing a larger capacity battery is easy in theory as the manufacturer just needs to add more cells making the battery bigger and heavier. However, the size and weight of high capacity batteries above 10kWh really becomes problematic in regards to handling and installation. Thankfully, this is one area where LG has taken on board feedback from installers and created a modular battery system which can be carried and handled by two people.

Wide Range Of Compatible Inverters

LG Chem has been listening to solar installers and working with many inverter manufacturers to ensure their product is compatible and easily configured with almost all of the best and most popular hybrid and off-grid battery inverter/chargers on the market. Unlike the first Tesla Powerwall, which was limited to two inverter types, the range of compatible inverter brands for the RESU range (LV) now includes a vast range of 48V hybrid and off-grid inverters.

All-in-one Hybrid Inverters – 48V

• SolaX Power hybrid

• Sungrow hybrid

• Goodwe SE

Off-grid / Hybrid Inverters – 48V

• Victron Energy

• SMA Sunny Island

Hybrid Inverters – HV 400V

• SolarEdge Storedge

• SMA SBS-2.5 and SBS-5.0

• Huawei SUN2000L

• Fronius Symo

More options coming – LG chem are also working closely with several leading inverter manufacturers including SMA, Fronius and SolarEdge and will be delivering an even greater range of battery options throughout 2020.

Safe Laminated Lithium Polymer Cells

As opposed to many other manufacturers which use cyclindrical battery cells LG chem use a unique Polymer ‘pouch’ flat laminated battery design (PH3) which LG claim enables much higher energy density with increased reliability and safety. Layering the battery cell sections rather than rolling or bending the cell structure reduces the likely hood of failure and enables even heat dissipation across the cell area.

Fire Safe – The LG chem lithium modules have been fire tested to the UL1973 test standard which requires there to be no explosion or sign of fire when the battery cells is forced into a thermal runaway condition.

LG Chem Warranty

The LG chem RESU warranty is 10 years which is based on 2 main factors, the remaining capacity and energy throughput based on charge and discharge cycles. All batteries reduce capacity over time due to internal cell degradation, the LG chem warranty ensures the retained storage capacity is greater than 60% of the original amount. The warranty states that…

“LGC warrants and represents that the Product retains at least 60% of Nominal Energy for the either 10 years after the date of the initial installation or for a minimum Energy Throughput as per the table below (whichever comes first) when the battery system is operated under a normal use followed by the specification and the manual provided by LGC”

See the full LG chem warranty document here

Careful in hot climates

The warranty also contains detailed operating criteria which limits the operating temperature and energy throughput over the battery life. This can be problematic for installations in hotter climates such as regional Australian towns and remote locations. Since exposed outdoor installation can easily reach 45 degC during the afternoon in many Australian towns, careful consideration needs taken when locating the battery. Preferably locations include inside a garage or a well insulated/ventilated area as high ambient temperatures above 45 degC can accelerate battery aging and reduce storage capacity.

The LG RESU batteries have built-in sensors to monitor cell temperature and voltage to help extend battery life. To reduce degradation or the chance of thermal runaway the LG battery management system de-rates the power output by 50% once the internal cell temperature rises above 50 degC and further de-rates power output completely once the temperature goes above 55 degC.

Battery Cost Comparison chart

Solar battery comparison – LG Chem RESU V’s Tesla Powerwall 2 plus leading batteries from the top manufacturers. See the complete solar battery comparison and review here for full details and specifications including estimated lifetime, cost per KWh, power output and compatibility with leading inverters.

Summary – Wrap Up

LG chem RESU is one of the best battery systems on the market with an extremely good reputation for quality and affordability. The RESU’s success is based on several factors, including the unique cell design, safety, performance, and service backed by a huge multi-national company.

The only concern is in regards to systems installed in high-temperature environments or exposed locations. Prolonged high temperatures above 40 degC or direct sunlight could result in reduced performance or even system shutdown to prevent overheating. Another issue is the battery will automatically shut down after a short amount of time if communication is lost with the inverter. However, this is only problematic with off-grid systems.

LG Chem stands out from the crowd of lithium battery manufacturers due to high build quality, value for money, diverse range of batteries, and compatibility with most leading inverters on the market. On the service side, the high level of industry interaction, training and support, has helped improve reliability and ensured the RESU systems are installed correctly.

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