LG RESU FLEX: High-voltage battery with Tetris system

The LG RESU FLEX has 2 main components: a control unit, the Battery Protection Unit (BPU), and at least 2 battery modules, the Battery Module Assemblies (BMA), with 4.3 kWh. The system can be expanded to up to 4 battery modules. Thus, it achieves a usable storage capacity of 17.2 kWh. If a larger storage capacity is required, 2 systems can also be connected in parallel. Combined, the high-voltage battery systems can offer a storage capacity of up to 34.4 kWh.

A BMA has a voltage of 132 V. If connected in series, 4 battery modules reach a voltage of 508 V. The LG RESU FLEX variants compared:

You can find more information about the product here.

LG Energy Solution will offer compatibility with 4 manufacturers of 3-phase hybrid inverters. The LG RESU FLEX can be integrated into one single system with the GoodWe ET plus, the Kostal Plenticore plus, the Fronius Symo Gen24 plus, and the SMA hybrid inverter. The 1-phase high-voltage hybrid inverter Primo Gen24 plus as well as the SMA Sunny Boy Storage 3.7-6 will also be compatible with the LG RESU FLEX after completion of the field tests and approval process.

The battery modules and the control unit have a depth of 14.8 cm. LG installs smaller JS1 battery cells and saves the DC/DC converter. In this way, the manufacturer creates a remarkably thin battery system.

You usually mount the high-voltage battery next to the hybrid or battery inverter in the basement or utility room. If the outside temperature is between at least -10 °C and a maximum of 50 °C, you can also install the battery system outside. At temperatures below -10 °C, the LG RESU FLEX switches off automatically. However, you should avoid direct sunlight. The optimal ambient temperature is between 20 °C and 30 °C.

You can mount the LG RESU FLEX either on the floor or on the wall. For floor mounting, you connect the battery modules behind the control unit. First, you attach a basic standing bracket to the control unit and to each battery module. Screw a bracket to the backmost battery unit and mount it on the wall with a small gap. Ensure that there is a safety distance of 30 cm next to and 50 cm above the LG RESU FLEX. Add the remaining battery modules one by one. Connect them to each other using the connecting cables from the terminal block in the middle. Pass the cables through the cable ducts provided along the sides of the module. At the end, put the control unit on.

With the optional floor mounting kit, the high-voltage battery system stands 13.8 cm above the ground and can withstand minor flooding. You need an extra mounting kit for each battery module and for the control unit. The kit also includes wheels so that the battery can be moved.

For wall mounting, you have 36 different geometric arrangement options. You can simply adapt the configuration according to the conditions on site. Refer to LG's quick installation manual to find out which configurations are possible. You need the corresponding wall-mounting kit for the installation. For this type of installation, one kit per battery module as well as one kit for the control unit is necessary.

In both the installation methods, you then connect the control unit to the inverter using a 6 mm² battery cable, a communication cable (CAN or RS485) and the Ethernet cable. Afterwards, you activate the LG RESU FLEX via the RESU-Monitor app for Android and iOS. Once connected, the app shows you the actual current flow status and the storage status of the LG RESU FLEX high-voltage battery system.

In order to install the LG RESU FLEX, you must first take LG's free certification training. The training takes place online, allowing you to participate from anywhere. You do not have to register beforehand. At the end of the training, you need to take an online test. If you pass, you can download your certificate from the LG website and become a certified installer for the LG RESU FLEX high-voltage battery. Moreover, the certificate gives the product a full product warranty.

The new LG RESU FLEX high-voltage battery system is a new addition to the RESU Prime high-voltage battery. For the first time, LG offers you a home system for 3-phase hybrid inverters. Multiple mounting options make the system extremely flexible. LG is also working intensively to increase the number of compatibilities so that the new battery system also works with Fronius. Combination with SolarEdge is not possible.

• The LG RESU FLEX comes in 3 storage capacities and is the manufacturer's first home system for 3-phase hybrid inverters.
• Two mounting options as well as the Tetris principle for wall mounting offers more flexibility.
• The high-voltage battery is compatible with many manufacturers, including Fronius.