Flexibility & aesthetics combined: What are the advantages of the new RESU FLEX high-voltage storage system from LG Energy Solution?

With its new RESU FLEX high-voltage system, LG Energy Solution has developed a product that offers the ideal level of flexibility in terms of expandability and installation to meet the needs of its customers, and thus representing a true standout from conventional energy storage systems on the market.

In response to the continuing increase in demand for solar energy in the residential sector, three attributes in particular are in demand after availability: expandability, freedom in the form of installation and, increasingly, the aesthetics of the products. RESU FLEX is LG Energy Solution’s first home storage system for 3-phase hybrid inverters to hit the market.

RESU FLEX in Figures

The new storage system consists of two main components, a control unit (BPU; Battery Protection Unit) and at least two battery modules (BMA; Battery Module Assembly). Each battery module has a capacity of 4.3 kWh and can be operated according to the user’s needs by expanding from 2 to 4 battery modules in different expansion stages. In its full expansion stage, a RESU FLEX system has a usable storage capacity of 17.2 kWh. In addition, two systems can be paired and operated in series to achieve a capacity of 34.4 kWh. In this application, one of the control units takes over the control of all modules as “master”, the second control unit serves as “slave”. In the full-scale version of a RESU FLEX system, 4 battery modules are connected in series to reach a voltage of 384 – 531,2 V. From our point of view, a system expansion makes sense within the first three years of use.

The Models at a Glance

For more details, please read out leaflet here.
RESU FLEX floor assembly in extension with a usable energy storage capacity of 8.6kWh
RESU FLEX wall mounting in extension with a usable energy storage capacity of 8.6kWh
RESU FLEX accessory kit for floor mounting
RESU FLEX accessory kit for wall mounting

Product Development up to Date

One of the key product features is the shallow depth of the battery modules and control unit. The depth of 14.8 cm per module allows a particularly flat installation in utility rooms, basements and garages, which otherwise offer little space for installation. For these requirements, LG Energy Solution developed smaller JS1 battery cells based on NMC, which have a high energy density and has been tested under the UL9540A.

LG Energy Solution’s JS1 Cell

Uncomplicated Monitoring through App Interface

The RESU Monitor app is a registration and monitoring application that allows installers and system owners to monitor the condition of the system, perform system-relevant updates and manage warranty-related information. Each home storage system is connected and registered with the RESU Monitor app during installation and commissioning. These details are part of the warranty policy with which system owners can secure a warranty period of up to 10 years. In addition to monitoring the system status, the communication status of the battery can be called up and there is an interface for regular updates and the manufacturer’s technical support.

RESU Monitor App

Compatible Inverters for RESU FLEX

The owners can choose from four manufacturers of 1-phase and 3-phase hybrid inverters to operate the high-voltage storage system from LG Energy Solution. As laboratory tests have been carried out, the system can already be integrated with the Kostal Plenticore plus, the Fronius Symo GEN24, and GoodWe ET plus. At a later date, RESU FLEX should also be compatible with SMA’s new 3-phase hybrid inverter, Sunny Tripower Smart Energy. 1-phase high-voltage hydrid inverters such as the Primo GEN24 plus and the Sunny Boy Storage 3.7-6.0 from SMA is also suitable to use with with RESU FLEX.


  • Modular home storage for 3-phase & 1-phase hybrid inverters
  • Available in storage capacities of 8.6 kWh, 12.9 kWh, 17.2 kWh
  • Expandable from 1 control unit (BPU) and 2 battery modules (BMA) to up to 4 BMA per system
  • Compatible with Kostal, Fronius, SMA, GoodWe
  • Floor and wall mounting possible

The First RESU FLEX Installation in Europe:

At the end of July, LG Energy Solution has completed the very first installation of RESU FLEX system in Europe, at the own house of a popular YouTube tech reviewer DieserDad. DieserDad is one of Germany’s favorite YouTubers for energy transition and electric mobility topics, and is widely known for his product review videos that are both informative and entertaining.  

DieserDad in August has uploaded a video footage of his own personal experience of installing RESU FLEX at home, drawing extensive online attention among home battery enthusiasts in Germany and other parts of Europe. His first video has garnered more than 120,000 views in the first few days of posting, and he plans to upload one more video on initial experience of using RESU FLEX system and another one on long-term user experience over the upcoming months.

To check out the unique footage of RESU FLEX installation at DieserDad’s YouTube Channel:

Certification Training

We are excited to offer our installation partners an online RESU FLEX certificate training course to learn more about our new product. To become a certified installer of RESU FLEX, please visit the link to our RESU Academy below, as the certificate is a prerequisite for the product warranty.

The RESU FLEX training and certification test are now available here.

The registration in the Partner Program can be done here.

All product specific documents are available for download here.

Do you have questions about the product? We are happy to help!

Lukas Lambert, Marketing Manager +49 (0) 173 5499 034 /


Recent Posts


Lukas Lambert

Lukas Lambert

is Marketing Manager at LG Energy Solution and is responsible for the European-wide marketing activities of the RESU product line in the residential storage segment as well as the Premium Installer Program.

Close Menu

Change language

Stay in touch?

Sign up for our free Newsletter and receive news and technical updates from the world of storage systems first hand!



Nichts mehr verpassen?

Melden Sie sich für unseren kostenlosen Newsletter an und erhalten Sie Neuigkeiten und technische Updates aus Welt der Stromspeicher aus erster Hand!