Independent testing by TÜV Rheinland verifies Level 3 SOC performance for GoodWe’s ESA All-in-One energy storage, supporting more reliable charging, discharging and backup energy management.
Munich, Germany, 10/09/2026
GoodWe’s ESA Series, the residential All-in-One energy storage system, has achieved a Level 3 rating for State of Charge (SOC) performance following an assessment by TÜV Rheinland. Level 3 is the highest SOC estimation rating defined in the underlying 2 PfG 3165/12.25 test specifications, demonstrating the ESA Series capabilities to accurately estimate available battery energy. This estimation provides a reliable basis for charging, discharging, backup power management and overall energy management.
The ESA Series is an All-in-One residential energy storage solution that integrates a hybrid inverter, modular batteries and backup power switching into a single pre-wired, stackable system.
Accurate State of Charge with just 1.23 % deviation
State of Charge (SOC) indicates how much energy remains available in a battery system. Accurate estimation is critical, informing the system how to manage stored energy during charging, discharging and backup operation.
To assess SOC accuracy during ongoing operation, TÜV Rheinland subjected the ESA system to repeated charge and discharge cycles and compared reported SOC with a reference value established through testing. The maximum deviation was just 1.23%, meeting the requirements for Level 3.
Automatic SOC Recalibration and Battery Balancing
The assessment also evaluated ESA's ability to recover when the initial SOC estimate was inaccurate. A ten percent SOC deviation was deliberately introduced during testing to simulate an incorrect estimate of the battery's remaining energy. During subsequent operation, ESA automatically recalibrated its SOC estimate, correcting the initial deviation and restoring alignment with the reference SOC.
TÜV Rheinland also assessed how ESA manages battery clusters starting at different states of charge. In the balancing test, the initial SOC difference between two battery clusters was 39.6%. By adjusting the charging current allocated to each cluster, ESA progressively reduced the difference to zero under the specified test conditions.
A Reliable Basis for Residential Energy Management
Accurate SOC estimation, automatic recalibration and battery balancing provide ESA with more reliable information about the energy available across the battery system. This supports consistent control of self-consumption, backup reserves and overall energy use, while preventing inaccurate SOC information or imbalances between battery clusters from affecting system operation.
The Level 3 rating further strengthens the independently verified performance credentials of the ESA system. The series previously achieved Grade A, the highest rating under TÜV Rheinland's low-noise classification for residential energy storage systems.
About GoodWe
Established in 2010, GoodWe is a world-leading inverter manufacturer and smart energy solution provider. As of 2026, GoodWe has achieved an accumulative installation of over 100 GW in more than 100 countries. The company offers an extensive range of products and solutions for residential, commercial and industrial, and utility-scale sectors, delivering efficiency, safety, and long-term value. The manufacturer practices environmental and social responsibility throughout the lifetime of their products, constantly progressing and reporting on their ESG goals through annual Sustainability Reports and independent certifications. The company was awarded a Gold Medal by EcoVadis for its sustainability performance. GoodWe has around 6,000 employees worldwide, with over 1,000 dedicated to research and development. In 2025, GoodWe was named as a Global Tier 1 Power Inverter Manufacturer by BloombergNEF (BNEF) and Tier 1 PV Inverter Supplier by S&P Global. For more information, please visit https://emea.goodwe.com/.