GoodWe’s residential all-in-one energy storage system, the ESA series, has achieved Level 3 for State of Charge (SOC) performance following an assessment by TÜV Rheinland against the 2 PfG 3165/12.25 test specification. Level 3 is the highest SOC estimation rating defined in the specification, demonstrating ESA’s ability to accurately estimate available battery energy and provide a reliable basis for charging, discharging, backup power management and overall energy management.
The GoodWe 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.
SOC indicates how much energy remains available in a battery system. Accurate estimation is critical because it informs how the system manages 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 its reported SOC with a reference value established through testing. The maximum deviation was just 1.23%, meeting the requirements for Level 3.
The assessment also evaluated ESA’s ability to recover when its initial SOC estimate was inaccurate. A 10% 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.
Together, accurate SOC estimation, automatic recalibration and battery balancing provide ESA with more reliable information about the energy available across the battery system. This supports more consistent control of self-consumption, backup reserves and overall energy use, while helping prevent inaccurate SOC information or imbalances between battery clusters from affecting subsequent system operation.
The Level 3 rating further strengthens ESA’s independently verified performance credentials, the series previously achieving Grade A, the highest rating under TÜV Rheinland’s low-noise classification for residential energy storage systems, underscoring GoodWe’s continued focus on both system performance and everyday user experience.
