Inaccurate SOC Readings Hurt Revenue

The Background

Energy storage system profitability depends on many factors, but two of the most important are availability and state-of-charge (SOC) accuracy. Unfortunately, this European-based operator was having problems with both. The operator’s trading strategy was based on SOC calculations taken from the BMS. However, these were wildly inaccurate, causing lost revenues, penalties, and warranty issues. ACCURE Battery Intelligence was brought in to understand the system better and identify the root cause.

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Solution and Approach

ACCURE ingested data from the system and incorporated data from similar systems around the world. A unique LFP state of charge estimation was applied to determine the differences between BMS and real SOC, and a correction was modeled.

Results and Benefits

An early SOC detection system was implemented to identify error build-ups, allowing the customer to recalibrate during low-value time slots. Continuous SOC calculations have minimized the errors to +/- 3%.  Previously, the SOC calculations were off by up to 50%.