The spread between the highest and lowest cell voltages in the pack exceeds the permitted threshold.
Common causes
Cells aging at different ratesBattery never reaching 100% SOC (balancing inhibited)One or more cells beginning to fail
What to check
STEP 1
Allow a full charge/discharge cycle to 100% SOC — passive balancing only operates at high SOC. In ShinePhone, ensure SOC target is set to 100% for this cycle
STEP 2
Monitor cell voltage spread over several cycles via ShinePhone. A spread that narrows after full cycles indicates balancing is working. A spread that continues to widen indicates a failing cell
Escalate if
Spread exceeds 500mV after multiple full charge cycles — cell failure, escalate for module replacement
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