Tool/software:
Hello !!
Apologies that our first exchange has to be about a technical issue, but we are currently facing a problem with the BMS on our 10S4P and 10S3P battery packs, which we use in our micromobility kits.
We are experiencing unexpected battery shutdowns while the bikes are in use, even though the displayed State of Charge (SOC) is above 0%.
Upon analyzing the discharge curves (as illustrated in the graph below), we noticed a significant voltage drift between the cells. Typically, one cell—often cell C0—drops faster than the others, triggering a shutdown due to Cell Under Voltage (CUV). This penalizes the remaining cells and reduces the overall capacity (SOC), and consequently the State of Health (SOH), which is the basis for the REALCapacity.
We would appreciate your support in helping us clarify the following points:
- What could be causing this imbalance during discharge?
Here are the charging parameters we are currently using:
- Charger voltage: 41.7 V / 4 A
- Cell Balance Threshold: 3800 mV
- Cell Balance Window: 50 mV
- Cell Balance Min: 10 mV
- Cell Balance Interval: 1
Here are the charging parameters we are currently using:
- Charger voltage: 41.7 V / 4 A
- Cell Balance Threshold: 4100 mV
- Cell Balance Window: 0 mV
- Cell Balance Min: 10 mV
- Cell Balance Interval: 0 s
Which parameters should we adjust to improve the accuracy of SOC and SOH estimations, so that charge and discharge corrections better reflect the actual values?
What discharge profile (current vs. cell state) would you recommend?
