Other Parts Discussed in Thread: BQSTUDIO, GPCCEDV
Tool/software:
Hello,
We have encountered a strange phenomenon while using the BQ4050.
**Background:**
The BQ4050 is used to manage a 4-series lithium battery pack with a designed capacity of 6600mAh, and the initial FCC (Full Charge Capacity) value is also set to 6600mAh. Approximately 20K units of the product have been shipped.
**Issue:**
Recently, a customer reported that the remaining capacity (RM) when the battery pack is fully charged (100%) is very low, only a few hundred mAh. The customer believes that the capacity has significantly degraded and requested a return for repair. The customer has used the product for 11 months.
**Testing:**
After returning the product to us, testing revealed that the battery cells are in good condition, and the pack can still deliver a capacity of 6300mAh when fully charged. However, the FCC measurement by the BQ4050 was incorrect. We conducted charge-discharge cycles, and each cycle increased the FCC by 512mAh (consistent with the datasheet). After 10 cycles, the FCC has returned to normal.
**Inquiry:**
What could have caused the FCC to drop below 1000mAh? How should we address the customer's complaint?
**Note:**
Out of the 20K units shipped, only this customer has reported this issue.
Could you please help with the issue?
Thnaks very much.