Part Number: BQ40Z60
Hi all,
please could someone help answering/comment following points for customer:
1. Why does the parameter "True Rem Q" become negative when discharging the battery pack; the value reaches an average of -300 to -400mAh
- From which parameters does it depend that this value becomes negative?
2. Current calibration: We have calibrated the current at the “0-point” to 0 and -2A to -2A (Discharge) - in between the measured value is linear within the tolerance range
- Unfortunately, there is only one common calibration value for Charge and Discharge
- Charge mode but results in a different slope than in Discharge. As a result, although I can correctly measure the Discharge current, but the charge current is displayed by about 3% too high.(shunt resistance has no effect, balancing has been disabled for these investigations)
3. Current peak at the batch start
- The BQ40Z60 SYSPRESS function is used and the CHARGER_EN bit is permanently set
- First connect the battery pack to the device (SYSPRESS = active)
- Then apply a voltage at the input of the charger (for example 12V for batch of a 2s pack)
- Subsequently, the voltage at the input of the charger is interrupted for a short time
- After re-applying the input voltage, the charger will start fully and charge the battery for 1-2ms with approx. 6A (peak current depends on the input voltage)
- This triggers the error ASCCL
- Repeating this process, but before disconnects the battery pack for a short time from the device (SYSPRESS briefly inactive), this error does not occur
- Remedy: Set the CHARGER_EN bit to INACTIVE by default and only activate the CHARGER_EN bit by SW when the input voltage is clean at the charger input
4. Is there a document in which the internal calculations and correlations are well explained?
many thanks in advance.
Best regards,
Brian