Part Number:BQ40Z60
I have custom charger design, based on BQ40Z60 evaluation board, with changes:
- without all U1 protection circuit
- without precharge circuit: F1, Q7, C10, R18, R22
- AFEFUSE pin tied to GND
- R14 changed to 1K (we have high voltage drop on ACP pin after charge was enabled)
- C18, C20, C24, C25, C27 changed to 4,7uF/25V
- no Q10-Q13 led circuit
- voltage divider: R21 = 330k, sum of R26-R29 = 24k
- BQ40Z60 firmware: bq40z60_v0_15_build_21
- connected cells: 4x parallel NCR18650GA-Panasonic with thermistor and cables for balancer
We have problem witch charging currents mismatch. BQ studio is reporting charging current to 1794mA, but for cell1-4 show about 1940mA. But to the cells is going about 2300mA (we connected 0.01R to +V4 cell, and measure voltage drop).
All voltages are calibrated and reported properly.
When I want to calibrate current (using that add-on 0.01Rfor metering), CC Gain, and Capacity Gain drops to 4.324. And all reported currents got messed up.
But sometimes I have "good" board, charging current 1794mA is almost the same as cell1-4 currents, but physically it delivers to battery about 2000mA. It works on the same golden image as other boards, only voltage calibration was done before metering.
How to fix that?
(Please visit the site to view this file)
