Other Parts Discussed in Thread: BQSTUDIO, GPCRA0
Hi,
I am using a BQ40Z60 in a custom 4-cell Li-ion charger (4 x 3.7 V, 7800 mAh cells in series). We are using the EV2300 module and bq studio to set up the device. I am having issues setting up and calibrating the device.
I have carried out the following steps:
- Selected appropriate chemistry in bqStudio.
- Changed appropriate setting in the flash memory: use appropriate temperature for temperature detection, number of cells, voltage resolution etc. (see attached .gg file)
- Calibrated voltages for Cell 1, full batteries and AC adapter successfully.
- This is the first point where I believe there may be an issue. I am not sure as to where to carry out the current calibration from. Should this be applied to pin 1 when calibrating? I have not yet carried out the current calibration for this reason.
- Without calibration, we attempted to charge the batteries with the bq40z60 always choosing the pre-charging current as the charging current to use. This led to the overcurrent alarm flashing on and off and charging only available if we limit the current on the AC supply. The batteries stopped charging once the RSOC reached 100%, although the remaining and full charge capacities stated this was only 1800 mAh, 23% of the full charge capacity. Is this normal when you have not run the learning cycle at all, or would the chip not get closer to the actual theoretical value?
- I continued to run the learning cycle via the bqstudio software in manual mode. The discharge was at a through a 10 ohm resistor with a measured voltage across it of 14-16V giving 1400-1600 mA discharge through it. However bqstudio showed a current of approximately 2500 mA through each cell. Is this due to no current calibration or is it possibly something else?
- The learning cycle also ended after the relaxation period which is set to 6 hours in the software. Is it possible to run this manually (i.e. manually set the update status in flash memory to 04, discharge, relax, charge, relax etc) without using the built in learning cycle?
Please find attached the .gg files and a screenshot of the registers during relaxation of the discharged batteries.
Thanks in advance,
William