BQ3050 Behaviour&Settings

Christophe, 

The symptoms sound like FCC is not updating though the course of your charging and discharging. Do you charge the pack until charge complete and then discharge it down below 7% charge? This is the requirement to update FCC. The gg file looks like the golden file. Can you provide the one from one of the defective packs? A log file for a charge / discharge cycle would also be helpful.

Thanks

Tom

Thomas,

I'm out of the office until Monday but I will give you a log of charge / discharge cycle as soon as possible.

Considering the gg file, I changed:

• three cells configuration to four cells configuration
• update the various pack voltage threshold for four cells
• change the 4400 mAh value to 3700 mAh value in the whole file.

I stop discharging my pack at 7% or just below. Maybe I should change my threshold to discharge the pack a bit more. 

By the way, I've limited the full charge value to 16V (4V per cell) and not 16.8V (4.2V per cell) in order to increase the battery life expectancy. Do you think this is correct ? 

Thank you for your help,

Regards,

Chris.

The lower charging voltage should be okay as the Taper Current is reached and the FC bit is set indicating that the pack is fully charged. Try discharging down to 5%, or lower, to make sure that the gauge has fulfilled the conditions to update FCC.

Thomas,

Please find in attachment the log files for two battery pack. Foreach pack, there is a log for the charge (6 - 100%) and the discharge (100% - 6%). I'm currently recording a discharge from 100% to 4% to test your discharge condition. 

By the way, at the end of the charging cycle, the Tapper Current is reached and the FC bit is set, so it's seems quite logical so far. My question is, why some charger design maintain a small current 150 mA or so even if the charge is ended successfully? I've made the test, and the gauge was using roughly 100 mA whereas the FC bit was set. Does it seems correct to you ?

The charge logs format is:

The discharge logs format is:

Thank you again for your time.

Regards,

Christophe

Thomas,

After roughly 15 charge and discharge cycles (100% to 4%), the FCC value seems stabilized (2200 mAh).

The charge time and discharge time are identical for each cycles (max. 5 minutes delta), so the battery pack is healthy and the charging method is valid.

It appears that the issue is related to a wrong calibration method.

Best regards,

Christophe 

Hello,

We use a BQ3050 as a gas gauge for one of our project and we have made some awkward observations concerning some read only registers in the gauge.

For example, the absolute state of charge register is set to 100% after calibration. After complete charge and discharge cycles, the register value is updated. During the charging part of a cycle, the value is increased from 70% to more than 100% (see screenshot in attachment) and then decreased during the discharge part of the cycle to 70%.

In the other hand, for some new gauge, after the calibration process, the remaining capacity, relative state of charge and absolute state of charge registers are set to 0 whereas the cell voltage is around 4V. After complete discharge and charge, the registers are not updated and we don't know how to reset them to the default value to re-iterate the calibration process and use these packs.

Do you already have seen such a behavior and how is it possible to completely reset the flash of the BQ3050.

Best regards,

Christophe,

ASOC is based on the Remaining Capacity and Design Capacity or Design Energy. If it is set to 845%, or reporting erractically, then the Design Capacity or Design Energy must be set incorrectly in the data flash. Are you using CEDV Coefficients to calculate the EDV thresholds or did you set the thresholds yourself? There is a Mathcad program to help set the CEDV Coefficients, if you are using that technique. You can export a gg file and attach it and I can review it for setup errors.

Regards
Tom

Thomas,

We use a 4S1P configuration with four Li-Po 4000mA cells, so I've decided to reuse the default configuration file and just change the charging threshold and configuration in the file. In theory, I must have also changed the Qmax Cell [3..0] and Qmax Pack to 4000 mAh but the gauge automatically tune the Full Capacity register with 3 or 4 charge/discharge cycles.

Below, you will see the difference between the default Texas .gg file (Calibration, Show Default and Export File with the bqEVSW software) and our "custom" file:

CUV Threshold = 2200 To CUV Threshold = 2500 // cells discharging parameters
OC (1st Tier) Chg = 6000 To OC (1st Tier) Chg = 4000 // cells discharging parameters
OC (1st Tier) Dsg = 6000 To OC (1st Tier) Dsg = 4000 // cells discharging parameters

LT Chg Voltage = 12000 To LT Chg Voltage = 12000 // cells charging parameters
ST1 Chg Voltage = 12600 To ST1 Chg Voltage = 16400 // cells charging parameters
ST1 Chg Current1 = 4000 To ST1 Chg Current1 = 3000 // cells charging parameters
ST1 Chg Current2 = 4000 To ST1 Chg Current2 = 3000 // cells charging parameters
ST1 Chg Current3 = 4000 To ST1 Chg Current3 = 3000 // cells charging parameters
ST2 Chg Voltage = 12600 To ST2 Chg Voltage = 16400 // cells charging parameters
ST2 Chg Current1 = 4000 To ST2 Chg Current1 = 3000 // cells charging parameters
ST2 Chg Current2 = 4000 To ST2 Chg Current2 = 3000 // cells charging parameters
ST2 Chg Current3 = 4000 To ST2 Chg Current3 = 3000 // cells charging parameters
HT Chg Voltage = 12570 To HT Chg Voltage = 16400 // cells charging parameters
HT Chg Current1 = 3800 To HT Chg Current1 = 2800 // cells charging parameters
HT Chg Current2 = 3800 To HT Chg Current2 = 2800 // cells charging parameters
HT Chg Current3 = 3800 To HT Chg Current3 = 2800 // cells charging parameters

Depleted Voltage = 6000 To Depleted Voltage = 8000 // 3 To 4 cells deplepted voltage
Depleted Recovery = 6500 To Depleted Recovery = 10000 // 3 To 4 cells deplepted recovery voltage
Design Voltage = 10800 To Design Voltage = 14800 // 3 to 4 cells nominal voltage
Operation Cfg A = 0228 To Operation Cfg A = 0328 // 3 to 4 cells configuration

 According to the configuration file, the CEDV Config register is set to 0x00 which means automatic compensation disabled and detection triggered by the lowest cell voltage.

In attachment, you will find the configuration file. Again, thanks for your help,

Best regards,

Chris.

PS: I'm interested by your Mathcad program. Could you please give me a link to it, I've not found it in the bq3050 page.