BQ40Z50-R1: Why Valid Charge Termination Condition has met,but the VCT and FC not set 1.

john xiao

Part Number: BQ40Z50-R1

Dear All:

I use BQ40z50-R1 design 4S2P LiFePO4 battery pack. the Capacity is 7800mAh.

this is gg.csv file:BQ40z50-R1.gg.zip the ChemID is 0438.I set the charge Term Taper Current is 100mA and Charge Term Voltage is 250mV,plug in 14.6V adapter Between Pack+ and Pack-.when the AverageCurrent is 46mA and the Maxcellvoltage1..4+Charge Term Voltage is 3993mV>3650mV.the screenshot as follows

Why Valid Charge Termination Condition has met,but the VCT and FC not set 1?

over 7 years ago

0 Matt Sunna over 7 years ago

TI__Guru* 81034 points

Hi John,

From looking at your .gg file, I see that the cell overvoltage protection threshold is set to 3850mV. If your cell voltage is measuring 3993mV, then your charge FET has likely been switched off. Your charge termination voltage is set slightly higher than your overvoltage protection.

This should address the issue, but if you run into additional issues, it will also be good to post your log file (Click the 'Start Log' button in the registers window) which will show what is happening over time.

Best regards,
Matt

0 john xiao over 7 years ago in reply to Matt Sunna

Intellectual 470 points

Hi Matt:

the 3993mV is one of the Valid Charge Termination Condition,not the Real battery voltage,when the RSOC is held 99%,the Max cell voltage is 3743mV,not COV.

while the AverageCurrent is 46mA.please help check the gg.csv file,Is there anything that needs to be changed?

Thanks a lot.

0 Matt Sunna over 7 years ago in reply to john xiao

TI__Guru* 81034 points

Hi John,

I'm a little confused - I'm not sure where the number 3993mV is coming from? Also, in the .gg file Lifetime data, it does show cell voltages exceeding the overvoltage condition. Can you record and send a log file? The log file will show us what is happening.

Thanks,
Matt

0 Matt Sunna over 7 years ago in reply to Matt Sunna

TI__Guru* 81034 points

Hi John,

Are you able to send a log file? Let me know if you still need help on this issue.

Thanks,
Matt

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BQ40Z50-R1: Why Valid Charge Termination Condition has met,but the VCT and FC not set 1.