This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

bq40z60 + 7,4v Li-Pol battery

Other Parts Discussed in Thread: BQ40Z60

Hi!

I have connected bq40z60 to 7.4v battery pack with 2400mAh capacity. 

Pack has built-in under voltage and over voltage protections with 4300mV and 2400 mV thresholds for cells.

I used resistor imulator for 2 cells configaration, because I only have 3 wire from pack(+7.4V, gnd, thermistor).

I can discharge and charge this pack.

But, when I discharge it, internal pack protection activates prior to bq40z60 protections and battery pack voltage becomes zero.

So, when I charge it, current is about 10mA and voltage is 0-1mV. 

After that chip needs about 12 hours to start charge battery with normal current. 

As I see there are 2 ways: 

- correct setup undervoltage protection on bq40z60 for my pack.

- make recover process faster. 

Could you, please help me to fix it? 

I would be glad to know both variants. 

Best Regards, Roman

 

  • The default COV threshold = 4300mV and CUV Threshold = 2500mV on the bq40z60. You can tighten the thresholds, if you want the gauge to disable the FETs and stop the charge or discharge. I am not clear as to what you are saying with the chip needing 12 hours to start charging.
  • Sorry, Tom, I was wrong about 12 hours.
    I have to use another charger (BQ24103ARHL) to recover battery from protected state and after that I can charge it with bq40z60.
    I tuned cuv threshold, as you advised, and it's work.