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BQ40Z80: BQ40Z80 no communication at -7℃

Part Number: BQ40Z80
Other Parts Discussed in Thread: BQSTUDIO, EV2400


The customer test with BQ40Z80.

The test purpose: the battery pack low temperature -30 ℃ discharge data collection

Experiment equipment: EV2400, SMBUS communication cable is about 70cm, bqstudio (version 1.3.101)

Experimental process: EV2400 is placed outside the thermostat, and during the cooling process, data is logged. When the temperature is displayed at -7℃, the connection of the host computer is interrupted, and the communication cannot be reconnected even after restarting. (Test battery pack discharge at low temperature, this phenomenon must occur)

The data and error messages of the cooling process are as follows:

The schematic and gg file as below:

Why the battery will lost communication at -7℃ ?

Waiting for your reply.



  • Star,

    Is it possible to provide a logic analyzer output of the bus? The logs don't seem to indicate that anything would be wrong with the gauge, and the fact that communication was working makes me think that the schematic should be fine as well. Is your customer using the EVM? If not is it possible to replicate this behavior on the EVM?