BQ27542EVM: BQ27542EVM: BQ27542 RSOC drop from 27% to 0% at low temperature

Hi,

Sorry but we can offer limited support on this issue. I recommend you do the following, select the best ChemID, complete a learning cycle with the entire pack, run the Ra0 tweak and the Rb tweak, and then continue to run charge and discharge cycles on the battery pack. The gauge will continuously update the resistance tables and you should see the SOC jump improve over time.

You can also manually tweak T rise and T Time constant and see if these help improve performance at low temp. Typically these are adjusted by Rb tweak, but you can also tweak these manually.

T Rise gives the thermal rise factor that is used in the single time constant heating-cooling thermal modeling. If set to 0, this feature is disabled and simulations in the IT algorithm will not account for self-heating of the battery cell. Larger values of T Rise lead to higher temperature rise estimates for the IT simulation.

T Time Constant is the thermal time constant that is used in single time constant heating-cooling thermal modeling. The default setting can be used, or it can be modified to improve low-temperature accuracy if testing shows the model does not match the actual performance. T Time Constant defaults to 1000. This is sufficient for many applications. However, it can be modified if better predictive accuracy at low temperatures is desired.

Regards,

Evan