BQ27426: how to set the parameters for battery learning?

Dsg current threshold: This defines the current level where the gauge detects that the battery is being discharged. It is set as a percentage of design capacity in 0.1Hr rate units. Current [mA] = Design Capacity [mAh] / (0.1 * Dsg current threshold) For example, if you have a 3000mAh battery and you use the default setting of 167 then the minimum current that your system needs to draw from the battery for the gauge to start coulomb counting is 3000/16.7 = 180mA. If the current is below this threshold then the gauge will treat the battery as relaxed and perform regular voltage lookup to determine remaining capacity (and SOC).

Chg current threshold: Similar to Dsg current threshold but in the charge direction. Set this to below the minimum charge current. It is in 0.1Hr units (so if your minimum charging current is for example 300mA for a 3000mAh cell, this number will be 10 * (3000/300) = 100.

Quit current: If the current falls below this threshold (either charge or discharge current) (for Quit Relax Time) then the gauge will stop coulomb counting and go into "relax" mode (voltage lookup). Set this to a value that is below your system's active current and below the system's minimum charging current. There must be a hysteresis between Quit current and Dsg/Chg current.

Design Capacity: Set this to the nominal capacity from the cell's datasheet (at room temperature)

Design Energy = Design Capacity * nominal voltage (from the battery datasheet e.g. 3.7V - where the cell's voltage curve is "flat").

Terminate Voltage = Voltage where you want the gauge to report SOC = 0% (this should be between 3.4V and 3.0V)

Taper rate = current where your charger stops in the constant current phase. Set this approx. 10% higher. It is in 0.1 Hr rate of design capacity. So if your charger stops with a current of 275mA and your battery capacity is 3000mAh, this number would be 10 * 3000/(1.1*275) = 99.

Taper voltage = minimum voltage for a full charge termination. Set this about 100mV below the constant voltage from your charger. 

Thank you.

Taper rate = current where your charger stops in the constant current phase.

Do you mean voltage here?

taper rate should be the threshold that the gauge considers the battery to be full charged, right?