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STC3117 Fuel-Guage: (STC3117IJT): Issue regarding the SoC readings at the time of discharging

parth.y.shah
Associate II

Hi team,

We are working on a platform based on Qualcomm APQ8016E (Snapdragon 410c) . It is a battery operated device and we are using STC3117IJT in our product. We are facing an issue regarding Incorrect battery capacity indication at the time of discharging.

root@tytodev:~# cat /sys/class/power_supply/battery/uevent

POWER_SUPPLY_NAME=battery

POWER_SUPPLY_STATUS=Discharging

POWER_SUPPLY_VOLTAGE_NOW=3399000

POWER_SUPPLY_VOLTAGE_MIN=2059200

POWER_SUPPLY_VOLTAGE_OCV=3781250

POWER_SUPPLY_CURRENT_NOW=-144

POWER_SUPPLY_CAPACITY=41

POWER_SUPPLY_CAPACITY_ALERT_MIN=10

POWER_SUPPLY_TEMP=26

It looks like the capacity(REG_SOC: 41) is calculated from the POWER_SUPPLY_VOLTAGE_OCV (REG_OCV)

Physically Measured battery voltage (with no load connected, OCV) is below 3.4v which is 1-2%.

We have used the same OCV/SOC table as per the datasheet in our Linux driver.

The percentage tracks during charge, using the voltage OCV, is fine.

But we noticed that during discharge, the voltage-OCV does not reflect the real battery voltage.. And so doesn't the percentage calculate.

On the other hand, the voltage-Now(REG_VOLTAGE) does track the battery correctly during discharge.

We wonder if the percentage calculation is using the voltage-OCV for discharge calculations?

Can it be setup? Or maybe the discharge graph is not correctly loaded to the FG.

We have also attached battery datasheet for your reference.

Please help here to resolve this.

Regards,

Parth Y Shah

4 REPLIES 4
parth.y.shah
Associate II

Any update?

parth.y.shah
Associate II

Any update over here?

parth.y.shah
Associate II

Any update?

parth.y.shah
Associate II

Is there any update?