Ubuntu – Battery design capacity is zero

battery

I've a Lenovo G780 unit for which the battery design capacity is reported as zero.
This is a brand new unit.

In /sys/class/power_supply/BAT1 I can find the following information:

  • POWER_SUPPLY_NAME=BAT1
  • POWER_SUPPLY_STATUS=Charging
  • POWER_SUPPLY_PRESENT=1
  • POWER_SUPPLY_TECHNOLOGY=Unknown
  • POWER_SUPPLY_CYCLE_COUNT=1491
  • POWER_SUPPLY_VOLTAGE_MIN_DESIGN=1000
  • POWER_SUPPLY_VOLTAGE_NOW=11820000
  • POWER_SUPPLY_POWER_NOW=635500000
  • POWER_SUPPLY_ENERGY_FULL_DESIGN=0
  • POWER_SUPPLY_ENERGY_FULL=47520000
  • POWER_SUPPLY_ENERGY_NOW=36350000
  • POWER_SUPPLY_MODEL_NAME=
  • POWER_SUPPLY_MANUFACTURER=Li-Ion
  • POWER_SUPPLY_SERIAL_NUMBER=PABAS0241231

At first, I thought that this was a battery issue, but when I use Windows based battery tools, I get good values for the 3 capacity values:

  • design capacity
  • last full charged capacity
  • current capacity

These 3 values are different in windows, so it's not that one of the capacity values is reused for one of the other values.

Any idea what the problem can be? Is this a Ubuntu defect?

Thanks.

Best Answer

The information you get from the /sys interface is what the kernel is getting back from the ACPI battery information from _BIF or _BIX. The _BIF and _BIX objects are normally populated from information from the smart battery which itself is usually gathered over some kind of i2c interface to an Embedded Controller (EC) and the ACPI controls get the data from the EC. So the issue may be in the underlying firmware or ACPI controls.

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