7

Ubuntu shows the remaining battery time on my desktop as ~2 hours.

I was trying to arrive at this same value from /sys/class/power_supply/BAT0/uevent. The output of cat /sys/class/power_supply/BAT0/uevent for that instant:

POWER_SUPPLY_NAME=BAT0  
POWER_SUPPLY_STATUS=Discharging  
POWER_SUPPLY_PRESENT=1  
POWER_SUPPLY_TECHNOLOGY=Li-ion  
POWER_SUPPLY_CYCLE_COUNT=481  
POWER_SUPPLY_VOLTAGE_MIN_DESIGN=7400000  
POWER_SUPPLY_VOLTAGE_NOW=7400000  
POWER_SUPPLY_POWER_NOW=9361000  
POWER_SUPPLY_ENERGY_FULL_DESIGN=48248000  
POWER_SUPPLY_ENERGY_FULL=40877000  
POWER_SUPPLY_ENERGY_NOW=20712000  
POWER_SUPPLY_CAPACITY=50  
POWER_SUPPLY_MODEL_NAME=UX32-65  
POWER_SUPPLY_MANUFACTURER=ASUSTeK  
POWER_SUPPLY_SERIAL_NUMBER=

I was assuming the POWER_SUPPLY_ENERGY_NOW value would be in Watt. How do I work out the remaining battery time from this?

JJT
  • 181

1 Answers1

8

Power now = 9.361W, energy now = 20.712Wh. Remaining time is 20.712 / 9.361 which is approximately two hours.

PeterJ
  • 245