How to get the battery life of mac os x macbooks p

Question

What I wanted to do is take a log on battery percentage. I know the equivalent in linux is sysctl(hw.acpi.battery.life). However when I went through the man of sysctl in mac os x I did not find the equivalent code to find it. Can some one point out how to do this using objective c. I can call sysctlbyname but that doesn't have this as input in its struct. Kindly help me please

Answer 1

Try using IOKit and the IOPowerSources functions. You can use IOPSCopyPowerSourcesInfo() to get a blob, and IOPSCopyPowerSourcesList() to then extract a CFArray out of that, listing the power sources. Finally you can use the IOPSGetPowerSourceDescription() to grab the dictionary.

If you can use the command line, you can use the pmset command

Like so:

$ pmset -g

Answer 2

Another way to get some more info on battery status is to use NSTask to execute the system_profiler command with SPPowerDataType as the argument. On my Mac, it gives me the following results :

Battery Information:

  Model Information:
      Serial Number: W01396THJD3LA
      Manufacturer: SMP
      Device Name: bq20z451
      Pack Lot Code: 0
      PCB Lot Code: 0
      Firmware Version: 201
      Hardware Revision: 000a
      Cell Revision: 165
  Charge Information:
      Charge Remaining (mAh): 5013
      Fully Charged: Yes
      Charging: No
      Full Charge Capacity (mAh): 5086
  Health Information:
      Cycle Count: 72
      Condition: Normal
  Battery Installed: Yes
  Amperage (mA): -300
  Voltage (mV): 12303

To retrieve what you specifically, you could either parse the appropriate lines, or generate a plist with this command:

$ system_profiler SPPowerDataType -xml > BatteryInfo.plist

This would make it easier to retrieve the values, based on specific keys.

Answer 3

you may use ioreg on the command line as well. For example:

ioreg -l -w0 |grep CurrentCapacity 

gives you the current battery status, which may be compared to the max capacity:

ioreg -l -w0 |grep MaxCapacity