In Python, how can I detect whether the computer is on battery power?
If you want to do it without win32api
, you can use the built-in ctypes
module. I usually run CPython without win32api
, so I kinda like these solutions.
It's a tiny bit more work for GetSystemPowerStatus()
because you have to define the SYSTEM_POWER_STATUS
structure, but not bad.
# Get power status of the system using ctypes to call GetSystemPowerStatus
import ctypes
from ctypes import wintypes
class SYSTEM_POWER_STATUS(ctypes.Structure):
_fields_ = [
('ACLineStatus', wintypes.BYTE),
('BatteryFlag', wintypes.BYTE),
('BatteryLifePercent', wintypes.BYTE),
('Reserved1', wintypes.BYTE),
('BatteryLifeTime', wintypes.DWORD),
('BatteryFullLifeTime', wintypes.DWORD),
]
SYSTEM_POWER_STATUS_P = ctypes.POINTER(SYSTEM_POWER_STATUS)
GetSystemPowerStatus = ctypes.windll.kernel32.GetSystemPowerStatus
GetSystemPowerStatus.argtypes = [SYSTEM_POWER_STATUS_P]
GetSystemPowerStatus.restype = wintypes.BOOL
status = SYSTEM_POWER_STATUS()
if not GetSystemPowerStatus(ctypes.pointer(status)):
raise ctypes.WinError()
print('ACLineStatus', status.ACLineStatus)
print('BatteryFlag', status.BatteryFlag)
print('BatteryLifePercent', status.BatteryLifePercent)
print('BatteryLifeTime', status.BatteryLifeTime)
print('BatteryFullLifeTime', status.BatteryFullLifeTime)
On my system that prints this (basically meaning "desktop, plugged in"):
ACLineStatus 1
BatteryFlag -128
BatteryLifePercent -1
BatteryLifeTime 4294967295
BatteryFullLifeTime 4294967295
The most reliable way to retrieve this information in C is by using GetSystemPowerStatus. If no battery is present ACLineStatus
will be set to 128
. psutil exposes this information under Linux, Windows and FreeBSD, so to check if battery is present you can do this
>>> import psutil
>>> has_battery = psutil.sensors_battery() is not None
If a battery is present and you want to know whether the power cable is plugged in you can do this:
>>> import psutil
>>> psutil.sensors_battery()
sbattery(percent=99, secsleft=20308, power_plugged=True)
>>> psutil.sensors_battery().power_plugged
True
>>>