Display rate of charge / discharge of an Apple laptop battery

powerConsumption.py

#!python

# To use this, you need Python 3 and also the pyobjc module.
# pip install pyobjc

import objc
from Foundation import NSBundle, NSString
import datetime
import time
import sys

"""
ioreg -l -n AppleSmartBattery -r
To learn about battery time remaining calculations:
   https://opensource.apple.com/source/PowerManagement/PowerManagement-637.20.2/pmconfigd/BatteryTimeRemaining.c.auto.html
To learn about pmset's rawlog:
   https://opensource.apple.com/source/PowerManagement/PowerManagement-637.20.2/pmset/pmset.c.auto.html
hat tip to frogor for the boilerplate :)
... but don't let any of this fool you: pmset -g rawlog is still way more efficient
... HOWEVER, pmset won't show you other interesting info emitted by this script!

Notes:
    * "Selected adapter" and "Adapter Watts" may show stale info from the most recently
      used adapter if the system is not charging (Apple Silicon only?)

    * I don't know what some of the values mean, you'll just have to experiment for
      yourself ;)
"""

IOKit_bundle = NSBundle.bundleWithIdentifier_("com.apple.framework.IOKit")
functions = [
    ("IORegistryEntryFromPath", b"II*"),
    ("IORegistryEntryCreateCFProperties", b"IIo^@II"),
]
objc.loadBundleFunctions(IOKit_bundle, globals(), functions)
kIOMasterPortDefault = 0
kCFAllocatorDefault = 0
kNilOptions = 0

# IOService:/AppleARMPE/arm-io/AppleT600xIO/smc@90400000/AppleASCWrapV4/iop-smc-nub/RTBuddy(SMC)/SMCEndpoint1/AppleSMCKeysEndpoint/AppleSmartBatteryManager/AppleSmartBattery

# M1 Max, maybe others
# ... it moved, maybe for Sonoma. This is the old one.
def oldM1MaxBatteryPath():
    return "/".join([
            'IOService:', 'AppleARMPE', 'arm-io', 'AppleT600xIO',
            'smc@90400000', 'AppleASCWrapV4', 'iop-smc-nub', 'RTBuddyV2',
            'SMCEndpoint1', 'AppleSMC', 'AppleSmartBatteryManager',
            'AppleSmartBattery']).encode('utf-8')

# M1 Max, maybe others
def M1MaxBatteryPath():
    return "/".join([
            'IOService:', 'AppleARMPE', 'arm-io', 'AppleT600xIO',
            'smc@90400000', 'AppleASCWrapV4', 'iop-smc-nub', 'RTBuddy(SMC)',
            'SMCEndpoint1', 'AppleSMCKeysEndpoint', 'AppleSmartBatteryManager',
            'AppleSmartBattery']).encode('utf-8')

# 2013 rMBP and a 2019 16" rMBP
def IntelBatteryPath():
    return "/".join([
        'IOService:', 'AppleACPIPlatformExpert', 'SMB0',
        'AppleECSMBusController', 'AppleSmartBatteryManager',
        'AppleSmartBattery']).encode('utf-8')


def M3MaxBatteryPath():
    return "/".join([
        'IOService:',
        'AppleARMPE',
        'arm-io@10F00000',
        'AppleH15IO',
        'smc@A4400000',
        'AppleASCWrapV6',
        'iop-smc-nub',
        'RTBuddy(SMC)',
        'SMCEndpoint1',
        'AppleSMCKeysEndpoint',
        'AppleSmartBatteryManager',
        'AppleSmartBattery']).encode('utf-8')


def get_battery(path, entry):
    err, details = IORegistryEntryCreateCFProperties(
        entry, None, kCFAllocatorDefault, kNilOptions
    )
    return details, err


def validateIORegistry(paths):
    """
    Check for battery info in the provided list of paths, stopping
    at the first valid one.
    """
    for path in paths:
        #print(f"Trying {path}")
        entry = IORegistryEntryFromPath(kIOMasterPortDefault, path)

        # Is this IORegistry path valid?
        res, err = get_battery(path, entry)
        if err == 0:
            return path, entry
    print("Couldn't find a valid IO Registry path to battery info. Sorry!")
    sys.exit(1)


path, entry = validateIORegistry([M3MaxBatteryPath(), oldM1MaxBatteryPath(), M1MaxBatteryPath(), IntelBatteryPath()])

print(
    """
Displaying power consumption stats every minute.
  Positive charge rate == charging
  Negative charge rate == discharging.

"Time Remaining" means time until full when charging, or time until empty when discharging.
"Selected Adapter" is set to 254 when no power adapter is connected.
"""
)

# fmt = "{:<29} {:<7} {:<4} {:<10} {:<18} {:<18} {:<15} {:<2}"
fmt = "{:<17} {:<7} {:<4} {:<10} {:<18} {:<17} {:<15} {:<2}"
print(
    fmt.format(
        "Time",
        "Rate",
        "%",
        "Capacity",
        "Time Remaining",
        # "Charging Voltage",
        "Selected Adapter",
        "Adapter Watts",
        "Not Charging Reason",
    )
)

while True:
    res, err = get_battery(path, entry)
    if err != 0:
        print(f"Battery polling returned error {err}!")
    # Uncomment the below line to see all the IORegistry data at this path
    # print(res)
    print(
        fmt.format(
            str(datetime.datetime.utcnow())[5:19],
            res.get("Amperage") / 1000.0,
            res.get("BatteryData").get("StateOfCharge"),
            res.get("CurrentCapacity"),
            res.get("TimeRemaining"),
            # res["ChargerData"]["ChargingVoltage"],
            res.get("BestAdapterIndex") or " ",
            res.get("AdapterDetails").get("Watts") or " ",
            res.get("ChargerData").get("NotChargingReason") or " ",
        )
    )
    # IOKit provides new data at 60 second intervals
    time.sleep(60)

❯ python -i ~/bin/powerConsumption.py

Displaying power consumption stats every minute.
  Positive charge rate == charging
  Negative charge rate == discharging.

"Time Remaining" means time until full when charging, or time until empty when discharging.
"Selected Adapter" becomes None when no power adapter is connected.

Time                          Rate    %    Capacity   Time Remaining     Selected Adapter  Adapter Watts   Not Charging Reason
2020-04-13 22:50:19.798078    0.798   99   8404       7                  0                 86              0 
2020-04-13 22:51:19.803939    0.758   99   8404       6                  0                 86              0 
2020-04-13 22:52:19.787836    0.692   99   8404       5                  0                 86              0 
2020-04-13 22:53:19.793269    0.303   99   8403       7                  0                 86              0 
2020-04-13 22:54:19.799085    0.618   99   8403       3                  0                 86              0 
2020-04-13 22:55:19.805651    0.602   99   8403       2                  0                 86              0 
2020-04-13 22:56:19.808222    0.568   99   8403       1                  0                 86              0 
2020-04-13 22:57:19.812074    0.541   99   8403       0                  0                 86              0 
2020-04-13 22:58:19.815651    0.513   99   8403       0                  0                 86              0 
2020-04-13 22:59:19.822129    0.484   99   8403       0                  0                 86              0 
2020-04-13 23:00:19.826928    0.458   99   8403       0                  0                 86              0 
2020-04-13 23:01:19.829554    0.435   99   8403       0                  0                 86              0 
2020-04-13 23:02:19.837048    0.337   99   8403       0                  0                 86              23
2020-04-13 23:03:19.842459    0.385   99   8403       0                  0                 86              23
2020-04-13 23:04:19.847887    0.325   99   8403       0                  0                 86              23
2020-04-13 23:05:19.861549    0.162   100  8568       65535              0                 86              4 
2020-04-13 23:06:19.871665    -0.001  100  8577       65535              0                 86              4 
2020-04-13 23:07:19.879030    0.0     100  8577       0                  0                 86              4 
2020-04-13 23:08:19.887081    -0.001  100  8577       0                  0                 86              4 
2020-04-13 23:09:19.894252    0.0     100  8577       0                  0                 86              4 
2020-04-13 23:10:19.899607    0.0     100  8577       0                  0                 86              4 
2020-04-13 23:11:19.883654    -0.04   99   8576       0                  0                 86              4 

Here's an M1 Max transitioning from battery to AC power.

Time              Rate    %    Capacity   Time Remaining     Selected Adapter  Adapter Watts   Not Charging Reason
07-07 03:37:02    -0.528  19   20         171                254                               128
07-07 03:38:02    8.17    19   20         252                3                 140               
07-07 03:39:02    8.527   21   21         98                 3                 140               
07-07 03:40:02    8.551   23   23         94                 3                 140               
07-07 03:41:02    8.544   25   25         92                 3                 140               
07-07 03:42:02    8.544   26   27         90                 3                 140