MacBook Pro M5 Pro: DarkWake causing overnight battery drain

Hello you All :)

I do have the same problem with darkwakes on battery. It does not happen when I do turn off Wi-Fi and Bluetooth before closing the laptop lid/pressing sleep. Below are my findings using Gemini, where finaly some script is managing turning off/on the wifi/bt automaticly:

Apple Silicon Battery Drain Fix (SMC.OutboxNotEmpty)

1. The Problem

MacBooks (M1 to M5) experience severe battery drain (20-30% overnight) and overheat inside bags due to a persistent DarkWake loop.

Checking pmset -g log reveals repetitive wake triggers every few seconds:

due to smc.sysState.Wake(0x70070000) wifibt SMC.OutboxNotEmpty centauri-beta/ (or centauri-alpha / ARPT)

Root Cause: The Apple Silicon System Management Controller (SMC) and wireless chip handle sleep states hardware-side, ignoring macOS settings like "Wake for Network Access". In heavy radio environments, Bluetooth BLE/Continuity spam or Wi-Fi session drops overflow the chip's hardware buffer (OutboxNotEmpty), forcing hardware interrupts that repeatedly kick the CPU out of deep sleep.

2. The Manual Fix

Physically disabling radios before closing the lid resets the SMC buffer and stops the loop completely. Turning off both Wi-Fi and Bluetooth via the menu bar toggles guarantees 0% drain.

The Automated Fix (Script + Trigger)

This setup uses sleepwatcher to automatically cut off Bluetooth and Wi-Fi the millisecond the lid closes, and restores them within 2 seconds of opening it.

Step 1: Install Required CLI Tools

Install the necessary binaries via Homebrew:

Bash

brew install sleepwatcher blueutil

Step 2: Create the Execution Script

Open the editor:

Bash

sudo nano /usr/local/bin/bt-sleep-fix.sh

Paste the following code, save (Ctrl + O -> Enter), and exit (Ctrl + X):

Bash

#!/bin/bash
BLUEUTIL="/opt/homebrew/bin/blueutil"

if [ "$1" = "sleep" ]; then
    $BLUEUTIL --power 0
    networksetup -setnetworkserviceenabled Wi-Fi off
elif [ "$1" = "wake" ]; then
    $BLUEUTIL --power 1
    networksetup -setnetworkserviceenabled Wi-Fi on
fi

Apply strict system permissions:

Bash

sudo chmod 755 /usr/local/bin/bt-sleep-fix.sh
sudo chown root:wheel /usr/local/bin/bt-sleep-fix.sh

Step 3: Create the LaunchDaemon Config

Create a configuration file to link sleepwatcher events to the script:

Bash

sudo nano /Library/LaunchDaemons/com.powerpatrol.btfix.plist

Paste this XML structure, save, and exit:

XML

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>Label</key>
    <string>com.powerpatrol.btfix</string>
    <key>ProgramArguments</key>
    <array>
        <string>/opt/homebrew/sbin/sleepwatcher</string>
        <string>-V</string>
        <string>-s</string>
        <string>/usr/local/bin/bt-sleep-fix.sh sleep</string>
        <string>-w</string>
        <string>/usr/local/bin/bt-sleep-fix.sh wake</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
    <key>KeepAlive</key>
    <true/>
</dict>
</plist>

Step 4: Load the Daemon into the OS Kernel

Register and run the daemon in the background:

Bash

sudo launchctl load -w /Library/LaunchDaemons/com.powerpatrol.btfix.plist

⚠️ Crucial: Upon the first wake, macOS security (TCC) will prompt you with a dialog asking if sleepwatcher can use Bluetooth. You must click "Allow", otherwise the background process will be silently blocked from manipulating the hardware state.