如何编写脚本实现电脑电量低于20%自动休眠并智能循环触发？

I’ve put together a complete solution that meets all your requirements: auto-sleep when battery drops below 20%, prevents immediate re-trigger after reboot until battery rises above 21%, and runs as a persistent Windows service.

Step 1: PowerShell Script (BatteryGuard.ps1) #

This script checks battery status, manages trigger state via the Windows Registry, and executes the sleep command when needed. It runs in a loop to monitor battery levels continuously.

# Initialize registry settings if they don't exist
$regPath = "HKCU:\Software\BatteryGuardService"
if (-not (Test-Path $regPath)) {
    New-Item -Path $regPath -Force | Out-Null
    New-ItemProperty -Path $regPath -Name "LastTriggered" -Value 0 -PropertyType DWord | Out-Null
}

# Loop to check battery status every 60 seconds
while ($true) {
    # Get battery information
    $battery = Get-WmiObject -Class Win32_Battery -ErrorAction SilentlyContinue
    if (-not $battery) {
        Write-Host "No battery detected, sleeping for 60 seconds..."
        Start-Sleep -Seconds 60
        continue
    }

    $chargeRemaining = $battery.EstimatedChargeRemaining
    $batteryStatus = $battery.BatteryStatus # 1 = Discharging, 2 = Charging, 3 = Full

    Write-Host "Current battery level: $chargeRemaining%, Status: $batteryStatus"

    # Get current trigger state from registry
    $lastTriggered = (Get-ItemProperty -Path $regPath -Name "LastTriggered").LastTriggered

    # Reactivate trigger if battery rises above 21%
    if ($chargeRemaining -gt 21) {
        if ($lastTriggered -eq 1) {
            Set-ItemProperty -Path $regPath -Name "LastTriggered" -Value 0
            Write-Host "Battery level above 21%, reactivating sleep trigger."
        }
    }
    # Trigger sleep if battery is below 20% (and discharging, not already triggered)
    elseif ($chargeRemaining -lt 20 -and $batteryStatus -eq 1) {
        if ($lastTriggered -eq 0) {
            Write-Host "Battery level below 20%, initiating sleep..."
            Set-ItemProperty -Path $regPath -Name "LastTriggered" -Value 1
            shutdown /h
        } else {
            Write-Host "Sleep already triggered, waiting for battery to rise above 21%."
        }
    }

    # Wait 60 seconds before next check
    Start-Sleep -Seconds 60
}

Key Features: #

• Persistent State Tracking: Uses the Windows Registry to remember if sleep was triggered, so the state survives reboots.
• Discharging-Only Check: Only triggers sleep when the battery is actively discharging (avoids unnecessary sleep when plugged in).
• Anti-Flapping Thresholds: Uses 20% (sleep trigger) and 21% (reactivation) to prevent rapid toggling between states.
• Continuous Monitoring: Runs in a loop, checking battery levels every 60 seconds.

Step 2: Set Up as a Windows Service #

To run this script as an auto-starting service, we’ll use NSSM (Non-Sucking Service Manager)—a lightweight tool that wraps scripts into proper Windows services.

Install NSSM: #

1. Download NSSM (match your Windows bitness: 32/64) from its official site.
2. Extract the executable to a folder (e.g., C:\Tools\NSSM) and add this folder to your system’s PATH for easy access.

Create the Service: #

1. Open Command Prompt as Administrator.
2. Launch the NSSM installer:

   nssm install BatteryGuardService
   

3. In the NSSM window:
   • Path: Browse to your PowerShell executable (usually C:\Windows\System32\WindowsPowerShell\v1.0\powershell.exe).
   • Arguments: Enter -ExecutionPolicy Bypass -File "C:\Path\To\Your\BatteryGuard.ps1" (replace with your script’s actual path).
   • Working Directory: Set to the folder containing your script.
4. Go to the Log On tab and select "Local System Account" (check "Allow service to interact with desktop" if you want to see script output).
5. Go to the Startup Type tab and set it to "Automatic".
6. Click Install Service to finish.

Manage the Service: #

• Start the service: net start BatteryGuardService
• Stop the service: net stop BatteryGuardService
• Uninstall (if needed): nssm remove BatteryGuardService confirm

Step 3: Test the Solution #

1. Unplug your laptop to start discharging the battery.
2. Let the battery drop below 20%—your laptop should sleep automatically.
3. Wake it up, plug in the charger, and let the battery rise above 21%.
4. Unplug again; the script will reactivate and trigger sleep if it drops below 20% again.
5. Reboot while the battery is below 20%—it won’t sleep immediately, only after the battery goes above 21% and drops back down.

Notes: #

• Execution Policy: The script uses -ExecutionPolicy Bypass to ensure PowerShell allows it to run. Adjust this if you have strict execution policies.
• Battery Detection: If your laptop doesn’t report battery status correctly via WMI, the script will skip checks until a battery is detected.

内容的提问来源于stack exchange，提问作者Sahil Rajput