CIM_Battery WMI Class has no instances

Question

I am trying to create a C# Application that records the battery percentage over time, and to do that I have been trying to use the .NET WMI API. I looked on MSDN and found that there is a WMI class called CIM_Battery, and confirmed its existence with wbemtest.exe.

Upon closer inspection in wbemtest.exe, it appears that the CIM_Battery class doesn't have any instances that I can read from.

Is this normal, or is my system just broken?

Answer 1

Not sure why that isn't working, but another way to do it:

System.Diagnostics.Process process = new System.Diagnostics.Process();
System.Diagnostics.ProcessStartInfo startInfo = new System.Diagnostics.ProcessStartInfo();
startInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
startInfo.FileName = "cmd.exe";
startInfo.Arguments = "/C powercfg /batteryreport";
process.StartInfo = startInfo;
process.Start();

This will output the battery life to a file: C:/Windows/System32/battery-report.html

You can then scrape that page. It's a bit overkill, but there might be more data in there that you can use for your diagnostics.

Edit: also a powershell class in .net (System.Management.Automation) assembly. So you could make a .ps1 with the line: (Get-WmiObject win32_battery).estimatedChargeRemaining

PowerShell psinstance = PowerShell.Create();
psinstance.AddScript(scriptPath);
var results = psinstance.Invoke();

Edit2: The CIM (common information model) classes are parent classes upon which the WMI classes are built. win32_xxx classes monitor and manage system hardware and features and are located in in CIM. Instead of pulling from CIM_Battery parent class, pull from the win32_battery class instead.