The Problem

After not using your laptop all summer, the battery drains completely every night when shutting the lid. This used to work fine.

How to Investigate

Run a sleep study. From an elevated command prompt:

C:\WINDOWS\system32>powercfg /SLEEPSTUDY
Sleep Study report saved to file path C:\WINDOWS\system32\sleepstudy-report.html.

Open the generated HTML file. Mine had a graph looking like this:

Graph showing excessive battery drain

Scroll down and try and find the section that has the worst drain:

Section with 82% battery usage

Click on that row of the table. Find the red box and drill down until you find a culprit

Section with 82% battery usage

The problem, in my case

The Realtek card reader has a driver that doesn’t play nice with Windows 10. You’d think that, being a Surface Book, I wouldn’t have problems like this, or they’d expedite a fixed driver, or pull the bad one.

I rolled back to an older version of the driver, provided by Microsoft.

At least the sleep study tool is pretty good!