Laptop Battery Percentage Reporting

While setting up a Battery test for a Dell XPS 9570 I encountered the following issue:


I wrote a .bat script that automates the battery test job from Windows Assessment Console. The easiest way to do that was using a Web Power Switch that allows you to remotely unpower a Power Outlet, instead of having to physically unplug the charger from the Laptop.

The Charger is never physically disconnected from the Laptop, but the Laptop recognizes/displays it is switching from Battery to Charger a few times during the test.

Unfortunately, it appears doing that process causes an issue where the Laptop Battery won't allow or show itself charging above the % it was at during the end of the test. (This is assuming the Battery isn't going bad in some way by coincidence).

I'll outline what happens when I see the issue:

1. My .bat script sends a command to the Web Power Switch telling it to unpower the Outlet the Laptop Charger is plugged into.
2. It then starts a Windows Assessment Console: Idle Battery Test.
   • The laptop never sleeps/hibernates, the screen darkens, and the laptop battery level is drained from 100% to 95% where the test is stopped.
3. Once the Idle Battery Test has completed, the Web Power Switch is told to restore power to the Socket the Laptop Charger is plugged into.
4. The Dell XPS Laptop is at 100% while the charger is plugged in and receiving Power.
5. Removal of the Charger shows the Laptop at 95%.
6. If you plug the Charger back in, it says it's at 100% power.
7. Leaving the Charger plugged in for hours at this point and removing the Charger results in the Laptop reporting a 95% charge, when it should be fully charged per normal expectations.
8. Performing a Battery Calibration by draining the battery into Hibernation at 2% and then charging the Battery back to full over night returns the battery to 100%.
9. Running the test again repeats the issue.

Updates and thoughts as I tinker:

• What about completely unplugging the Charger from the Outlet and plugging it back in?
• Does allowing the battery % to fall below a certain threshold allow it to be charged back up to 100%?
  
  • I've inserted a 1 hour unpowered pause in the script after the test runs. The intention is to see if dropping a few percent below 95% immediately following the test results in the OS/Battery allowing full recharge once power is restored to the Outlet.
• I did see situations where the Battery Charger was plugged in but Windows showed a 'Plugged in but not Charging' state.
• I think my script should be running a 100% to 85% (or lower) test instead. I think this would address any issue with battery life maintenance software running on the machine that's preventing quick cycling of charges that could otherwise cause issues with the battery. The lowered battery percentage may allow for longer duration between charges and charges starting from a lower percentage.