I noticed awhile back that the "Primary AC Use" option in Dell Power Manager no longer functions after working for about a year. The battery stayed charged at around 70%. A few weeks ago I noticed that it stays at 100% now. I unplugged it to let it drain down, but then it charges to 100% again. I changed to setting, then changed it back to see it that would get it to work again, but to no avail. I gave up and am using the "Custom" setting now. Why did this handy feature stop working?

I read the relevant parts of this manual (https://www.dell.com/support/kbdoc/en-il/000177768/guide-to-dell-power-manager) that was provided in another thread, but it was not helpful as it is very basic.

I'm using a G5 that I purchased just over a year ago.