There is some easily available information on finding the status of a battery, or weather it\'s charging or not. (GetSystemPowerStatus API or System.Windows.Forms.SystemInformat
just give up and forget this matter. It is not a problem, so dont worry about that. Let it be plugged in and be fully charged. when it is on 100%, then the system automatically stops charging, and goes on the plug power, so, maybe no worry to wear a battery, as all notebooks (if it's not from the XX century) has auto regulation of it. Although, If you will ever need, move you hands and plug it on/off manually. Dont be lazy. That is the #1 and quickest solution, beleive me.
(however, if you want to waste time, here are methods -
1) http://www.makeuseof.com/answers/what-battery-manager-can-stop-charging-at-a-certain-percentage/
2) disable devices temporarily (But you need to disable "Microsoft ACPI-Compliant Control Method Battery")
3) https://superuser.com/questions/813182/how-to-stopdisable-battery-charging-on-laptop