On my Lenovo laptop, running windows 7, I got a prompt saying that, the system has noticed I am mainly using adapter, therefore I should keep the battery half charged. It justifies by saying, trying to overcharge batter reduces life time.
Now, form what I understand, the battery and charger should have internal circuits to prevent attempted over charging in the first place. Then, why is there a software level prompt to set the option to "half charge" battery, if mostly running on adapters.