I don't see how this would matter, since laptops manage their own charging. My dell sits on either a dock at work or a charger at home all the time (Latitude E6510) so it's *always* charged. My battery still works fine when I take it off. You most likely have a faulty battery. You can't "overcharge" modern laptops. While periodic discharge cycles help a battery, the effect has been mitigated with modern battery technologies and has a very minimal impact. Leaving a laptop on AC power for extended periods of time has no negative effect on modern laptops / netbooks.