Hello, sometime the battery icon come on then go out, ac plug was not removed and did not lose power on ac side. Battery saves the computer from shutting down, if I remove the battery and the icon come up the computer shut off. Battery has no problem being charge.
Sounds like it could be an issue with the power jack on the laptop or a bad AC adapter. It can be an expensive proposition to buy a new AC adapter from dell, so if you can find someone with who has the same power adapter, give that a try and see if that solves the issue. If that doesn't solve it, chances are that it is a bad power jack on the laptop itself.
I have three dell inspiron 8100; I try all 3 ac adapters.
I remove motherboard To look at power jack, power jack is not loose or badly soldier. Is there contact inside power jack that switch over when ac power is disconnect. Or is there a circuit board that handles that.