Currently Being ModeratedNov 17, 2012 7:49 PM (in response to acirtaut)
It may be more convenient to try an SMC reset, first.
The SMC (System Management Controller) is the subsytem designed, in part, to control charging of the system. It can lose proper configuration, for unknown reasons< for which a reset is often called for.
If it does not work, seek assistance at an Apple Store, where they will check the system and your charger.