Check for a loose cable connection at the battery posts and at starter and main ground cable
If you have had the battery cables off of battery for any reason, check that all small wire connectors are back on the battery post along with the 2 main battery ones. It's easy to stuff a small ground wire out of the way while working in the battery area and forget to put it back on
Check the connector to the stator wires plug for good connection.
Check the wires out of the stator by putting a voltmeter on the battery, then wiggling them where they come out of the stator area
Use a volt meter with engine off... a little over 12+ volts?..... start engine up, run a couple minutes then record the volts at 2500 rpm.... 14+ volts?
Are you running a huge amount of lights that would drain the battery?... big audio amp?...
Could be a bad battery or bad stator....under warranty still? From your post, sounds like system is not charging ( doubtful) or battery may have a faulty cell in it ( very possible)
Take 2 aspirins and call us in the morning....lol
sent by a twin turboed RAZR