Electrical issue.

Start by using a volt meter to check voltange at battery while the engine is running. If you are much past 14.5ish you could have a bad voltage regulator. Alex

Yes - indeed the alternator or ground circuit 'might' be the culprit - however: Only through *hands-on* testing / diagnosis by qualified personnel can this problem be accurately determined. Recommend having local auto repair facility mechanic check it out. Good luck with it!