On 6 occasions in the past 3 years, battery was dead after 2-8 hours time elapsed. No precipitating event, jump started each time and all was well for another few months. Battery and electrical system checked out fine. Happened today after overnight in heated garage. Car has 58k miles, near end of lease. Was considering buying it, but not so sure now. No hypotheses from dealer, unwilling to replace battery unless they see the car when it's dead.