Why did my headlights kill my car?
Ok then I would say no issues with the charging system. You see an alternator with 1 of 3 phases burned up will charge 11.5- 12.0 volts which will charge the battery enough to not appear to be a problem until you put a load such as the headlights on it. But also check the voltage with it running about 1000 rpm if you see more than 14.2- 14.5 volts the regulator is not controlling the alternator properly.