battery voltage

My mechanic says that my alternator is sending to much power to the car he says that cars usually run at 14. something not at 15.1-15.5 like my aurora he says i need a new alternator is that for real because the car has always been running like that he says the battery might get mess up if i leave it with the current radiator what do you guys think??

My car has done that for 193,000 miles. I hope nothing is wrong.

when i first got my car at 100k miles the voltage was usually around 14.6-14.7. when i replaced the alternator it now runs usually at 15.1. and i have never had a problem.

the charging system has a thermistor that allows it to charge at a slightly higher rate at colder temperatures... like when there is a greater demand on the electrical system below zero starts, heated seats ,heater motor on high,wipers, and rear window and mirror defroster may all be running at the same time..i have seen mine charge as high as 15.6 and usually in the summer its only at 14.4....i was also concerned before i found this out...