[Oletrucks] Voltage Regulator question

[Bob Chansler]

I have noticed lately when driving around that my ammeter never dips to discharge and when driving at normal speed. It is quit a ways into the charge zone. Even with the lights on and at idle, the needle stays on the charge side. I measured the voltage on the bat terminal and it is 13 volts at idle and 15.5 at 1500 rpm. My manual doesn't say what it should be. Do I need a new regulator? Any advantage to switch to an alternator?
Thanks,
Bob Chansler
Mead, CO