mine goes from just below center in the summer (25C) and just over center in the winter (-25C)

 

I have a 03 dodge ram 5.7 my resting voltage 14.4 but after i drive about ten minutes if it is over 50 mph it goes in limp mood and take a out 45 minutes before im good to go for another 10 minutes but a new alternator in it and battery is about 4 years old any idea what it is i know the pcm regulates the voltage but is there anything else to look into before i deem the problem pcm

 

What codes are you getting?

 

Are you reading 14.4V with the engine off? If so, try turning the lights on for a minute then test again.
You shouldn't get a reading above 12.8 with the truck off.
Your battery may be bad (thermal runaway) and causing truck to go into limp.