Question Charging issues

[Cowboy jeff]

Hi, so my last road trip I had to replace the alternator and batteries
I got it all from the ford dealership and I'm assuming there good, I had this issue before that. But it hasn't been an issue, but after driving all night with the headlights flashing bright/dim and watching the voltage meter jump around from 13.6 to 11.0 I'm very puzzled? Now the wierd thing is when you drop the Rpms the voltage spikes to 13.6 and when I accelerate it drops? What is the normal operating range for the alternator? Why would it produce better at lower Rpms? Is it normal that for
5-10 mins after the first start of the day it puts out 10 volts then eventually powers up?
Any ideas will be appreciated, and any food ideas will be tried
Thanks for the help

 

[Cowboy jeff]

Also I turned on every electrical device on the the truck ( ac, heated seats, fog lights ect, and shut everything down, nothing made a difference except the Rpms ?lower Rpms make more volts , and according to the edge controller there are no codes ( that's what I'm getting the voltage readings from too )

 

[DaveBen]

The electrical system in these trucks is different from any I have seen. First off, after starting the truck, the electrical system does not "come online" for several seconds. Why I don't know. The alternators do product running voltage (13.6 volts) at idle but they don't product much more at higher revs. The voltage regulator see to this. If you think about it for a moment it makes sense; the highest load on the alternator is just after starting. It has to recharge the power that was used by the starter to spin the engine and fire the injectors (and more). Once the engine is running it does not consume a lot of power. The accessories do use a lot.

Dave