OK, here is the explanation and question.
I am using an old alternator by Delco Remy 12V/50A without internal regulator and use an old external Motorcraft regulator. Everything works, but I have a small dilemma. When I just start the engine the voltage on the output is 14V and later when I cruise for some time, output decrease and stays at 13.8V. This is still valid voltage for this older setup, but I am not sure what is the main reason for voltage decrease from 14 to 13.8V. I can think of two scenarios:
1. Battery is emptier at the beginning because of cranking the engine and if not being connected to shore, so that charging current is higher making voltage a bit higher until the battery is not being charged to some level, but I think this process is not that slow and rather measured in seconds than 10-15 minutes.
2. Since the regulator is above the engine in the engine room where the temperature is higher, when the temperature increase, the regulator decrease the voltage or start switching it on and of (modulating the voltage to 13.8V).
Anyway, I have come up to these two scenarios by thinking for myself, but I would like to know what is really happening if anybody knows. Because I would like that voltage to be a little higher with newer generation of batteries (well up to 14.4V or at least above 14V). Although, this setup works OK for two years now.
I am using an old alternator by Delco Remy 12V/50A without internal regulator and use an old external Motorcraft regulator. Everything works, but I have a small dilemma. When I just start the engine the voltage on the output is 14V and later when I cruise for some time, output decrease and stays at 13.8V. This is still valid voltage for this older setup, but I am not sure what is the main reason for voltage decrease from 14 to 13.8V. I can think of two scenarios:
1. Battery is emptier at the beginning because of cranking the engine and if not being connected to shore, so that charging current is higher making voltage a bit higher until the battery is not being charged to some level, but I think this process is not that slow and rather measured in seconds than 10-15 minutes.
2. Since the regulator is above the engine in the engine room where the temperature is higher, when the temperature increase, the regulator decrease the voltage or start switching it on and of (modulating the voltage to 13.8V).
Anyway, I have come up to these two scenarios by thinking for myself, but I would like to know what is really happening if anybody knows. Because I would like that voltage to be a little higher with newer generation of batteries (well up to 14.4V or at least above 14V). Although, this setup works OK for two years now.