Can Charging Rates be Changed.

[M80]

The Viano was originally fitted with AGM,
it had a wet cell when I bought it.

It charges at 14.2 - 14.3 volts, this drops to around 12 volts after a while.

So since the original rate should have been 14.7 volts I wonder if the charge rate is changeable, on Star.

It seems time for a new battery, so picking up the correct battery is important. At 14.2 volts charging an AGM wouldn't be it.

 

[sonic]

A fully changed cell is 2.2 volts or 13.2 volts on a 12 volt battery. But that is is in ideal conditions 100% battery condition & 68F air temperature.
So to get to 13.2 volts you need to charge above that rate ie 14.2 volts. As the battery reaches fully charged the charge rate will drop.
I dont see you can change the charge rate on Star, its set by the battery requirement.