My hull nr. is #18... As I bought the boat, I also had the 175A alternator and it was the same problem.
There was also a package from Amel with a replacement to this alternator. Mastervolt 110A and its regulator. In order to install the new alternator, you have to release the Volvo Engine from its place and connect the alternator on the left side of the engine. At this solution, you use the same belt that is used for the sea water pump.
It is not such a simple solution but if you are interested, AMEL will be for sure able to help you with more information.
Sharona, A54 #18