We're new owners of a 1999 PSC40. As part of our DC overhaul, we'd like to add a 2nd high-output alternator for a 4x 4D AGM house bank and isolate our existing Hitachi 80-amp alternator to charge a Group 27 or 31 AGM cranking battery. The local shop is recommending an AmpTech 125, but I originally wanted to use a much beefier Balmar. However Yanmar apparently doesn't recommend adding a dual-pulley to our 4JH2-TE engine, so that leaves out all of the 9x series Balmar.
Does anyone have any experience or recommendations on this topic?