My Bene 40 has
a 120 amp after-market alternator that was very poorly installed by the commisioning dealer SOUTHWESTERN YACHTS OF SAN DIEGO. I had to do considerable work to get it right, but in the end, it was worth it. For 150 amps, you'll need a dual belt set-up. You will more than likely need a custom bracket and a new adjusting arm, plus new pulleys, both on the crankshaft and on the alternator. Make sure the belts align dead-nuts or you'll get a lot of wear and black belt dust everywhere. Make sure the adjustment arm is beefy enough and has enough travel to fully adjust the alternator and then hold it there. You will need, if you don't have already, an external smart regulator to handle all that juice, plus the combiner to link house and start batteries to charge from one source. Read up on alternators and battery banks, make yourself an informed consumer and knowledgable skipper, then test it thoroughly, before you pay in full.
