Would that be a good idea for me . My engine is a 2cyl. 15 hp. yanmar ,the alt. was a 35 amp. my batts. are 2 deep cycle/ starter gp. 27 type sorry I don't know the amp. rating . My power requirements are small . ie. no reefer. The reason I'm asking is that I need a new alt. And my electric guy suggested a 80 amp . alt. I'm not usually away from dock power for more than a day , but when I am I'm gone for 2 weeks . When were gone for a extended time we would just go out for a motor sail , usually for about 2 hrs. and that would bring the batts. up pretty well . What do you Sailnetters think .Thanks .