Well, your 2000 only has a 10 amp push coming from the 12V dc plug if I
remember right. Your onboard charger is probably about the same! Most
boats only have between 10 and 15 amp chargers because you'd expect to
use it at shore and never need too much more at a time. The times that
you are not aboard lets the charger catch up with your needs.

I don't think either of those ways will do you right. What you probably
need to do is get a big charger but DO NOT GET A CAR CHARGER! Car
chargers will fry your frig and a few other electronics that you might
have plugged in.

Your other choice is a high power alt. If you do that you should get
one of those things that goes between your battery and alt. I forget
the name off hand but it is a big condenser type thing that tames the
power so you don't have lots of static all over your radio and other
sensitive gear.