The Xantrex (and most others) relate the size of the inverter function with the size of their charger function; and,
What sized alternator are do you have?

As I (inartfully) wrote below:

i) The face rating on a charger is overstated. Unless Xantrex has changed, they promptly drop to an effective maximum charge of less than 60% of their face rating. (For example my Heart 130 Amp unit would only charge at less than 70 Amps. -- but before you curse Xantrex, my Mastervolt 200 Amp charger is good for only about 130 Amps of effective charging.) At least the larger units, have internal heating issues.

ii) I think that it would be mistake, IF YOU ARE REPLACING THE UNIT AND HAVE THE ROOM, not to up the sizing a bit. If you pull into a marina and want to recharge your batteries over night, you might not get there with a small unit if you really empty the batteries down.

The smart charger will protect the batteries if you oversize the charger a bit. If you get an external controller for the charger, then you can set the unit for the size of your bank (that's helpful to see how much capacity you have, without doing some math on the "real" voltage.)

Make sure that your golf batteries are in a well ventilated place too -- especially if they are conventional lead-acid units.