The better converters can be set for the specific parameters of your battery bank (size, quantity, type). Because of this, a converter that is larger than the minimum size needed can be installed with no harm to your current bank, but allow you to upgrade your batteries later and not have to replace the converter. The larger converter will probably run cooler with your current configuration and also have a higher capacity inverter function.
2008 Itasca Meridian 37H & 2015 Flagstaff T12RBST
2011 & 2012 Len & Pat's "One lap of America"
27K miles & 41 states in 13 months - Woo Woo
Yellowstone Lake 6-1-2012