First you said you replaced both 30 amp fuses. DID you unplug BEFORE you replaced them? The reason I ask is that you may really have a 60 amp fuse and if your replace them one at a time with power on they just blow again You must UNPLUG (or disable the converter. easiest way is trip the main breaker) for a period first.. Then replace them.
A test light is your friend when replacing those fuses (Use it to make sure the)
Blown 30 amp fuses suggests either battery installed backwards or shorted cells or a serious short in the converter (in order of how common they are the last rare)
IF it turns out the converter module is shorted the Progressive Dynamics 4600 series replaces just the converter portion of an intergrated power distribution panel/converter.. the 9200 series is for stand alone. These are the best in my not very humble opinion.