Check all wire terminations and make sure they are clean and tight. ( battery, wires on converter )Check where the battery negative side terminates to the frame ground lug as well
I'm assuming that the battery is in good condition and does not have a bad cell, or that you are not draining it all the way down, then trying to recharge and blowing the fuse because it's drawing more than 30 amps ( my 30.5 has a 45 amp charger)
I'm also assuming you have clean A/C power.
Jim & Kim from Colorado
2014 Eagle 30.5 RLS
2015 Dodge 3500HD SRW 6.7L
Click on my profile for Mods and notes