I had a 2008 jayco that had a converter that did not go into boost mode and put out a lot of amps to recharge the battery so the 30 amp fuse never burnt out. The pdi in your new tt will see the low battery and go to boost mode of 45 to 55 amps for awhile. This is the reason your fuse is blowing. I have a 2013 starcraft with the pdi and I have been expecting the fuse to blow in it but it hasnt so far. I have a new battery that has not been very low so I expect this is the reason it hasnt blown. my tt only had 10 guage wire from the converter to the battery so I put in 8 guage. You may have this also and could have to upgrade the wire.
