1 hour ago, Ssunrader said:

I did also put a fan on the Victron unit to make sure it didn’t melt down inside the compartment near the battery.

Good idea. I think they’re rated for about 135F max (which means my initial thought about mounting one under hood was a definite no-go). 

I did also put a fan on the Victron unit to make sure it didn’t melt down inside the compartment near the battery.

Bigger wire size (6ga) from isolator to truck. Effectively your charging 2 batteries at the same time through this wire. 8 ga from truck battery to DC to DC and 8ga to house battery. I have a longer run so everything is 1 ga larger. 15 ft from alternator to coach battery I'm using a 12/12/18, works good