Hello Rocky Healey,
We also have a 2008 Beaver Patriot Thunder Concord IV. I can give you what we did due to the fact we had a complete solar system installed. We replaced the Big Boy and the MAGUNM inverter/charger system. (and some other solenoid installed by the last owners. No idea what they were trying to do but you will see in the images)
We removed the MAGNUM system and replaced with all Victron. Next we replaced the Big Boy with a GEN2 LiBIM 225 batter isolation manager. It seems to match up great with the victron system.
Images;