I plan on switching my boat’s 200AH wet cell house bank to LiFePO4 and keep the wet cell for starter. Both banks are currently wired to a single 1-2-All-Off battery switch with lead cable from a traditional (not smart) alternator and out to positive buss bar. If I connect the Orion TR to the starter (”1”) battery positive to charge the house bank underway will I need to keep the switch on “1” underway and then to “2” when the engine is off and I’m using the house bank?
Assuming that all your loads (including the starter motor, engine and house loads) and the alternator are connected to the switch, I'd say you're on the money.
A better setup might be to have your starter motor and engine electrics connected to the start battery, then all your house electrics connected to your new lithium house battery. Then use the DCDC to sit between the two. The switch would then not be needed under normal use so it could be used to select between "All" and "Off" so that you can start from the house bank if needed by selecting "All".
