I'm looking to rewire my charging circuit as a result of a burnt battery caused by a rather mysterious wiring scheme on a boat I recently acquired. Won't go in to details how it was wired, but need help on wiring it properly. I have a Volvo Penta D1-20, with a voltage sensing alternator (sensing in image as a yellow line). I'm wondering if connecting the shore power using a Victron Blue Smart charger and the alternator connected only to the start battery bank and then charging the house battery bank (AGM) via an Orion DC DC 12V charger would also charge the house battery when on shore power only. A.k.a would the smart charging voltages put out by the AC charger confuse the DC-DC charger or could one expect that when the AC charger is connected to shore, it would charge the start battery bank and via the DC-DC charger also the house battery in all normal cases (assuming start battery is not in low charge state). I'm looking to configure the DC-DC charger in a way that it will only charge the house battery when the alternator or shore power is connected, presumably using the engine on detection logic. It would never be used as a battery to battery charger. Basic idea pictured below, not including fuses etc, just a rough sketch. Any other solutions are mostly welcome as well. Thank you in advance!