I have an RV with an existing AGM auxiliary battery connected to the starter battery via a Blue Sea Automatic Charging Relay (ACR). Both are charged via the 220A engine alternator, with the ACR determining which battery requires charging. I have added additional house batteries (LFP) in a separate location and would like to also charge those via the alternator, using a 50A Buck-Boost DC-DC charger (see diagram).
My question is: When connecting the Buck-Boost to the starter battery in accordance with the instructions, how does this affect the existing interface between the starter batter, the ACR, the alternator, and the existing aux battery? In other words, can I leave the ACR in place and simply connect the Buck-Boost to the starter battery per the instructions?