I have several banks of batteries on a boat, two larger banks
48v electric propulsion system with regen
12v house bank
Each has a charging source the 48 has regen up to 2kw while sailing The 12 has 120amp alternator They are set up and running well but isolated from each other. When either of these charging sources are running, I would like to charge both banks at the same time to make better use of the high output.
Wondering is this is a feasible solution: 12 to 48 alternator -> use a charger that is activated by the ignition (https://www.powerstream.com/dc-input-charger-12v-48v-1250w.htm) 48 to 12 regen -> a charger with a manual switch? or programmable VSR? (https://www.powerstream.com/DC48-12-charger-extreme-60A.htm)
OR would a DC/DC converters with voltage sensitive relay / isolators be better? 48v Batteries are valance lifpo4 12v are deep cycle lead acid