I just installed a set up on our Pearson
385 very similar to what you are proposing for yours.
This is what I chose:
300AH LiFePo4 (12V) house bank
AGM start battery
640Wsolar charging house bank only
gen charging only house bank (boat had wind
gen when I bought her, not sure I would install if not already there)
120A alternator, serpentine belt, with Balmar
charging start battery
60A Renogy DC-DC charger to charge house bank
Xantrex Freedom 2500 inverter
charger wired to house bank
The solar pretty quickly replenishes the house bank. We usually see 100% charge on house bank before 11:00 local time (36 degrees north latitude), running re-fridge 24/7, plus usual lights (all LED)
I have installed an on-off-on switch for the DC-DC charger, so I can choose when to use for additional house bank charging. This switch allows me to select 30 or 60 amp charge rates. At 60 amp house charge, the alternator is putting out 75Amps continuous until house bank is charged, this gets the alternator warmer than I like in summer, to I usually limit charge rate to 30A, requiring less than 40A continuous from alternator.
I have the DC-DC charger programmed for LiFePo4 profile, the Balmar
is programmed for AGM charge profile.
I am still researching which shore power charger to replace the Xantrex Inverter
It is an older unit with no LiFePo4 charging options, and the inverter is a modified sine wave unit.
I do plan to separate charger and inverter though.
The DC-DC charger effectively separates the start battery from the house bank.
My theory is this set up keeps a lead acid (AGM) battery in constant contact with the alternator, eliminating the possibility of a BMS shutdown causing a voltage spike/ current
surge that may, or may not, damage alternator diodes.
For us, if we run the engine
every few weeks, the start battery is quickly charged by the alternator. For longer term storage
, I suppose one could attach a small automotive battery charger to maintain the start battery.
I don't regret, for one minute, the switch to LiFePo. They charge quickly, the voltage remains more constant (and higher than FLA) during most of their discharge. This means lights stay brighter, electronics
are happier, electric
motors run cooler and faster. (think fans and pumps).
Just do your research
as the care and feeding of LiFePo is significantly different from FLA.
Sorry for the long winded reply.