Lithium with Thruster (again!)

[Camille1]

My lead acid batteries have been neglected and uncharged in a med boatyard and I expect are pretty well dead. (Their insurers won't allow mains power unattended charging.) So I propose to replace with Lithium cells.

I have a single alternator which I propose to connect directly to a lead acid and then to a Balmar MC 614 (set for Lithium). From there I intend to feed directly to two 40 amp Daly BMS units.

Each BMS will control 12 cells; that is with each three cells in parallel and with these connected in series making a nominal 12 volt battery. The cells are rated at 100 amp, 2C (max 3C). Each BMS sensor/balancing wire will connect to each three cell unit making four wires per 'battery'.

Nominally, I would have two 300 amp batteries, plus the lead acid.

I also have a 24 volt bow-thruster with a probable load of 450 amps. I have switchgear to series two battery banks so, connecting the Lithiums, it seems I may have a nominal 600amps feeding a 450 amp load, well under 1C and easy on the Lithiums.

Diagrams I see connect both the charging feed and the load supply through the BMS units. Should I connect the load side directly to the battery terminals, or at least while the Bow-thruster is in use? I don't want to drain the Lithiums inadvertently in normal use.

Is this a sensible setup? Do I need a charge splitter such as a Sterling Pro Split R unit?

I would appreciate the observations of the A team out there!

[more]

Originally Posted by Camille1

My lead acid batteries have been neglected and uncharged in a med boatyard and I expect are pretty well dead. (Their insurers won't allow mains power unattended charging.) So I propose to replace with Lithium cells.

From there I intend to feed directly to two 40 amp Daly BMS units.

Each BMS will control 12 cells; that is with each three cells in parallel and with these connected in series making a nominal 12 volt battery.

neglected and uncharged in a med boatyard
------------------------------------------------
you are neglected and forget to disconnect the battery from boat,put some solar panel for charging. and also after this come to boat every 30-90 days.
med boatyard don't have time ,good worker for normal work. But what I sea if you pay 50-100€ per visit you can hire somebody local or marina stuff. Normaly demand next time this person send you 5-6 picture on whatsup every visit for example battery monitor..
(Their insurers won't allow mains power unattended charging
What I know boatyard and marina in med don't have insurers or very rare for customer boats. have insurers for cleaning after fire-sink boat, eco insures and property of marina-boatyard

now Daly BMS 40A common port can handle only 20A charging