I have a boat where I am installing Victron Smart Lithium batteries ( 2 x 200 Ah). I have a Smart BMS CL 12/100 to manage the charge sources ( MPPT 100-50 + and Phoenix IP43) plus loads ( Smart battery protect 12-220)
In all diagrams, input of the BMS is connected to the alternator and the starter battery for power. However, in my case, the output of the alternator is connected to a MOSFET battery splitter , which feeds the service battery, the starter battery and the bow thruster battery from three separate outputs.
Since BMS CL 12-100 takes its power from starter battery connected to the input port, due to the battery splitter, the starter battery will not provide power to BMS unless alternator is running. This means BMS will not enable the chargers and the Battery protec, thus isolating the batteries.
My solution is to have a cable from lithium batteries connected to the alternator input of the BMS with a diode. This configuration did work in my test setup. But I need to get a confirmation that it will not cause any issue before wiring the boat.
Will this cause an issue when the alternator is running