DC/DC or ArgoFet

[Afrinus]

Working on my LiFePO4 setup, I have to decide how to hook up the alternator.
I'm including a FLA starting battery to make sure I always have a load on the alternator should the BMS disconnect the LiFePO4 pack.


My current setup is a 100A Balmar with a MC614, and as I dont want to always run it hot, hooking it up to the FLA starter battery and stacking two DC/DC converters (30A each) to charge the Lithium makes sense.


However I'm re-powering and will include a 170A alternator as part of that effort.


My pack is CALB200AH in 3P4S for 600AH, protected via a REC-Active BMS.
Also, real estate for huge solar is not available on my boat (I will carry about 500W), so I do need that big-ass alernator.



This leads to some issues:

• Having to stack four or even 5 of the Victron DC/DC chargers becomes very cost prohibitive, and the single 100AH FLA is in anyway not capable to supply that much to the LiFEPO4
• If I go with 2 or even 3 DC/DC chargers, I don't really get the gain from that fandangled new high Amp alternator, and I quickly run into limits from the single FLA battery as well.

So, the alternative is to connect the Alternator through a Victron ArgoFET isolator, feeding the FLA on 1 output and the LiFePO4 pack through the BMS disconnect on channel 2 of the isolator.
Now, if the BMS disconnects, the FLA is still in circuit to protect the Alternator.

One other option I'm considering is to change the MC614 to a WS500.

The WS500 can be integrated with the REC Active BMS, allowing the WS500 to de-excite the alternator prior to a disconnect event.
As a safety precaution, going this way, I will still add one of the Sterling alternator protection doodads.

So, how did you guys solve this? Option 1,2 or 3. Or something entirely different?