My boat has a 24V DC system, except for the start battery which is 12v.
We have a 24V 175A alternator for the 24V house system and a 12V 30A alternator for the start battery.
I'm thinking that I could use and Orion 24-12 30A charger connected to the 24V alternator to charge the start battery....this would keep a load on the alternator at all times if the Lithium house bank decided to disconnect at any time, and thus protect the alternator - is that feasible?
Your thinking makes sense and is logical, but I don't believe this would work for a couple of reasons, although I'm not absolutely sure as it's a novel idea.
The thing is the Victron DC charger would only take 30 amps max from a spike and that may not be enough, plus it's a charging device so it's not really designed for what you have in mind.
There are devices designed for what you want. Sterling, for example, makes an alternator protection device for either 24 and 12 volt systems and it's much less than a DC charger. I would use something like that in this situation.
