landyacht318 wrote:
The OP is considering and dreaming the wide range of possibilities available :), and trying to see what is possible.
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If I go the Dual alternator Route, I'd desire to just have the current 50/120 alternator feed only a dedicated Engine battery, and the secondary alternator would feed whatever battery I use for a House battery. My fear of this method is the shared Ground of both alternators screwing with the ECM's voltage regulator. I fear the magic smoke escaping from the engine computer.
If this fear is unfounded, I'd put an adjustable voltage regulator on this house battery dedicated alternator to give me that manual voltage control I desire. The alternator possibilities would be much wider, but anything more than 70 amps is not really necessary.
But all of this is dreamery. Never the less it is fun to seek the ideal possibilities available.
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If the only connection between the two is the shared ground, there will (well, at least there should) be no problems whatsoever. The ECU would not see the second alternator at all. I'm assuming in this case that you would not also have the two batteries tied together via an isolator system, since there's no need to do so to charge the house battery. (If they are tied together, then the shared ground is not the only connection and things get a bit more...umm...complicated.)
It's no different than the 120VAC ground being shared with the 12VDC ground in terms of the systems interacting with each other—they don't if that's the only interconnection.
