Did we ever arrive at a consensus on this? I’m planning to dive in with a local RV Electronics guy. We talked through my original plan for 12V, and mostly due to the wiring size and age, arrived at doing a 48V System, stepping down for the 12V house, and using a Victron MultiPlus to step up to the 120V AC for what would primarily be for Air Conditioning.
I’m editing this post now, because we found the Victron unit for 48V was not a 4 post 50 amp input, I didnt’ want to downsize the input to 30Amp. Which may have been silly…. But I’ll own the silliness.
So we went with the 24V Victron Quattro, which has full 4 post 2 AC inputs, for 50 amp Generator and 50 amp shore power.
As my RV Electronics Expert, who I’d wholeheartedly recommend if your in Southern Oregon Coast, said. “Anything is better then 12V” for stepping up efficiently to 120V and keeping wire sizes reasonable from front to back. So, we went with what the Victron Quattro came in for the true 50Amp Passthru.
We used the Sterling unit same as below—but the 24 volt version, which is actually a little more efficient and so we got a little more charging speed to the battery bank out of it, and still low enough amperage that the factory power cable from front to the back batteries will not need to be replaced.
He’s proposing using this Sterling unit to draw from the Alternator, so the size of the existing lead would be ok using the 48V (changed to 24V) back to the Battery.
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That he says would simplify yet keep the Start Boost Feature functional.
Making sense yet?
BUT—he didn’t want to do it unless I upgrade the Alternator, modern, efficient, and a fresh bigger wire to the Starter Battery. The Sterling Unit will replace a bunch of stuff on the engine bay, right by the battery, and convert the 12V Starter Battery to 48V and feed the house batteries like a DC to DC converter, with the added functionality of generator and house batteries being able to charge the starter battery too. The 48V house battery could also boost the 12V if needed for starting boots. The existing wire running back to the house battery at 48V the wire size would be more than adequate to charge the house battery.
There is a 50% charge rate setting on the Sterling unit, and I talked him into proceeding without changing the Alternator yet. The alternator was done in 2017, and presumably it’s the 100A version of the original.
Update: I bought a 260Amp alternator from Chad, phone number further down in the posts in this thread, who makes the bracket and alternator sets for the GMCRV… That solves a host of issues. He sells them with 2 belts, so I’ll try to use both of those…gets lots of grip on it.
This system would use the Victron MultiPlus II 48V unit, Victron Shunt, and a Victron Dc to DC 48V to 12V converter to power existing 12V house loads.
Changed to the Victron Quattro 24V 50amp unit…Shunt, and 24 to 12 V dc to dc converter for house lights. I went with all LED lighting—that really added up amperage draw with the ancient incandescent bulbs.
