[BusNit]

We do have basement air which is why I would love to do solar. Fridge is residential but we will replace it with something that does not consume 12.43 amps like the existing one does. We get about 4-6 hours of run time with 4 lead acid batteries. Ideally, it would be nice to run one AC all through the night but even those are high consumption power as they are original and will stay. I guess where I get confused is how to isolate charging from the generator and engine so as not to damage batteries/alternators. I can't find how they (Newell) wired in the charging circuit from both alternators. I only find the large 3/0 battery cables.

[folivier]

You could disable the generator alternator if needed, or put a B2B on that output. If you have enough solar you wouldn't miss it.
IIRC the generator alternator probably just charges the house batteries? I think when I built the LiFePO4 system for my '98 I just disconnected the generator alternator. I changed the main engine voltage regulator to a Balmar which was state of the art back then. B2B are much better IMO.

[BusNit]

Thank you Forest. I wasn't sure how to tackle that one. Perhaps I could repurpose the generator alternator to charge just the engine batteries. But yes, on mine, it does charge the house batteries when running as evidenced by a meter I have on the dash.

[Richard]

Remove the excitation wire on the generator alternator.

The house and chassis batteries converge at the merge solenoid. Someone may have installed one of those large isolation diodes later so that would have to be removed with Lithium.

In my 95 the merge solenoid was merged anytime the ignition was on, that was how Newell charged the house batteries via the alternator. In my 99, the merge solenoid is only activated by the merge switch.

So, check the merge solenoid to see if the center (small) post has 12V when the ignition is on. If it doesn’t you already have manual control of the merge.

Simple to use a B2B charger, hook one side to one side of the merge lugs for chassis, hook the other side to the other side for house.

[BusNit]

Thank you guys. I’ve done much online reading. I do feel comfortable doing this. Most of my questions are getting answered both here and via research. It is also my understanding to install a separate lead acid battery charger that will work when plugged into pedestal. Most important is to keep both chemistries from “visiting” each other except in the event of merging for a short bit to get engine started. My merge solenoid is on a switch and still works. Now the other minor issue is to run battery cables to the basement next to plumbing bay for all the lithium batteries. Finding a route for the cables will prove to be a pain in the ass. I guess the pit will be a great help since I need to go from the inverter under the bed onwards under the coach and over the diff to the rear bulkhead. Had I planned this during the renovation, I could have done something internal with the wiring. Not that 4/0 would be easy to hide…

[BusNit]

As I continue to explore, I found the generator uses the house batteries to start. I would need to move it over to engine start if I were to use Lithiums, correct?

[Fulltiming]

Newell does that to insure that if your chassis batteries go flat, you can still start the generator which you then recharge the house and the start/chassis batteries.

[BusNit]

Ok. So I would just install another separate cranking battery for the generator once I pull the house batteries.

[Richard]

Don’t overthink it. The lithiums will do just fine cranking the gen. Been doing it that way seven years.

[BusNit]

I tend to overthink things. Most of the time I lay awake thinking about the jobs my guys are on and whether or not I need to put my hands on them. just my nature I think! (Except for Fridays. I don't want to know anything then!)