Off-Grid Solar Powered "Smart" Mercedes Sprinter Van

Hello,

Thank you for taking the time to read my post!

I am in the process of designing an electrical system for a Mercedes Sprinter van that me and my wife are planning to build into our mobile, off-grid, tiny home.

I would like to incorporate the use of smart controls into the van. Below are the current specifications.

800W of Solar Panels
450Ah LiFePO4 12V DC Battery Bank
2000W 12V-120V Inverter (ideally, this will not be used all that often, and I don’t want the “smart system” to depend on it. More details below).
The van will have a Verizon wireless hub on board which the smart controller should connect to for uninterrupted connectivity to the cloud.
Smart system should be able to be Alexa controlled

I would like to have smart controls for two different “systems” if you will.

  1. The 12V lighting system - should be controlled EXCLUSIVELY via 12v DC power. (No 120V imput to any DC controllers).
    I am considering using a Fibaro RGBW controller for this. If I do that, is there a Z-wave hub that anyone knows of that can operate on 12V DC to bridge the gap between Fibaro and Alexa?

Additionally, I will have some other devices wired into the 12V system such as a hydronic heater, and the inverter. I would love to be able to control these (On/Off only) on an iPhone remotely. I am guessing that would require installing some wireless 12V relays, but I don’t know if a reliable option exists. I was looking at a Sonoff 12V Wifi switch on amazon, but I have no experience with this. I am not sure how to use a wireless relay in conjunction with a local on/off switch for when there is no internet connection (if a relay is wifi controlled, and there is no wifi, I would need a local option).

  1. A 120V smart system. This would only kick on once the inverter is powered up. The system should include a wireless relay that can power on/off a AC unit. That is the only device I would need to power on/off with the 120V system.

My experience is limited, I am a prior Coast Guard electrician. Military electrical training is better than nothing, but leaves a lot to be desired.

My goal is to create the above system without getting overly complex (I.e. I don’t want to have a ton of different relays all over the van). The optimal solution is one that requires the fewest components possible.

Thanks for any advice you may have!