How to connect Renogy Wanderer (RS232 port) using USB/DB9/RJ12 cable to Home Assistant?

I have a solar setup in my Camper which is entirely Renogy components. The blue tooth app is unusable as it loses connections constantly and generally doesn’t work well.

As a result I’ve been looking for options and decided on HA running on a Raspberry Pi4, and booting off of an SSD.

I have a USB to DB9 cable, a DB9 breakout connector, and an RJ12 connector combined into a cable going from the USB on the Pi to the RS232 port. Only Rx,Tx, and GND are used on the RS232 cable.

So my question is, now what ? I have Home Assistant running with a bunch of things installed. So I have an idea of where things are in HA. I just don’t know what I need to do to get HA to see the USB port data and then use it to create graphs in Grafana as an example.

I also have a Custom Repository installed from github for the Renogy Rover (which I also have, that also uses RS232), if that helps.

Can someone help me understand the work flow here? Do I use MQTT? Not really sure where to go from here.

I have an IT background but just haven’t played with this sort of thing.

Here is the list of devices I eventually want in HA. Renogy DCC30, Rover 40A, 2x 100AH LiFePo4 batteries. I also have the BT-1, BT-2 and Hub setups. If they can be used, then great, that’s another option. The BT-2, Hub, DCC30, and Batteries use the RS485 over RJ45 unlike the Rover and Wanderer which are on RJ12/RS232.

Any help is muchly appreciated!

This seems pretty close to what I need to be doing, but it’s not for HA, so not sure which parts of these instructions I can omit (do I need NodeJS as an example)?