Thanks for looking into this and sharing what you have found. Very helpful information. I am trying to read info from the same charge controller and having a heck of a time. If you were going to use this adapter from Sparkfun would you just hook up the orange, red, and black wires that you mapped out or is the 5v required for this application? I didn't see 5v being supplied by this adapter which is why I ask. The plan is to use pymodbus on a raspberry pi to talk to the controller and make the information available through json to grafana and my home automation system. Any help with getting the interface to work would be appreciated.