communication with solar charger

[joshua-8]

I don't expect to be able to write much code until we have access to the solar charger. I'm just making this issue now as a place to put research and documentation.

Renogy is surprisingly supportive on their support forum of people making projects that interface with their chargers
(i’ve never heard these terms before, so don’t trust this, but it seems that) the charge controller has an rj45 (ethernet cable style) plug and uses the RS-485 electrical interface with the Modbus communication protocol so you can ask it for data or change settings according to this reference from Renogy.
Just some of the information supposedly available is current and voltage from solar panels, current and voltage to battery, battery charge state, even some longer term data
(power to inverter is the only thing that would have to be measured separately)
charger

[joshua-8]

need to find a ttl serial to rs-485 converter
need to find documentation on charger data port (what pins? what voltage? is there a standard?) (maybe contact renogy?)

[joshua-8]

not confirmed, but possible pinout: https://github.com/wildmountainfarms/solarthing/blob/master/other/solar/resources/DCC%20Charger%20Modbus%20RS485%20V1.7.pdf