Solar panels
From Wildsong
Morningstar charge controller Renogy Wanderer 10A Charge controller
10W panel
32W panel
Charge controllers
Renogy Wanderer 10A
PWM charge controller, costs about $20 Should work fine with LiFePo4 battery (or any Pb battery)
https://www.renogy.com/wanderer-10a-pwm-charge-controller/
Serial port
I wrote to service.renogy.com support and asked for more docs and got a pinout. A good start.
They did not come up with protocol specs but there seem to be some projects that have implemented access to the controllers.
https://www.reddit.com/r/SolarDIY/comments/vxc8h1/renogy_wanderer_rs232_port/
https://github.com/BarkinSpider/SolarShed/blob/master/RenogyWanderer.py