The purpose of the R7, R8, C7 circuit going from the 12v bus to pin 26/A7 of the Arduino is to act as a voltage divider for the Arduino to sense then display the?input voltage.
Buried in the documentation for the Forty-9er is a line that the circuit was added to act as a voltmeter but the code hadn't been implemented yet. Jack and company have been very busy and just haven't gotten around to it. I'm in the process of writing that code and will let y'all know when it is ready. Version 1 will be just a voltmeter. For Version 2 I have some ideas to add undervolt and overvolt warnings.
As of right now I'd just ignore it. Ran the numbers for the voltage divider and no matter what the setting of R8 is there is no chance of damaging the Arduino as long as you don't apply more than 15v.
Till later
Hank K5HDE
