I struggled to find anywhere on the web detailing how to set up a second battery monitor with Pixhawk; I’ve managed to get it working so thought I’d post here to help anyone else who might be trying to do the same.
My use is on a boat running Ardurover v3.1.2 where I want to monitor the 12v drive /pixhawk battery system and the 24v payload battery system.
2 x Mauch HS-100-LV power modules
2 x Mauch 2-6s BECx
Setup for the 12v drive/ pixhawk battery monitor is standard as described in the Wiki.
For the second payload battery monitor I’ve used only the I out (current), V out (voltage) and ground from the Mauch, connected to pins 14 (current), 13 (voltage) and ground on the ADC 3.3v aka ADC pins 2 ADC IN,3 GND, 4 ADC IN.
The setup in mission planner is the bit I found confusing. The Wiki says use pins 14 and 13 but when you look at the options for second battery monitor under optional hardware tab there are only options to select pins 12 or 13. I couldn’t find out where pin 12 is on the pixhawk.
So in the full parameters list I just put in ‘14’ even though the notes say options are 0~A13 and it works! After entering this setting the dropdown box for that pin setting in optional hardware is greyed out.
Also, I can highly recommend the Mauch power modules and Christian Mauch has given me great customer service!
Hope this helps someone with a similar problem.