Voltage scaling and 3.5.5

In mission planner the voltage range for scaling is 2 to 8s. If you’re using a 12s, should the scaling be turned off or enter 42 and 52 for min max? Will it work if it’s out of range?

That parameter depends on the voltage sensor hardware you are using.
Are you sure the voltage sensor can do 12s ? if it can, the manufacturer should have placed that parameter somewhere on the datasheet/user manual.

It’s just a Mauch HS-200-HV sensor, so no problem with 12s. It’s rate to 14s. The voltage multiplier and current multipliers are given for the sensor (calibrated, nice!), but that only assures accurate voltage and current numbers for things like battery consumed, current voltage, Failsafe voltage ans such. I’m wanting to know if the scaling function works for adjusting the Pixhawk’s PID settings as the voltage drops. In the min and max fields it says 2 to 8s so the 12s system is out of range.

It should work, but you will have to enter the numbers manually in the full parameter list/table. Mission Planner tries to prevent people from setting bad values by limiting the inputs on its config and tuning pages, but those limits are not set by the firmware.