BB-x15 temps and voltages

X15 Temperatures and voltages

uname -r = 4.14.49-ti-r54

I am monitoring /sys/class/thermal/thermal_zone5/temp with conky. I believe
this is the temp that triggers a 5 volt fan to come on at 40C.
I have seen enough to know I am going to install a fan (hopefully quiet) to
run continuously and keep the temp hopefully below 32C. The fan will be
running from an external 12 volt source for now.

Now a question; how much can the X15 deviate from the 12volt input voltage?
I am wanting to use the X15 in portable situations in car or golfcart for
starters. Later with a LiPo pack.

Looking at the TPS54531 I see the input can vary from 3.5 to 28 volts.

Second question; where can I find reference material on

Thank you