Wow I like that, better than the one I put in (I put in a USB charger that shows the input voltage):
Although I could replace the other 12V socket with the same thing and just hook up the house battery instead of the chassis battery.
(of course that would mean our Axis would have 14 USB chargers available LOL).
Looks like
this is the one (Amazon) that you put in.
Hey look they have
one that measures voltage and current (Amazon)
or
one that looks like a rocker switch (Amazon as well).