Using TV inverter to power fridge while towing Do or don't?

if you have a tow package and 7 pin
the battery should already being kept charged

if your thinking of inverter in the TT

25 amps is 25 amps from the alternator, no matter where the inverter is located

if your TT battery is running down while driving
you need to find out why ?
then run the additional charge wires if needed

other people have done this, sometimes there is too much voltage drop
from alternator to TT, the batteries barely get a trickle charge