The charging would be FAR more efficient if you simply ran a heavy gauge line directly from the engine compartment to the TT.
Think about it.
You are going to jump 12 Volts DC up to 120 Volts AC, then use that AC power to convert back down to 14-18 Volts DC to charge the Trailer battery.
So, we you jump up you lose energy.
Then when you down convert you lose energy.
Where does the "energy" go? It is lost as heat. Remember the laws of physics, you don't get something for free.
While the previous statements are all absolutely true regarding the output wattage of the inverter, they all sort of missed the point.
Even if you were to plug the TT into the trucks "outlet" and run the converter off your inverter, the converter is doing what? CONVERTING the 120 V AC current into 12V DC.
Long story short, it would be a waste of battery power.
Craig T. Bailey
2015 Jayflight 32BHDS
2007 Chevy 2500HD Crew 4x4 Z71