There's no standard for power between trailer and vehicle. You're probably looking at a 400V DC connector, which is going to need to be fairly tough, because yo

There's no standard for power between trailer and vehicle. You're probably looking at a 400V DC connector, which is going to need to be fairly tough, because you don't want to electrocute someone. You can't just borrow the existing DC charging connector, because most of them are on the side of the vehicle, and are also set to not allow the car to move if connected. You'd probably need a DC/DC converter to bring the trailer voltage to match the vehicle voltage, or you get the trailer ending up charging the vehicle (and that'd be bad if you don't have something to regulate the current flow). Or you'd need to have another entire drive inverter set to run the motors off the trailer power, and have no HV connection. And lastly, it's almost certainly better in the long run to just improve the charging infrastructure so there's a stop when you need it. That said, your small trailer might be handy for things like: you're actually towing something, and being able to have the trailer supply power to offset the air resistance, would be handy.