[syshum]

For it to be useful the trailer would have to be more than just a battery, it would need to supply power (as in have an electric motor) as well.

Which would be an interesting concept,

[waiseristy]

Probably not cost effective. You need a lot more hardware than just a ball and hitch to ensure there is no jackknifing or other weird unpredictable behaviors. A lot of work goes into ensuring trailers almost never push forwards against their hitches (trailer brakes are in a large part a thing to solve just this problem)

I bet you could get a fifth wheel hitch to play nice though if the software was tuned correctly

[sp332]

Airstream does have a concept for this. https://www.motortrend.com/news/airstream-estream-electric-d...

[brianwawok]

It does not need to have a motor. Tesla can generate 400-1000+ horsepower, which is more than enough to pull a trailer at 75+ MPH.

Would just need the hitch to include a power cable, to send power back to the car.

[stock_toaster]

Or put an electrical generator and a small fuel tank in the trailer -- like a train.