The cool thing about EVs is that they have an instantaneous power meter in them, so there really is no need to speculate. The following numbers roughly corresp

The cool thing about EVs is that they have an instantaneous power meter in them, so there really is no need to speculate. The following numbers roughly correspond to my 2017 Model S: At 30mph the car consumes approximately 200Wh/mi (6kW or 8hp) and at 70mph approximately 300Wh/mi (21kW / 28hp). This is the power required to maintain these velocities against all external factors, and therefore is exactly equal to the power required to tow the vehicle at these speeds. If you have regen set to normal, the car will supply up to 50kW / 67hp through regen. TBH I don't know exactly what the minimum speed to achieve full 50kW is, but I am reasonably confident that the car will do it at 30mph since the tires have more than 10 times the required grip to do it. Towing at 30mph = 56kW / 75hp, 89% charging efficiency, equivalent to a ~2000lb trailer Towing at 70mph = 71kW / 95hp, 70% charging efficiency, equivalent to a ~2500lb trailer The trailer weight estimates are roughly basaed average of engine power / towing capacity figures for medium duty pickups. The tow vehicle to do this safely in my estimation should have a 250hp power plant or larger. The biggest flaw with the linked article is that it's not necessary to go 70mph to achieve the maximum charge rate from regen, and indeed it is less efficient to do so.