If you have been towing an RV for a long time as we did in the 70's and 80's, you know you have two or three issues. Wind resistance, weight to accelerate and move uphill, and rolling resistance from the tires of the trailer. Depending on how level the area you are crossing is, the weight of the tow will be factor. The direction and velocity of the wind conditions along the route will vary each trip in each direction. I suggest that projecting consumption will be difficult. While your trips by ICE vehicles may have been a run for the hills after work on Friday, Going slower so you can go farther may be the answer you have not considered. You probably already know that the faster you go the more force is required to overcome drag. Rivian is not as aerodynamic as any Tesla. Thus range will be much better at 55 mph than at 75 mph.I've posted fairly often regarding range and towing, and why I believe I need the Max battery pack to be able to successfully tow even my smaller teardrop over longer distances. There is still not a huge amount of data available regarding power consumption and range for Rivian towing, and most of what I've seen is based on towing larger, bulky loads. Their consumption figures are not encouraging, with most at or even below 1.0 mi/kWh. There is a Youtube video of a family towing a 30' Airstream with an R1T that was encouraging however. The figures they posted were in the 1.3 m/kWh range.
I recently had a on-line dialog on another website with someone towing a teardrop that is similar in design to mine, though quite a bit longer, wider, higher and heavier. Their tow vehicle is a Tesla Model Y, and they report consumption averaging 370 watts per kilometer. If I'm doing the conversion properly, that would be about 592 watts/mile and would in turn mean a theoretical max range with a Rivian LR Large pack of 228 miles. Using 80/15 charge/discharge parameters brings effective range down quite a bit, but still to a very respectable 150 miles.
Am I making a mistake in my calculations? As importantly, am I making a mistake using the Tesla as the basis for things? I'd think that the larger and heavier Rivian, regardless of whether it was the R1T or R1S, would better the Model Y, or at least be no worse. With my teardrop being smaller and 1,000 lbs lighter than the one towed by the Model Y, I'd also think that at the least, using the Tesla figures would be very conservative.
The bottom line for me is that if I could get those numbers towing my [email protected] 320 with a Rivian LR Large pack, I'd gladly forgo the wait (which could be indefinite) for the Max to become available.
It was not difficult for us to forgo the max pack, we prefer not to move around the extra battery weight every time we move the Rivian, once we get it.