I have had and driven an EV9 for 1 week but not towed with it, but range effect of towing with any EV is dependant on the type and size of the trailer. It is important to note that shape and wind resistance have more of an effect on range than weight. In other words, at the same weight, a flatbed trailer, even with a large object on it, will be more efficient than a large enclosed and boxy trailer. There was a video about this a while ago, but I can't remember what it was called. With that being said, generally speaking, towing a trailer with an EV cuts range in half, but like I mention above the trailer type will make a big difference. If you tow a collapsible camper that gets pretty flat when closed your range won't be affected much, as compared to hauling a 20 foot long camper that does not collapse down onto itself and causes a ton of wind resistance. I know it's not the definitive answer you are looking for, but I hope it helps.