We have a Model Y and I've been researching this topic for months now. A couple weeks ago we finally purchased a Palomino SolAire eXpandable 147X for use with our Model Y.
View attachment 645058
This trailer has a stated hitch weight of 315 pounds and a dry weight of around 3100 pounds. The two queen beds fold out from the trailer, so inside it's actually pretty spacious and functional with the beds sticking out. And the unit is smaller when folded up, which helps with towing.
From a power standpoint our Y was able to pull the trailer just fine from Portland to Seattle. (The only trip we've taken so far with the trailer). It feels like it's got plenty of power, and even the dealership owner was impressed when I let him test drive the car with trailer attached. We opted for a sway bar, but not the weight distribution system. (Remember, these things add to the tongue weight). There was no problem maintaining control of the trailer, at least for that one ~200 mile drive we've been able to do so far.
The hitch weight was a big concern for me. I really want to stay comfortably within the stated 350 pounds hitch weight that the tongue. So I got rid of one of the two propane tanks, and am looking for replacing the remaining 20 pound tank with an 11 pound tank. (We only take weekend trips so we don't need a very large amount of LP). Each tank weighs 40 pounds fully loaded, so going from 80 pounds to potentially 20 pounds really saves hitch weight capacity.
Next we got rid of the 65 pound lead acid trailer battery and replaced it with a 15 pound
LiFePO4 battery. Even though on paper we lost half the battery capacity (going from 100Ah down to 50Ah), LiFePO4 batteries allow you to use 90% of the battery capacity before tapering whereas Lead Acid batteries only allow use of 50% before taper (and permanent damage) sets in. So I actually consider the battery capacity mostly a wash. And we saved 50 pounds of tongue weight there. After these two changes, our tongue weight is roughly 300 pounds, before adding on the hitch mount, ball, and sway bar, which combine to maybe 25 additional pounds. We don't load any cargo in the trailer with any real weight, so I feel confident about the hitch weight staying below (ever so slightly) the 350 pound limit.
The trailer itself weighs closer to 3350 pounds (instead of the stated dry weight of 3100 pounds) even we we have it empty. I'm not sure why that is. But nevertheless it's still below the 3500 pound towing capacity of the Model Y, so we're meeting that requirement.
The rear of the car does sag noticeably when the trailer is attached. That's probably my biggest concern honestly. We have everything within the Y's stated capacity ranges, so I'm not too worried, but it would suck to suddenly have a tire blow on the highway or something. One thing to consider is that if you're adding 300 pounds of trailer tongue weight to the car, that also adds to the car's payload capacity of 800-900 pounds. So that means that there's only a little over 500 pounds remaining that can be added to the car with humans, suitcases, etc when the trailer is attached. We may end up going slightly over this amount when going camping, but not too much - maybe 100 pounds over the stated payload limit of the car. If we bring anything really heavy with us (metal objects, coolers, etc) we may try loading it in the frunk to not put any more weight on the rear axle.
Finally the biggest hit we've noticed is to our range. Our car is stated to get about 326 miles ordinarily on a charge. However going at about 60mph (in winter and wet weather in the Seattle area) we only got about 100 miles of range. It seemed like we might be able to get slightly over 100 miles if we went 55mph, but that's about the slowest I was willing to go on I-5. This is fine as long as your region is very well covered with superchargers and/or Chademo chargers. We're pretty spoiled here and that isn't really as much of a problem for us, other than having to stop much more frequently to charge. In both cases we were able to pull in and charge without dismounting the trailer, which was nice. The first spot we pulled in to a trailer charge spot, and the second location was empty, so we drove along side the bank of Sperchargers and just charged that way. I believe in the spring and Summer (where weather is 55-80 degrees) our range will improve.
I hope this was helpful to you and anyone else looking to pull a camper with their model Y. Like I said, we've only been on that one long trip so far. As we do more trips over the next season I'll update this thread with additional findings.