Is it possibly to have a trailer beheind, and if, than how big?
More than likely, it's possible to tow a trailer just like any other car; BUT doing so will drain your battery faster and diminish your range.
I have towed a trailer for years behind a RAV4EV, and my 1st gen Prius. I have also towed a 5 ton truck up a hill with a Celica. The only consideration with an EV is how much weight the frame will take, and how much torque the car will generate without overheating or damaging the motor and electronics. Most smaller cars limit you to 1000-1500 lb loads and 100-150 lb tongue load. If you want to tow your horse trailer or a ski boat, probably better not.
When I asked Tesla about towing, they said it would be similar to other cars. I imagine it will be determined and published along with other data as they get it further along.
I've heard that the Model S in the shape we all know and love will NOT have a towing hitch. I think this is stupid especially since you can get proper detachable hitches, and BMW 5 series offers this in Norway. So please make sure Tesla takes not that a towing hitch is very handy feature... :)
Roadster doesn't have towing hitch, but I don't think anyone here can say anything about Model S (yet). It is still work in progress.
I seriously hope they offer a (removable) hitch, if not that would be a dealbreaker for me. I only use my trailer for shorter trips so diminished range is of no concern.
The tow rating should be at least 4000 lbs, 1000-1500 is ridiculous. A competing car like for example the BMW 530d Touring is rated for 4400 lbs trailer weight by BMW. My current VW Touran 2.0TDI DSG is rated for 3300 lbs towing and my current trailer for 3100 lbs total weight.
Get a pick up.
My 2005 Mazda 3 is rated for 2,000 lbs, and the hitch has been absolutely invaluable to me. I can trailer my motorcycle to a track, I have helped people move, it got me a huge load of firewood for free, and it has saved me on delivery fees for home improvement projects...and I still get 26+ mpg.
I really want my next car to be a Model S, and with the increase in torque over my 3, I don't think a mounting point for a Class 2 hitch (3,500 lb GTW, 350 lb tongue weight) is unreasonable.
There's a good picture of J B Straubel, co-founder of Tesla, pulling a trailer behind his *Roadster* on a 300 mile pick up of a refrigerator system.
I heard that Tesla will be like other cars: THEY don't put a hitch on. YOU do. When I asked quite a while ago, it was mainly considered "of course" you will be able to put a hitch on. It's up to the hitch manufacturers to recognize Tesla and make a hitch. That's how I got my first hitch for my Prius: They made it for me in the shop while I waited.
It was back in the 80's when you had to buy a hitch separate and mount it yourself. In the last decade or two, most every car manufacurer that sells cars in europe offers factory mounted hitches, mostly removable ones.
With old cars, you could piggy-back the connections for the trailer lights to the cars rear lights. Try that today and the car will probably tell you that you have a broken brake light or something as there are sensors that read the current. You need a proper can-bus interface module for the trailer wiring to work properly or work with a LOT of electronic relays.
Also the car needs to have tow rating determined by the manufacturer. No point in fitting an after-marked hitch if the tow rating is 0 lbs. The police will then certainly fine you heavily if they stop you.
It's different in my part of America. Sorry about that.
My last two cars (2001, 2002) had a tow rating of zero. Have *never* been ticketed in 150K miles of driving. Pulled over once with trailer needing attention because load was shifting, cop saw it and I thanked him.
I just installed a removable aftermarket hitch on a NEW Acura MDX. Made by another company, NOT put on by dealer. Over here, Dealer marks up tow hitch 500% for big profit, you can buy same hitch and install it yourself for 1/10th the money (plus your labor).
Trailer lights? Guess what? You get a little box with wires all ready to T into the tail light circuit, ONLY because in USA we have old style lights (Brake lights are also signal lights), and other countries uses separate signal circuit.
Sorry it's so difficult where you are.
If you get a hitch put on, be sure they weld it correctly, as the alpha pictures show quite a bit of aluminum down there.
Over here factory fitted hitches are only about 30% more expensive than the aftermarket ones, so no point in not going the factory route as you'll get less warranty trouble that way.
If you just T-connect the trailer lights into the rear lights of modern cars most cars will give you an error message about defective lights since the current is different because of the parallell bulbs. Also you might smoke some wires because of the double current. It has nothing to do with how the signal/brake lights are arranged. Modern cars with factory hitches even displays an error message when one of the trailer lights is broken. Like "Left trailer brake light defective" or something like that.
BTW, towing with no tow rating will over here not only get you the fine, but you'll be required to leave the trailer behind and pick it up later with a proper car. Not something one would like to do when far from home...
Also, for a car having no tow rating, hitches won't be sold over here. For example, there are no hitches available for the Toyota Prius.
For the Prius, you tie a little red wagon to the bumper.
I'm not intending to really tow anything, but a factory installed removable hitch would be nice for mounting a good solid bike rack.
What would actually be nice, is have the Model S with specialized trailer wiring allowing the trailer to carry an additional battery
Of course something that interfaced with the computer and provided extra power would need to be manufactured by Tesla, and isn't likely...
The Model S has an aluminum frame. This requires careful attention to details for a hitch such as no iron/steel touching the aluminum directly as the dielectric at the interface would otherwise cause severe oxidation. The strength would be affected if new holes and bolts are placed. (Again remember to check the composition of the bolts is important.) I saw plenty of area with sufficient strength to which a hitch could be attached. Tesla uses special equipment to weld their aluminum together.
The bigger concern I would have is that the skeleton at NAIAS has only a 6 inch/15 cm ground clearance for the battery pack with the wheels and tires as shown. I did note the frame is higher behind the rear axle. I did not measure its ground clearance at this area, but it is higher.
The electric motor has a very high torque and would likely have a correspondingly high tow capacity. The biggest concern I would have is the air cooling of the motor. They could probably give a rating associated with a maximum speed. Tesla might have an issue with giving it a tow rating as they have little money to spend on testing.
Engine is liquid-cooled in Model S. No need to worry about that.
Model S has diffuser in the back, putting something in the way of airflow would probably make it much less aerodynamic and weaken the handling.
An extra battery? The size of the car's whole floor? 900 lbs.? RU mad?
Actually, even though extra batteries in a trailer is mad, the idea of a small powerful gas motor and generator *isn't* completely mad. *IF* there were a great rear power input connection, then the idea of a tight 2-wheel 'generator' trailer would turn the S back into a 'Volt-type' gas-powered long-distance machine, until the charging infrastructure catches up.
Especially cool would be a small gas-turbine driving the generator for exceptional efficiency. Even 1-2KW would help extend a day's trip, and then allow overnight or emergency recharge on such a trip. Larger capability would be better.
The idea of pulling a trailer is plain stupid. The range gained by the generator or battery in the trailer is lost by the miles you have to pull the trailer when you don't need it.
Think about it: You tow a trailer for 250 mi (I guess you lose 50 mi in friction and air drag), after that you lose the same ratio of the energy from the generator or battery for the same reason. You would be better off doing a fast charge.
Also, think about the added cost of such a trailer...
I think dguisinger might have meant a battery in a different format to the Model S battery, i.e. more like the roadster's. Not as a battery substitute but as a range boost when taking trips beyond the car's range. I think given Tesla's all electric, oil free status it would be a shame to start using generators, why are towed battery extensions such a bad idea?
Basically because they are not needed with long enough base range. If you buy such a trailer you don't save anything in money, and installing such battery directly in car is smarter move:
Larger base battery means two things:
1)You can use lower power density batteries for same power output, which means cheaper, higher energy density batteries (saves weight and money).
2)Any charging is made in lower rate of charging and less of max capacity of battery prolonging the battery life.
To make that point clear think about Volt 40 mile battery compared to Model S 300 mile battery. Each charging is made 7 times higher rate for Volt battery using same charger, and Volt battery needs to withstand 2500 DOD cycles to last 100 000 miles, when Model S requires only 333 DOD cycles at that same time.
With ranges over 300 miles it becomes convenient to charge in route. Just basic three phase 400V@32A would give you 22kW charging which means ~200+ miles in just two hours, and with fast charger infrastructure being build much less time if you find one of those in route.
If you get such a battery trailer it would pretty soon turn out dead weight behind your car that nobody wants. Basically money used to wrong thing.
Just as point of interest, the Toyota RAV4EV was fitted with a trailer, with a Kawasaki motorcycle engine hooked to a generator mounted on it. The Kawa would rev up, the generator pumped power into the regeneration side of the controller, and you could drive 70 mph all day. No, that's wrong: the gas didn't last that long.
The noise was excessive, the weight was prohibitive, the trailer and equipment was quite expensive, and you got to fill up with gas every so many miles. It did NOT sell. It did not even rent. People found it far easier to plan their excursions around standard charging (6.6 kW, no fast charging), and doing restful things while the car charged.
People drove from Frisco to Lake Tahoe, Frisco to LA, LA to Oregon, all in a car with a 100 mile range. No trailer.
The motor control electronics will certainly monitor motor and battery temp - thus, I expect that the Model S will have a fairly significant trailer rating... with the caveat that the electronics will warn you to slow down when things get hot - and then power will be reduced if temps continue to increase. I doubt that Tesla will recommend long-distance trailering... but for many of us, we need to get the boat in and out of the water and haul it for storage each year - that should be no problem.