extend range to 500 miles

extend range to 500 miles

I suggest Tesla create a network of portable battery packs/trailers to extend the range of Model S to 500 miles. A network of trailers could be established with GPS capabilities. An app could be used to rent and locate these trailers/extenders from a mobile device. After a user is finished using a trailer, they would charge and post location and availabilty for other users to find/rent. In theory, this would allow a person to drive unlimited miles (coast to coast). I hope this idea can be persued by Tesla product developement.


Sudre_ | January 1, 2013

I don't think there is any way to plug in the trailer to the car. You can not drive the car and charge at the same time and there is no other 'plug' on the car that I know of to connect the trailer to. I think there was a long discussion on this subject in the hopes of getting Tesla to think about it before production. Maybe someone can find that topic and post it.

This is something that can could also be done by an independent company. No need for Tesla to do anything except provide a way to plug the car in and approve the power input.

Reading all the road trip stories so far brings me to the conclusion that it might not be needed. By the time the trailers would be developed and in place the supercharger network will be in place and I'd rather just plug in for 30 minutes. I know some people would rent a very expensive trailer but I don't know if that small number would warrant the creation of them when people will be able to charge in 30 minutes for free after driving for 2 hours or more.

Pungoteague_Dave | January 1, 2013

Towing a trailer cuts gas mileage on ICE vehicles by a lot. My F150 mileage gets cut in half while towing. It would be worse with the Model S, which is highly dependent on aerodynamics for its high range. While a creative idea, adding a battery trailer would be self-defeating. I have plans to add one of the new trailer hitches to our Model S in order to use a hitch bike rack. That setup costs us about 15 mpg with two bikes on our 2011 Prius, so I expect it will cut the Model S range by 25% or more, a trade off I am willing to accept. However, we would never hook up a real trailer, even to haul a motorcycle, behind either the Prius or the Model S.

GLarwill | January 1, 2013

I suspect a much more feasible approach to extending range is more of a better swap scenario. You drive into a "battery station", leave you current battery to be charged and take another, fully charged, with you. Its a different business model where you lease the battery and buy the power it was charged with. Using the recently announced price for battery pack replacement, this works out to ~$125 per month over 8 years.

The station would be able to charge the battery at the optimum rate for best battery life and swap it into another car in a few hours.

You have all the benefits of the quick stops of gasoline, plus the benefits of electric.

jchangyy | January 1, 2013

$125 per month sounds like a lot....especially if you don't drive much to start with. Also, does that mean you can take $10,000 to $20,000 off the initial price of the car since that's about how much we're paying for the battery? if, that's the case, monthly cost makes sense.

lph | January 1, 2013

I dont see a problem with what Tesla is doing. 100 stations in a couple of years. Hopefully they could expand this to say 400 some time after that.
That along with NEMA 14/50 outlets at hotels and restaurant chains / malls, would make life easy for all.
Be patient. Even gasoline did not come over night.

jat | January 1, 2013

You couldn't add it without having high-power wiring run to the trailer, so I think it would have to be Tesla's doing. This was done before -- AC Propulsion had a generator trailer that you pulled behind the car to extend the range.

I think it isn't really needed, and would cut into sales of the 85kWh version and negate the advantage of the Supercharger network. Personally, I would prefer widespread Superchargers than having to tow a trailer around with all the hassles involved.

If you really want to avoid that, it seems more likely to have battery rental/swap locations, similar to Better Place. The Model S is designed to have the battery swapped in about a minute. Better Place works by you only lease the batteries, so battery ownership makes that more complicated -- I would think the only way it could work is you rent a fresh battery and you pick your battery up on the way back. However, that is very capital-intensive (as you have to have a bunch of batteries at every location), and Better Place isn't doing so well at the moment so maybe the finances aren't there for this model.

Brian H | January 1, 2013

That also has been discussed extensively. It really only works as a VERY occasional thing done at a service center, or as a large network of leased batteries like Better Place. But it and its partners are having great difficulty creating such a network even in their 2 demo markets, the tiny territories of Israel and Denmark. Then there is the issue of locking in a single common "form factor".

The "battery stations" have to be fully stocked and staffed, virtually 24/7, and 95% of their time would be spent sitting waiting for the next "customer".

All in all, a very low likelihood development.

jat | January 1, 2013

@BrianH - the battery swap stations don't have to be manned, since at least some of the Better Place swap stations in Israel aren't (you call the service center to initiate the swap).

masonbobason | January 1, 2013

It's true efficiency would be reduced when pulling a trailer, but let's assume you lose 30%. You still get an overall range of 400 plus miles (two 300 mi packs). If you design a trailer that sits low to the ground and equip with low resistance tires, I doubt you lose 50% efficiency. Also, the trailer could be designed to work along with Model S aerodynamic shape. How hard would it be to splice into electrical supply line and add a switch for reserve when onboard batteries are depleted? I imagine the range extender trailer would be needed less than twenty percent of time by most drivers, but having this as a option, without upfront cost, may attract buyers who are weary of limited range.

Pungoteague_Dave | January 1, 2013

It takes a lot more than a minute to change a Model S battery - have you seen all the bolts? Would take a lot of time as it is a sructural part of the car, actually a stressed memeber if I remember correctly, contributing mightilly to its stiffnesss and road feel.

Volker.Berlin | January 1, 2013

Pungoteague_Dave, maybe not just one minute, but it should be reasonably quick. Consider that heavy equipment is needed to operate that battery, anyway, thus releasing all those bolts almost simultaneously with automated gear is not inconceivable.

jat | January 1, 2013

@Pungoteague_Dave - Elon has said on multiple occasions that the Model S battery was designed to be swapped in a minute.

@masonbobason - the batteries cost money, so if you are saying two 300mi packs, presumably you mean an 85kWh battery in the car and an 85kWh battery in the trailer. So, you paid extra for a long-range battery in the car, and someone has to pay ~$40k for the trailer. If it mostly sits unused, the rental fee would have to be very high to make it financially worthwhile. For a similar amount of money, you could build a Supercharger that will serve many more people. Or, just keep those batteries in the same form factor they are now, which will save on costs, and just swap them out.

The battery system can transfer at least 320kW (more in the performance version), so cabling required to do that isn't cheap and it isn't really something you want a pluggable connector for.

So, I don't really think a trailer is practical.

Sudre_ | January 1, 2013

No upfront cost! Now that's not going to happen. It cost extra just for the 60kWh battery to have supercharging. To add the extra LARGE wiring harness, 200+ amp relay and some kind of port at the back of the car would be at least $3 to $5 grand just to have the option. Then you would have to add in some steal for the towing and stopping weight of the battery tailor. Regen would improve.

Tesla has no need to give anything away. There is a waiting list for the cars and it's growing. Just wait to sails actually begin out of the US and Canada.

Sudre_ | January 1, 2013

wow lots of auto-corrected spelling errors! lol

Volker.Berlin | January 1, 2013

This has been discussed in considerable depth... You may want to read (and contribute to) these older threads (there are more):

And some aspects of battery swapping have been rehashed in the context of this thread on the superchargers:

DouglasR | January 1, 2013

Not to mention what it would do to my 0-60 time!

masonbobason | January 1, 2013

Yeah, probably won't happen if had to pay an additional 40k for a trailer. You are missing my point. This would be a bridge product produced in small numbers until batteries become less expensive and charging stations more available. Trailers would be produced in small numbers and used for occasional trips. When the trailer is no longer needed, the user charges it and posts status as available using the mobile app(gps enabled). Anyone needing a range extender could search for availability and would be responsible for picking it up, using it, and posting availability status when finished. Because these would be produced in small numbers (10% of total vehicles sold), the financial commitment would be minimal and maintenance for renting etc nonexistent. Volker.Berlin thanks for policing where appropriate posts go. I'll do better next time.

lph | January 1, 2013

I originally thought that the trailer idea was good, and even suggested that rental companies have a few. But no more. See Volker's posting in this thread and take those links he provided and you will see lots of this discussed in detail.

Quigibo | January 1, 2013

How about some Junk in the Frunk?

Ha--I've always wondered if Tesla could just make drop in extra battery packs for the Frunk and Trunk? Should be simple modules with electrical connections---could be with cooling or not depending on engineering. A couple of hundred pounds distributed front and back in such manner shouldn't effect handling that much as they also would be pretty low mounted in the car.

They could be temporary === like for a extended trip or permanent for the 85K peeps that want to hit 100-115K of power.

This might also be a nice temporary way for 40 and 60K owners to have extra range on an ocassional basis.

But---I think the best is for Tesla and some high tech battery companies to put their heads and $$$$$$$$$ together to increase overall battery storage capacity.....

DouglasR | January 1, 2013

My brother, who owns a Volt, is forever trying to figure out ways to extend the range of my Model S -- his not-so-subtle effort to show me that he made the better choice. In his last email, he suggested that I carry a propane/cng generator in the trunk.

I think I'd prefer to drive my beautiful car, quick and roomy, and if there is no convenient supercharger or nice hotel with adequate charging facilities, I'll take a plane.

Amped | January 1, 2013

Better to make temporary mini supercharge stations, possibly out of a semi trailer with solar parked at rest stops.

masonbobason | January 2, 2013

As much as I love the looks and technology of this car, I can't justify the $ for an around town, short trip vehicle. If natural gas catches on, and I think it will, then Tesla has a problem on their hands. Boone Pickens already has a pretty big head start on the Natural Gas Highway. It will be interesting to see the long term viability of this vehicle after the early adapters are gone. I wish Tesla well.

DanD | January 2, 2013

Like all this thinking outside the box.

However, 100s of Superchargers and hotels with 50amp plugs will do nicely.

KOA seems to be the preferred recharge venue already. Maybe they'll start marketing to Tesla owners directly. They all have pools, many have snack shops and all are off the highway.

DouglasR | January 2, 2013

Some (many?) KOAs have overnight accommodations for those who do not camp or have an RV.