Batteries: The best of both to extend our range??

Batteries: The best of both to extend our range??

There has been talk about battery swapping as a way to quickly 'refuel' on a trip. Tesla at this point is not going in that direction and no Tesla owners would consider dropping off their own new expensive battery for a used rental. I understand that. But what if we were able to have the best of both worlds?

I read in these forums about how much cargo space the "S" will have, so what if Tesla made a 'rental battery' available for us to use anytime we needed more range than the battery we picked for our car affords us. Think of external gas tanks on a fighter jet. Pilots use them to augment their distance, but when empty they switch over to their internal tanks. Maybe that analogy isn't great but, we can do something similar. If Tesla designed a rental battery which could be configured to fit in either the front or rear trunk, and assuming the hookup could be done easily, maybe we could add another 50, 100 or more mile range to our 'internal' battery. And if there were different swap out stations along our route, that would be much quicker than even waiting for a 'quick' charge. Yes, it would add another 500 or more pounds to the weight of the car, but heck, we have a lot of cargo room, right? It might not all be used for luggage. That might just be the compromise we need to give us complete freedom on the road. Your thoughts?

BryanW | 02. Februar 2012

Perhaps something like this?

Take the above with a little re-design... It could come in several flavors. A set on Li ion batteries as a direct range extension, or a gas generator that can recharge the batteries (Volt style), or a combination of both. If it's a battery pack, the pack could be designed for rapid swapping of rental batteries. Thus, you would only take the trailer for long trips, and at quick swaps you only exchange rentals, thus you never touch your precious Model S battery pack.

Interestingly, as built in the link, the trailer can only charge your car while parked, as it won't charge while driving. So, such issue would need to be overcome to range extend in real time...

Of course, it would also have to come with 19" and 21" wheel options to match the Model S.

BryanW | 02. Februar 2012

For that matter, you could just make the whole trailer a rental. Drive up, disconnect, reconnect, go...

TonyF | 02. Februar 2012

@ Bryan, that link is really intriguing.

EdG | 02. Februar 2012

No problem discussing this - again - but remember:
Default operation doesn't allow charging and driving at the same time. Some override of normal operation would be necessary.Much of the engineering of the battery system includes a heat pump to keep the battery running at optimal temperature. This function, if it exists in an add-on, would have to be taken by the add-on.When people go on long trips, they often fill the available storage in the vehicle. Some planning for not doing so would have to be done.If the battery were kept inside, the handling and, especially, the safety of the car would be compromised.There are no plans to allow the Model S to tow anything.

Timo | 02. Februar 2012

That is what Tesla is planning for Model S. You could rent a bigger battery pack to your car for longer trips, and when you are done swap back to your original one. Model S battery pack is designed for fast swapping.

With tech advancing fast and 400-500 mile batteries coming available soon I don't think we need to stuff additional batteries in trunk. 500 mile range at freeway speeds (60-75mph average) is a breakpoint where you are better off taking a break in driving and charging it when it is closing empty than just swap and continue driving. Tiny adjustment to habits for 1% of people, rest wont need to do even that.

I will never ever put a ICE in my BEV. With ICE you need to worry about exhausts, vibrations, intake air, cooling, sound muffling, fire hazards etc. etc. No such worries with batteries.

Larry Chanin | 02. Februar 2012

Yes, very interesting ideas. I can picture a streamlined rental trailer specifically adapted to Roadsters. The trailer would extend range, it would have its own electric motor to furnish propulsion so there's no strain on the Roadster, and of course it would provide that all-important extra storage space that the Roadsters lack. If Tesla were to design such a trailer, (assuming there were no insurmountable patent issues) I doubt that
they would incorporate a gasoline powered generator.


David M. | 02. Februar 2012

Or, you could rent an ICE vehicle for the long trip you make a few times a year.

Volker.Berlin | 03. Februar 2012

Rinspeed comes with a comparable idea to Geneva Motor Show 2012:

Brian H | 04. Februar 2012

Really clever; I bet he'd sell dozens!

Waymond | 05. Februar 2012

Here is a portable charging station or range extender that one can tow on a very long trip.



gjunky | 21. Februar 2012

@Timo: TM has stated in an email that they will NOT be renting battery packs so this option is out. Another reason to question TMs love for the 40Kwh pack (which needs this the most)

Allowing the car to take a charge while driving (or power the car from another source while driving) would be the first step to a range extender.

There was a previous discussion:

olanmills | 21. Februar 2012

I wonder if swapping will really make sense because some people are predicting that something like a Model S with a range of 1000 miles is not that far away.

I don't think it's that far fetched. The Model S can already go 300 miles. If the Model S is successful and their car lineup and customer base grows, battery prices should come down faster, especially as both more battery manufacturers and car manufacturers get in on the electric vehicle game. Competition and demand is going to push these guys to solve the problems and make cheaper batteries with larger capacities and cars that use the energy more efficiently.

David M. | 21. Februar 2012

I've driven cross country twice now. First time 3,000 miles DC to San Francisco. Second time, 2,500 miles Tampa to San Diego.
If I ever do it again, I will be renting the largest, most comfy car I can afford to rent. I would not recommend doing 60 hours of driving in any sedan. Something like a tricked out Mercedes Sprinter Van will do just fine.

At this point in my life, the most driving I would ever want to do (in a sedan) in one day is about 275 miles.

Timo | 21. Februar 2012

@gjunky, what exactly did they say in that mail? If they say that you will not be able to swap batteries for long trips and then get your original back they are eating their earlier words.

Battery rental like Project Better Place is out of the question, you need to buy your battery pack with the car, that has always been the case.