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Elon Musk has mentioned that the use of Superchargers will be free for owners of ALL (future) Tesla EV models (S, X, Gen3, etc.)

I remember having heard him say that in one of his interview's.

But I just cannot remember which particular interview that was (must be several interviews actually).

Therefore I would like some help of you guys to find that particular interview in which we can actually hear him say that.

Thank you for your help

bent - what size, in kWh will these batteries be? This is all hyperbole and meant to sound good but is fiscally unsound. Is zombie apocalypse in the business plan? You need about 100 kWh of batteries per car per full charge. It takes 20 KW of solar running all day to full 100kWh on a good sun day. Undoubtably, this is just a sound bite that now has too many legs associated with it. Most people don't understand what the battery component actually means.

Well, more seriously then, if they can get the batteries at a reasonable price (and if anyone can, Tesla can) then they would be useful for buffering up electricity from the solar panels at times when the spot price for selling them into the grid is poor. They can then instead sell the electricity at peak times when the price is good. On the flip side, when there's a lot of charging going on and they need to buy power off the grid to cover demand they can start by using power from the batteries that was purchased when electricity was cheap.

They could even do some basic arbitration by filling the batteries from the grid when power is cheap, and selling it back when it's expensive. This is made more complicated by Teslas arriving to get charged of course but might still be doable.

Obviously the maths need to work out for this to make sense, and if they don't then Tesla won't go for this just yet.

I don't remember anyone giving hard numbers for how much battery capacity would be installed on a typical super charger.


"I don't remember anyone giving hard numbers for how much battery capacity would be installed on a typical super charger."

The answer to your question is: 500 kWh. Elon Musk said this during Q&A of the Conference Call at the Supercharger announcement in May 2013.

Power outages, and buffering in high demand spikes, plus storing power off the grid at cheapest TOU rates.

How does storing 500kWh make any difference, other than some momentary buffering? At about 10 charges, it is not enough to store power from lower overnight rates to have any meaningful impact on daytime charges.

I can see where you have 10 stalls (600kW max load) and the grid connection is limited to 400kW, a buffer would allow it to average 400kW while spiking to 600kW. But not sure how that would justify the cost of 500kWh of storage.

As far a selling power at prime rates by buffering with batteries, I do not see the linkage to SCs. If someone wants to generate power (solar for example) and use batteries to store that power to sell back at more opportune times, why not do it at a location independent of the SCs? Surely SC location considerations are different than a solar/battery power generation location considerations.

Drifting off topic a bit, but how would it be possible to pay for batteries with the difference in electric rate from solar, particularly when peak solar generation is pretty well aligned with peak electric rates already? And why wouldn't a utility simply install batteries on the grid to acheive the same thing?

It has been discussed on the TMC forums that the swap batteries might be used as the buffer batteries. And the grid backup always has the same volume/kWhs in batteries.

Time of Use (TOU) and varying rate arbitrage allows the subsidizing the costs of the system (which are very modest.)


200 US Superchargers $150K - $250K = $50,000,000

200 Solar Canopies $150K = $30,000,000

Battery swap/buffer = 500kWh x $250/kWh = $125,000/SC = $25,000,000


Swap $60 each


There is a charging technology reason as well. A charge rate of 120 kWh is not the top of the mountain. A higher charge rate will be possible in the future. And to achieve this Tesla Motors will add stationary battery packs to the Supercharger stations. But that is still a few years from now. The question is what will those stationary battery packs be made of (chemical/mechanical/electrical/software engineering). Anyhow, more super high-tech and interesting stuff can be expected from Elon Musk and his co-workers. And I am already looking forward to it.

@SamoSam - Aren't there other costs as well to your scenario?

200 swap stations $3,000,000 (construction, robotic mechanism) = $600,000,000
10,000 Tesla batteries (50 per swap station) $20,000 = $200,000,000

That would add $800M to your $100M estimate - but we could subtract out the $25M you put in for battery buffer and use the batteries in the swap station for that.

@Benz - Tesla seems to top out around 90kW on the chargers now, so they still need to find out how to turn it up by 1/3 just to get to 120 kW charging. And that is for when a battery is less than 75% charged - the last 25% is slower than that and will remain a challenge. But I think that is why they have 2 stalls per 120kW charger, and with a large location like Gilroy there will always be cars pulling in and out (not in use) and near the top (using less than max charge).

I don't see residential EV's being a big deal for the electric grid or for electric generation. I figure if I were 100% electric my electric consumption would be 30% higher. With residential electric being 34% of total electric usage in the US, that would be a 10% electric increase if all residential was 100% electric.

By the time that happens, there will be a lot more solar distributed around the grid and in residential areas; EV charging can be an interruptible load (or even reversible) to balance the grid (built-in batteries on the grid - no need to add more).


Where did you get the cost of swap is $3,000,000/station ?

Under your scenario with 50 85 kWh packs you would have each swap backup at 4.25MW of backup

That's much higher than had ever previously been disclosed.

I also assumed universal swap which is not consistent with Elon's prediction of putting them in Hugh traffic areas.

@SamoSam - I made up the $3M number. I figured the cost of land, construction, electric hookup and gear, and robotics to handle the movement of the batteries would run at least that much.

If a swap takes 90 seconds, I figured 25 swaps in a peak hour. If they charge 10 simultaneously that would require 1mW power feed (100kWh to charge including loss). In 3 hours they would charge 30 and give out 75, using 45 from charged inventory.

So, take a high-traffic area like Gilroy, which would have a swap station and 16 supercharger stalls. At peak time, they would need a 2mW power feed (8X120kw for the SCs, and 1mW for the swap - and that is using the buffer from 50 85kWh packs.

In 3 hours with 2mW draw from the grid, they could charge 48 cars in the SC stalls, and 80 in the battery swap (50 from charged inventory, and 30 that got charged in the 3 hours). At the end of the 3 hours the swap station would require 5 hours at 1mW to charge the 50 depleted batteries assuming no swaps.

128 cars in 3 hours is the capacity of a small gasoline station that has 6 pumps, and it can operate continuously at that rate. The "steady state" for this swap station scenario is 10/hr with a 10 battery buffer. That could be increased to 20/hr if we give the swap station a 2mW feed.

As far as I know all the new Supercharger stations are equiped with 120kWh chargers.

There are not going to be many swap stations. Probably only one swap station for promo and testing purposes.

The costs for land and buildings (think Jiffy Lube size building) is just not realistic for Tesla to build these all over the place. It was purely a demo for other reasons. Tesla will be one to test whether anyone uses it enough to justify the expense, it will be hugely cash flow negative, then the concept will die.

We can forget about swap batteries being used for buffering on superchargers. It is financially illiterate. The grid doesn't need it. Wasted money for tesla to do it that way.

+1 JamesM. Swap will never be rolled out - it is marketing optics and tax strategy only, with huge logistical and financial hurdles. The existing cars are not set up to have automated swap - would require modifications, and then the swap stations would have to be staffed like a jiffy lube, as the coolant has to be flushed, bled, bolts replaced, torque values verified (the battery is a stressed part of the chassis). The demo was PT Barnum stuff at its best - way more happened there than what you could see. The tech who did my battery swap said it is specified at 3 hours and actually requires 5 hours.

I think it's much too early to start talking about swap stations yet. But eventually, they will be there.

The tour guide at the Tesla factory tour in Fremont told me last week that Tesla Motors is currently working on logistics around pricing, who owns the battery, etc., and when that's all figured out then battery swap will go forward.


There you have it. Thanks for posting this info.

The new Superchargers at Gilroy (expansion) are all 120kWh chargers.

The next Supercharger to go live is Silverthorne, Colorado.

The swap system needs a nut-runner (robot), a space to hold the batteries and a place to park. Not a Jiffy Lube. A space the size of a single Supercharging slot and battery storage. Enough with the FUD.

Agree with Benz and Gill Sans that they are coming.

Yes, the space the size of a supercharging stall, and the underground space under the entire 16-stall supercharger station to store the batteries and chargers.

Very doable, just no ROI at any swap price that would

5 mins and a swap for $x, or 45mins and a charge for free while you pee and stretch your legs.

I'd love to see them put one at Gilroy where there seems to be high demand to test the market.

They will do so when the time is right.

The charges are to be local price of 15 gal of gas, and an additional fee if the swap is an upgrade and you decide to keep it.

That sounds reasonable, although most people will prefer a free fast Supercharge, I think.

Has Tesla announced the location or timing of their first battery swap location?

I think that will be the only way to really assess whether people will make use of swap of supercharge.

First things first (Supercharger stations), and battery swaps isn't one of them.

I even think that the first battery swap station will not go live before 2015, but it might go live in 2015.

There have been skeptics of battery swap, saying the 90-second-swap video was all smoke and mirrors.

Since Tesla spent all that money developing the automation, why not use it? They could put it on a popular route (heading from CA to Vegas?) and see if people would swap in one direction, and swap back in the other.

It could double as their battery replacement center for people that want to upgrade or replace their battery, or that need a warranty replacement. I have seen it reported that it takes 5 hours to do it manually - 90 seconds is a nice labor savings.

They could easily do that in 2014. If their swap program is active, they would. My guess is they never had plans to do anything beyond the announcement and demo. And if they did, my guess is they would be rethinking it based on their difficulty with supercharger rollout. Swap stations are a MUCH bigger challenge:
1. Capital
2. Zoning / Permitting
3. Power
4. Commercialization of the technology. Even assuming the demo was legit, taking it from demo to a commercial installation is a big step.
5. Paid on a use basis, vs Superchargers that are paid for in advance with the purchase of the car.
6. Competition. Superchargers are free; it is difficult to compete with free.

#5 is the biggest challenge. If nobody ever used a supercharger, Tesla would be ahead of the game with some savings on electricity. But if people don't use the swap stations, they have built costly infrastructure with no revenue stream.

We might indeed see a few swap stations on certain popular routes. But the priority lies surely with making progress on the layout of the Supercharger network. A small percentage of owners of a Tesla Model S will be interested in battery pack swapping. But on the other hand, even a small percentage can turn into huge numbers if the total number increases (of annual sales of Tesla EV's). That will happen when Generation 3 comes around (2017).

nick, why do you think so? 100,000 Model Ses would give Tesla $2,000 * 100,000 = $200,000,000 just for building supercharger stations.
I think you just come back to spread slander again :(

All future Tesla EV's will have the Supercharger capability (standard or as an option), just like the Model S. The cost of the Supercharger capability will be priced in the price of the EV. There will be no per-use charge for charging at the Supercharger stations. That's what is unique about the Supercharger stations: free forever.

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