Battery Swap Shortsighted

Battery Swap Shortsighted

Am I the only one that thinks this battery swap thing is going to cost way too much money and only be possibly useful for the next few years?
They're going to sink all this money into swap stations and then in a few years when superchargers get down to ~5 minutes for a mostly full charge, they're going to be totally useless holes in the ground.This must just be a marketing thing.

danielccc | June 21, 2013

"just" a marketing thing?

Marketing is important. Try to sell cars without marketing.

This is part of relentlessly removing any and all arguments against electric cars.

Docrob | June 21, 2013

100 swap stations spread around the country would cost $50 million spread over at least 4 years. GM spent 3 billions on marketing last year alone, even if this was purely marketing it would be cheap. Apart from straight swaps this also future proofs cars by allowing battery upgrades to 85 today and potentially far higher in the future. Considering the "a fill up takes longer then gas" is one of the last humps to EV acceptance the marketing potential of having these stations is ENORMOUS.

markjanharte | June 21, 2013

Yes, I think you *are* the only that thinks the battery swap is shortsighted.

wcalvin | June 21, 2013

While I too think that most will prefer "free" over "fast" at the Supercharger Corral, I think that this development will result in mass orders of the Model X from fleets, such as taxi companies and municipalities which run a car all around three shifts a day. Without such battery-swap stations, they might be reluctant to switch over to eCars.

The Model S isn't quite as suitable for fleets, except as executive cars or rentals. Though we might see some Model S as unmarked cars for speed traps....

Docrob | June 21, 2013

They should license the swap stations to fleet owners. Imagine a NYC taxi fleet with in house battery swapping, the running savings could be staggering.

Mark Z | June 21, 2013

Let's not forget one major economic benefit of swapping. Cost. Let me explain.

If I charge to 90% at home and drive 100 to 150 miles a day, the 85 kW battery pack is being treated well.

On a vacation, I might charge to 100% and run the pack down to near zero. I rather use the Tesla Station pack.

My original pack will last longer if I swap during the cross country trips. That saves money.

Docrob | June 21, 2013

Tesla can significantly reduce their costs of supplying these packs even if they are used heavily by selling them for stationary storage use once their utility as EV batteries becomes impaired. The hire costs then only needs to cover the difference between the buy and sell costs of the packs and the costs associated with building and maintaining the stations.

brijam | June 21, 2013

I'll be paying for swaps on my future road trips.

I own a P85. I love this news.

kristian.skogstroem | June 21, 2013

I was a bit disappointed since I had expected a battery leasing/rent option along with the battery swapping announcement.

By paying an monthly fee you could have a guaranteed battery capacity of say >75% and be able to use the swap stations. The packs in the stations would have a capacity of >75%. The downside is that your pack will have from 75-100% capacity. This, I think, would be acceptable for most people and when the battery capacity goes up to 120 kWh and above this will not be an issue.

I guess Tesla might put in some restrictions on range-mode charging for these owners to have more control of the degradation on the circulating packs.

The packs with <75% could be used in the grid, in supercharger stations etc.

I hope Tesla would implement this. That would make it really convenient.

rmp123 | June 21, 2013

Elon stated that if there is was demand for swapping, it would be rolled out nationally. They are going to test market first in CA. They they may roll out nationally. Having that option is a good thing.

justineet | June 21, 2013

@kristian.skogstroem....the battery leasing option may be pretty good idea for city dwellers who live in condos/apartments that do not have a convenient way to charge their Teslas. Instead of charging the batteries their cars they get it done at the battery swap whenever they are low on charge........

HenryT2 | June 21, 2013

I don't think he specifically said that ALL Tesla stations will have battery swap capabilities. I think that would be an unwise investment. However for heavily trafficked locations (such Barstow) this might be utilized at a rate that justifies its cost.

In any case, as others have mentioned, the cost of doing 20 of these is still worth it for the marketing benefits and as a foil to the time factor argument. When someone says "yes, but it takes so much time...", this will be the answer. Of course, they could say "but it's only available in such and such locations". But then, you'd say "in those other locations, I'll wait the 20 min. and get it for free."

As a "marketing gimmick", it's worth hundreds of millions.

justineet | June 21, 2013


@kristian.skogstroem....the battery leasing option may be pretty good idea for city dwellers who live in condos/apartments that do not have a convenient way to charge their Teslas. Instead of charging their cars themselves, they get it done at a battery swap station whenever they run low of charge........

justineet | June 21, 2013

EDIT :))))

bsimoes | June 21, 2013

Personally, I would have preferred that they sink the money into more supercharger stations....

RonaldA | June 21, 2013

If the battery swap is effecient and quick they could take advantage of partnering with Delta Sonic or Sheets stations saving the cost of full out new infrastructure. Also consider the cost of the car if you don't have to buy or worry about replacing the battery. Like Blue Rhino the battery belongs to Tesla. You own the energy. Upgrades are simple, one battery size is used, recycling is automatic. I say this is the way forward. Ask yourself, almost every other battery operated device you have except a cell phone has a changeable battery. No need for innovation here just building out or contracting with trained battery swap stations.

rd2 | June 21, 2013

I agree that this is a wonderful advance for EVs and will be used by long-distance travelers who don't want to wait, even 20min, to get recharged. It's great to have the choice. I have a P85 and I'm very happy they've introduced this option/technology.

That being said, I fully expect the stock price to drop significantly this (Friday) morning. $500k per station is a hefty increase in the SC costs. Earnings per share will take a major hit as a result, since adoption of this option will be slow. Bracing for a hopefully temporary dip here.

justineet | June 21, 2013

@rd2...stock price won't drop because Elon was careful to say the swap stations will be rolled out based on demand..........

nwdiver93 | June 21, 2013

" ~5 minutes for a mostly full charge"

Ever heard of I^2 R losses?... not physically possible. To send even only 40 kWh into a 400v battery in 5 minutes is ~6000 amps... unless the model S was designed with superconducting battery cables that won't happen.

TFMethane | June 21, 2013

@nicknike What production car have you ever driven that has a 700 mile range on a single tank? The Prius and my old civic hybrid have about 400 mile range, and that is considered very good.

If you think you're ever going to find a luxury car that goes 700 miles on a tank, you're a customer that will never be satisfied.

In fact, based on this thread, I think Tesla will beat ICE's on range in the relatively near future.

TI Sailor | June 21, 2013

Elon did the supercharger station announcement prior to the swap demo to cement the fact there will be a complete (and free) nationwide SC network, and he said more stalls and/or stations will be added as usage/demand indicates.

One day in the future, if TM's battery management technology is successful in practically eliminating degradation concerns, superchargers may seem outdated, with swapping being the primary "recharge" method on trips.

TFMethane | June 21, 2013


It's been a while since my engineering undergrad/grad days, so correct me if I'm wrong:

On a recent experience with the Barstow supercharger (nominally 90 kW) I got about 40 kWh in the battery in 30 min. That's operating at 355V and 182 Amps (64.6 kW actual - I just checked the photo I took at the time to confirm).

To do it in 1/2 the time (15 min), you would have to double the current to 360 Amps. This would increase the I^2 R heating loss by a factor of four.

to do it in 7 min (or about 1/4 of the time), you need 4x the current, or 720 Amps, and it would result in 16x the heating and loss with the same cables. If you made the cables twice as thick, though, you would reduce the resistance "R" by 2^4, or 16x - mostly compensating for the additional I^2R resistive heating problems.

Or to come at it differently, to put 40 kWh in the battery in 1hr means you need to supply 40 kW. 30 min would require 80kW (this is the nominal range of the 1st gen superchargers). 15 min would need 160 kW, and 7 min would need 320kW. 320,000W/400V = 800 Amps. I'm not sure where you got 6000 Amps from. I think your calcs might have been similar, but off by a factor of 10.

Sorry if my memory of electrical engineering is wrong. I'm a doctor now, and I haven't even thought about engineering since 2002.

TFMethane | June 21, 2013

The point of that whole post being that I don't disagree with the thread's primary point that it is technically feasible to supercharge at a speed that will incrementally and margnially reduce the appeal of battery swapping as time goes on.

The flip side of that, though: As battery capacities increase, the time to supercharge larger batteries increases, making swaps marginally more attractive than supercharging.

RationalOptimist | June 21, 2013

One way to look at this is solving the problem not of range anxiety, but of wait anxiety. As more Teslas hit the roads, the risk of showing up at a SC station and finding 5 cars waiting ahead of you will deter many from travel. Knowing that if worst comes to worst you can pay to swap will ease that anxiety considerably.

But there's another key point - and the math here is surprising. If there's just a 25% excess of dema nd over capacity for SC, a line will build that could easily, over a few hours, extend to an hour plus wait before you can even plug in. But if just one in four Tesla owners have the mentality that if they can't supercharge right away then they will pay for the swap, that eliminates the excess demand problem, and the lines will never build up as long. So every Tesla owner benefits from this, even if they never use the swap.

HenryT2 | June 21, 2013


Absolutely correct. I'm not sure why people seem to be having difficulty grasping the concept of long wait times. There are approx. 10K Teslas on the road today. There will likely be 60 to 80,000 on the road within 3 years and possibly several hundred thousand a few years after that. The more popular stations MAY scale up to double or triple capacity over the next few years. But Tesla's primary ambition is increasing coverage rather than usage of any particular station. There WILL be congestion at some of the more popular charge points. And the naysayers will change their tunes when faced with long waits to get at the chargers.

I do not have the supercharging facility turned on on my car. The primary reason was that I did not think it was worth the risk of taking my car on a long trip with my two young children and risk being stuck in the middle of nowhere for an hour or two waiting to access a charger. I may have to reevaluate with the battery swap option. As you said, even if I never use it, the fact that the option is there makes the supercharging option more valuable.

elirondon | June 21, 2013

Does anybody knows how much it will cost to swap the battery?
A fair price should be essential for this to work.

bob | June 21, 2013

Nice Marketing idea to appease the newbies and of course it is cool tech. However I would rather see the funds used to expand the Supercharger Network and/or accelerate Gen 3 rollout. Battery improvements over the next 5-7 years will make this concept redundant.
Max Bob

Carefree | June 21, 2013

The cost according to ELon will be 10 gallons of gas equivalent in your market segment. It could mean that swapping the battery in CA is more expensive than in other states where gas prices are lower?

susanv | June 21, 2013

The email that I got from Tesla when the battery swap demo video was up said, "Model S battery pack sawp happens in less than half the time it takes to fill a gas tank. Costs the same." This leads me to believe it will be in the $50-$75 range.

Tom A | June 21, 2013

Expecting that the rate of supercharging is going to get down to about 5min any time soon (if ever) is a bigger gamble than the swapping. The cells can only take so much juice.

A different chemistry or architecture will be needed, which is a complete redesign that would be at least 7 to 10 years down the road (which is a generous assumption on my part, at least to those of us not working in the relevant battery tech areas), and Tesla seems to be sticking to thei tried-and-true safety, efficiency and cost-effectiveness of their custom Panasonic 18650 Li-ion cells.

Tom A | June 21, 2013

I don't know how the swapping is going to affect the battery replacement program, particularly since you can keep swapping for a newer battery.

Of course, it sounds like it is the luck of the draw, whether you get a newer pack or not (I doubt you can order what pack you want ahead of time). And, it would depend on what that fee is for the difference between your older pack and the newer one you swapped, once you choose to keep it.

I haven't found anything yet that addresses pack capacities. Will these swapping stations have inventories of 60s and 85s, or are they more interchangeable that some (at least me) thought?

cb17 | June 21, 2013

Wow, lot of responses.

Marketing? As an announcement? Sure. First station? Maybe. But Tesla doesn't have GM's marketing budget as someone referenced. And even if they did, that doesn't mean we want them blowing money on a potentially outdated (or soon-to-be-outdated) form of "recharging".

I appreciate the actual technical responses to the potential physical limitations of super-fast charging, especially TFMethane with the only real rebuttal to the main theory. Although, I'd argue 2 things. Even when batteries get bigger, if charging got fast enough to charge the current batteries (near-gas tank size) in 5 minutes (hypothetically), that would still give EVs the same level of convenience as ICEs which is what the whole demo was about. I can't address the technical limitations of charging (heat lost, etc.), but Tesla claims they'll continue to be able to speed up charging so we'll see.

And a (granted hypothetical) 5 or even 10 minute full charge would not make it the charging experience significantly different than a gas station, so I disagree with Chris' line scenario.

The bottom line is that 500k per station is a lot to blow (and a big gamble) on something that may be irrelevant in the relatively near future. And it looks like even Elon agrees with me, so why the distraction?

cb17 | June 21, 2013

Ugh, I guess using here is wrong. I was trying to link to this at the end of the previous post:

Elon seems to be on the same page (see end of post)

TFMethane | June 21, 2013

Shucks, CB... I'm blushing.

jchangyy | June 21, 2013

This will all be "useless" arguments in 5-10 years down the line. why you ask? I think the next "generation" (not Gen III) of electric cars will have ultra-high capacity battery PAIRED with ultra-high capacitor.

You just charge the capacitor on your long distance trip (2-3 minute charge) and as you drive, the capacitor will continue to charge the battery for a distance of 4-500 miles. (currently, we can use our iPhones while it's being charged)

Now, Elon just needs to work that pairing the 2 techs together. Then, no need to swap batteries, or the infrastructure, etc to deal with. just need the supercharger stations.

TFMethane | June 21, 2013

@jchangyy. Supercapacitors are a pretty good primary solution and an adjunct. However, you run into the same technical problems for 2-3 minute charging as you find in my earlier post higher in this thread. You start to get to a level where the supercharger infrastructure becomes prohibitively expensive to deliver electricity at such high currents. You start to draw so much power that you need a 10K volt grid substation on site to supply the potential peak loads.

There is a limit using the current power grid to how fast you can charge and how many vehicles you can do at once. I'm not sure where it is, but I would imaging charging 6 supercaps with 60-85kWh capacity simultaneously in 2 min each would be coming close. not to mention that the cables would start to get so heavy that only a bodybuilder or a robot would be able to pick it up and plug it into the car.

All I'm saying is that you can't just extrapolate these trends to whatever goal numbers you want for charge time and capacity. There are real world costraints, and cost functions are not linear... they're more exponential.

TFMethane | June 21, 2013

Sorry for all the spelling errors and runon sentences. I've been up all night, and it's time for bed.

jchangyy | June 21, 2013

that's why i said in 5-10 years--hopefully and during that time period, we could solve all the logistical problems of think cables, requiring higher amp/voltage, etc. Just hoping.

Bubba2000 | June 21, 2013

With limited engineering and capital resources, Tesla needs to focus on decisive aspects of the business. Only 2% of trips are usually out of town. Of those, only a small portion need any kind of charging. Starting with a full charge of 85KW-hr good for 200 miles, I want to take a break while I charge the car... have a drink and a snack.

The most important aspects for mass adoption of the Model S, X are:
1. Supercharger deployment nationwide, 100 mile apart like they planned. Sooner than later.
2. Invest capital in automation, supply chain to reduce prices of the autos.
3. Hi end cars should have a battery good for 500 miles. How is that for marketing buzz?

With efficient production, Model S/X should be priced at 60k for the 85KW-hr base model. Then take it all the way to $120k for something with 500 mile range, hi performance, AWD, all pimped up. With a larger battery, charging is even faster... not that anybody would need it. Anything longer than that, rent a Winnebago!

cb17 | June 21, 2013


Ding ding ding. We have a winner.

vboring | June 21, 2013

You're all missing the point.

I created a new thread: Swap is Game Changer. I won't bury my comments here.

Nobody seems to realize it yet, but Tesla won last night. Based on the nonsense Elon talked about, I'm not sure if he realizes what he's done.

Haeze | June 21, 2013

@TFMethane as battery pack capacities increase, it could actually DECREASE the time it takes to charge.

Charging a battery from 15% to 80% is actually a VERY quick process, it is the last 20% that you must slow down and strongly monitor the cells to be sure you don't over-charge them.

As battery pack sizes increase, yes, the charge time from 0 to full will be longer, but the charge time PER-MILE decreases, since you no longer have to top off every cell. Charging to 80% on a 120KWh pack would get you about the same mileage as charging to full on an 85KWh pack, but take MUCH less time.

For those who are hung up on the cables at the SuperCharger not being thick enough, I am sure with the same idea of driving up on a pad, they could cheaply develop a SuperCharger stall that you drive into, and a 00 gauge cable is raised from the ground and plugs into a special port directly in the new battery pack. No need to worry about the cable being unwieldy, or about the cabling in the car not supporting the current. The only concern at that point is supplying enough juice from the grid, or from the solar panel's battery storage to support that much current draw.

Vic M | June 21, 2013

I agree with the original thread that this seems a distraction for Tesla, and not the best use of time or money. I own a Model S Sig, and am very happy with the supercharges. With battery swap, I could change the battery in 90 seconds, and then go to Starbucks for 10 minutes so my wife could go to the bathroom. What use is that? On long trips, we were always at service stations longer than the actual refill times.

Really, I only see this as useful when packs are in the 200 kW-hr range and cannot be fully recharged over night. In that case, you could drive all day and then swapping would save a lot of time. As-is, supercharging is really good enough and I will choose free over faster than I need.

up north | June 21, 2013

I like to travel about 450 miles a day in 150 mile stretches, it takes about 2 hours to go 150 miles and avoiding rush hours in metro areas about 2 hours and 30 mins.75 mph. I stop whether I need gas or not for about 20 mins. so it usually takes me 7 hours 30 mins. including lunch to get from motel to motel. in a tesla, charging at the super chargers at the 150 and 300 mile marks and pluging in at the motel or hotel at night you come up with the same time 7 hours and 30 mins. a comfortable safe in joyable day. and now the 65.00 you saved on gas can go towards the motel bill. for my self the battery swap would not save me any time or money.

carlk | June 21, 2013

People with negative view did not see the true meaning of the battery swap. It's not just for the 0.01% of situations someone might want a fast recharge on a long trip. It takes the battery anxiety COMPLETELY out of people's (potential buyer's) mind forever. The worst case that could happen to your battery, whether it's a low charge or failed old battery that need to be replaced, is you need to spend 90 sec at a station to get it replaced.

cb17 | June 21, 2013


I bet that number of people is 0.01% of your 0.01% that want the fast recharge.

Yes people are worried about the cost of having to replace the battery, but no one is freaking out about the battery dying half way down the interstate. At least no more so than the engine overheating or transmission dying in their ICE

carlk | June 21, 2013

@cb17 You failed to see this implementation might not be an important step for early adapters who are willing to take some risks and inconveniences but it's very important to change the perception of non-believers which still represent the majority of potential future Tesla customer. Like I said now the battery anxiety is completely taken out of the equation Tesla can go on to sell more cars on the true merit of the EV. Not to mention it also builds a barrier of entry for competitors that do not have this infrastructure. This is a super-brilliant move by Elon you better believe it.

lbjack | June 21, 2013

I, too, agree with cb17. I'm not a truck driver, and the notion that after driving for over three hours -- even in a Tesla -- one would't welcome a twenty-minute break is ridiculous. A 90-second swap for the price of a tank of gas? Even more ridiculous! Someone has made the point that swaps would be good for urbanites who can't have a home charger. Even if swapping stations were located in urban areas -- which Superchargers are not, for good reason -- would the urbanite be willing to pay the same for an EV "fill-up" as he would for an ICE car fill-up? I think not.

I'm with Bubba on priorities.

Right now, I'm personally disappointed that Tesla located a Supercharger in Barstow instead of Baker, thus making the popular LA-to-Vegas milk run problematic. For the Southern California Tesla demographic, a road trip means not only a trip up north (preferably along the coast) but a run to Vegas or a weekend in Palm Springs. I see another Supercharger in the pipeline for Stateline and another on the way to PS. That's a good thing.

This may seem beside the point, but it illustrates why I believe Elon is wrong to say he's taken out the last argument against the Tesla with the battery swap. The last argument is the absence of a built-out Supercharger network. As Bubba says, this needs to be fixed sooner rather than later. Battery swapping is just a side show.

PapaSmurf | June 21, 2013

Every Tesla owner recharges at home, right? So for the most part we start every day with a full tank of electrons.

I don't know about you guys, but the number of times I would even use a Supercharger is fairly low. 3 or 4 times per year maybe when I am driving on a long distance trip. And honestly, after 2-3 hours of driving, I could use a 20-30 minute break to use the bathroom, etc.

I cannot think of any likely scenario where I am going to be willing to pay $160 (cause you have to come back to get the battery also) just to be on the highway again in 90 seconds.

I am sure there will be some people that use this service. But my gut instinct is that the free Supercharger is going to be my choice for the few times per year that I drive 200+ miles.

cb17 | June 21, 2013

@carlk Range anxiety only exists because of cars like the Leaf which promote the perception that you can't go very far on an EV and also they're expensive. Tesla will fix that in Gen 3.

99% of the problem with sales of alternative fuel vehicles is cost. Most people don't want to spend more than $20-25k on a car. And most reviews tell them that you can't make up the cost in gas savings. I promise you, it's really just that simple. It all comes down to people just want the cheapest crap. Which is why this is even more of a bad idea, because there could now be this perception that in order to "refuel" your Tesla, you are locked into Tesla's ecosystem of chargers and swappers that cost the same as a tank of gas. If it costs the same as gas, why buy a $30k Tesla?

People don't care about the environmental argument (unfortunately).