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Comment by Swizec | Hacker News Reader

To me, the most surprising part is: Holy fuck, Audi's have huge petrol tanks! I usually fill up my reasonably priced car in like a minute or so and it gets a range of some 700 kilometers on a ~40 liter gas tank.

5 minutes for a petrol stop? That's insane.

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Likewise, I get 700 miles (~1100km) from a 10 imperial gallon (45l) tank.

With that said, it's not sensible to compare a modern european small car with the average US car. Particularly the class of car that the Model S is competing with (which are typically expensive, have a high capacity and relatively inefficient engine, and luxury interior).

If filling up your tank takes 2 minutes (1 minute filling + 1 minute overhead), you can tank 350 miles per minute. The Tesla S gets 265 miles in 1.5 minutes, which is 175 miles per minute. So your car can be refilled twice as fast as the Tesla S when measured in miles. Furthermore, you need to recharge the Tesla more often.

At least, Elon is honest about it and says "this is about convincing the people that are skeptics". (And not about making a fair comparison.)

Most US drivers are not getting 700 miles from a 12 US gallon tank (58 US MPG). The average fuel economy of US cars is 24.6 MPG.

An Audi A6, in the US at least, gets 33 highway MPG and has a 19.8 gallon fuel tank.

And yes, of course you charge the Tesla more often. You charge it every night when you come home, and it's ready with a full charge the next morning. That's just a totally different usage pattern from only filling up when it gets low like you do with a gasoline powered car.

I'd bet that most Tesla drivers will never have to stop to recharge, mostly because they will use their Tesla around town, and will take long trips in another car or fly, because Tesla owners are wealthy.

EDIT: converted imperial gallons to US

Note that imperial gallons are substantially larger than the regular kind. A 10 imperial gallon tank holds 12 US gallons, and so 700 miles from a 10 imperial gallon tank is actually about 58MPG. Still very high, of course.

Nitpick: regular kind? That's quite… culture centric.

The only "regular" capacity unit that I know of comes from a deliberate attempt to normalize every units. Namely, the Litre from the metric system.

Smug Frenchman

It's not my fault that one of the units is just the name of the other unit with a modifier. It's not like "gallon" is shorthand for something longer and more formal.

Hint: when an Englishman walks into a pub, he doesn't order an 'imperial pint' of beer...

imperial gallon & US gallon?

Or maybe more interesting but historical "ale gallon" and "wine gallon".

> I'd bet that most Tesla drivers will never have to stop to recharge, mostly because they will use their Tesla around town, and will take long trips in another car or fly, because Tesla owners are wealthy.

That's probably true, but much of the recent marketing around battery swaps and transcontinental charging networks is aimed specifically at road trips. I suppose one would argue that they're working on this infrastructure now for the future when much more affordable EVs are available.

You have to also factor in how many swapping stations they have in each "Tesla center". Typical gas station has at least 8 pumps larger about 16. Although, there is only a handful of Teslas, so possibility of a lineup is low.

Not just that, most people will most likely just charge at home and use battery swaps as an absolute last resort or when they're on a long road trip. I'm sure the cost associated with a battery swap is not "cheap" (i.e. diffing your battery capacity versus the battery capacity of the new battery and multiplying that by the total cost of the new battery. You weren't thinking you can just roll into any 'ol battery depot and swap out your 5 year old Model S battery with a brand spankin' new one, right ;)?)

Seemed normal to me. I think my wife's BMW SUV thingie fits like 90 liters.

At 10 gallons per minute, that's still just 2 minutes pumping time. (23 gallons)

Edit: I checked again, he pumps for 2.5 minutes and gets exactly 23 gallons. So I guess the pump isn't as fast as Elon says on stage. But it still surprised me because, well, that's about twice as long as what I'm used to :)

Did you watch the video? Not all of the time at the gas station is spent pumping.

This is a ridiculous discussion.

It takes about 3-5 minutes to fill up a large-tank performance car, similar in features and trim to the Model S. It takes about 2-4 minutes to fill up a smaller car. It takes less than 2 minutes to "fill up" a Model S.

It takes about 10 minutes if you also use the restroom. Are we going to start factoring that into the comparison? If not, I'm out.

Well it does seem that most of the time saved when filling up the Model S comes from not having to get out of the car in the first place. And I guess the credit card gets used from within the car?

They have your serial number. I'm sure it's just billed directly to your card on file.

What's probably most relevant is that it would take roughly as long to half-fill the Audi as to replace the Tesla's battery. That's in many ways a fairer comparison, as the Model S has roughly half the driving range of an Audi, and (I think) most car gasoline fill-ups aren't from near-empty back to full.

The model he fills up looks to be an A8. The A8 fuel economy is around 15-18MPG. So 20 gallon tank only gets 350 mile range on it.

Ok. That's a very guzzly car then, though; even other Audis like the A5 seem to do a lot better than that, especially on the highway.

Tesla's competition, from the perspective of performance and price, is very guzzly cars.

But big $100,000 cars like this mid-range S-class Merc http://www.mbusa.com/mercedes/vehicles/model/class-S/model-S... seem to have 20+ gallon gas tanks (here's the S550's capacity http://autos.yahoo.com/mercedes-benz/s-class/2013/s550/speci... ) and the ability to manage about 25MPG on the highway. That would place them at 500+ miles from a single fill. (They'll do a lot worse with city driving though: the S550 should only give 350 miles. I think these MPG numbers are the EPA's.)

Aside from the top end A8s with upgraded engines, they get 18MPG city and 28MPG highway. Simply saying that the A8 gets 15-18MPG is deceptive. So, if we are talking range, an A8 will get upwards of 560 miles on a tank.

If you're comparing on performance alone, you better get the upgraded Audi to match the Model S...

Pumps vary dramatically in speed. My car has a 15.8 gallon tank, and it can easily take a couple of minutes to fill up (in Virginia).

Not to mention random pumps that you can never get to pump at full speed because they seem to fail to detect that the nozzle is in your tank's hole, or that click and stop every 3 seconds because the gas backs up because it doesn't flow down the tube fast enough.

As Musk points out, this is the fastest pump they could find in their area. Pumps vary tremendously in speed. Actually I'm curious about why the same pumps are sometimes fast, and sometimes very slow. Anybody know? Does tank level really matter that much?

Haha, well if Musk says so it must be true!

In the US, fuel pumps meant for regular sized cars (not trucks, boats, planes, etc) are limited to 10 gallons/minute. If that pump really was that fast, then it really was (among) the fastest legal pump(s) in the area.

http://www.epa.gov/otaq/regs/ld-hwy/evap/spitback.txt

I think it has to do with how much fuel is in the gas stations storage tanks. When the tanks get low they pump more slowly. I think it has to do with the pressure created by the weight of fuel pushing gas out of the bottom of the tank faster, there is more potential energy to push the gas faster in a full tank, mass x gravity x height equals potential energy.

Pssst, a BMW SUV is also a heavy luxury vehicle.

It also depends greatly on how many other people are using the other pumps at the station. A station where every pump is in use pumps considerably more slowly than one where you are the only one pumping.

Yes,I thought the same, I even looked up the specs for some of their models. I thought they were bullshiting me. And I think they did, that was not 10 gal per minute.

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