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Comment by ansy | Hacker News Reader

Great looking car. But what's with all the bullshit vanity stats like kWh? Is this the new MHz of the electric car age? A meaningless number that consumers mistakenly use to quantify purchases for the next century? Some things never change. Just tell me how far the damn thing drives and I'll dig into the details if I'm really interested.

NB: I realize Tesla buries the actual range in the middle of the page. I'm just pointing out kWh at best meaningless without taking the entire car into consideration and at worst deliberately misleading consumers a la MHz and "megapixels."

What consumers understand: Range in miles, top speed in mph, acceleration (why don't they illustrate this with a graph instead of "0-60?"). What consumers can only vaguely understand: kWh, horsepower, CC of engine, torque.

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How is that meaningless? It's what determines a large portion of the price of the car and it's range. You don't think it's helpful to know that the Leaf has a 24 kwh battery and the low end Tesla has 40? I'd say the range "estimates" are the useless number. The range is 90% determined by the battery capacity. The range estimates are whatever number marketing pulls out of its ass. This is nothing like megapixels and megahertz.

Yes. It is meaningless to know the Leaf has a 24 kWh battery and the Tesla has 40 kWh. Completely and utterly useless.

Range is determined by engine, weight, aerodynamics, and, yes, battery. The Leaf could, hypothetically, weigh half as much as the Tesla Roadster S, have a better coefficient of friction, a smaller engine, and get BETTER range with a smaller battery.

It's like telling people how big the gas tank is on a car. There's a hell of a lot more you need to know to figure out the range. To give an extreme example, just because my passenger van has a 30 gallon tank and my civic has a 11 gallon tank doesn't mean the van is going to win an endurance race.

Edit: Another concrete example, the Volkswagen 1L. It has a 1.7 gallon gas tank and gets a 400 mile range. [1] Your average Toyota might have a 50 mile range on the same amount of gas.

[1] http://en.wikipedia.org/wiki/Volkswagen_1-litre_car

Yeah, but what if I'm buying a Tesla Model S... so all else is held equal? I don't understand how you don't see this as useful information when comparing options within a single line of vehicles.

Two important aspects that are covered by battery capacity but not range are cost to recharge and lower bound on time to recharge given a certain wiring capacity in your home.

So how many mA⋅h in your laptop's battery?

You know, I really like the idea of getting the real numbers for what I'd be paying for. kWh of the battery is a clearly definable number that makes it easy to compare between the different options. "How far the damn thing drives" is incredibly fuzzy and dependent on things like speed and driving habits - for a start, their estimate is at 55mph which seems slow to me to cover 300 miles at (is that the limit in the States or something?).

The 0-60 time is used widely across the automotive industry, as you probably know. I've not seen anyone use "a graph" before, but frankly I prefer this; those numbers tell me that they're all pretty quick (and the 4.4s one extremely so) and I can easily compare that to petrol alternatives.

> is that the limit in the States or something?

It depends.[1] Speed limits in the US are set by states rather than the Federal government, so they vary depending on where you happen to be driving. Larger/less-dense states tend to have higher limits than smaller/denser states do. There was a national speed limit of 55mph put in place on highways in 1974, but it was repealed in 1995.[2]

My guess is that they go with 55mph because memories of the national highway speed cap mean that figure is still fixed in lots of peoples' minds here as "highway speed."

[1] http://en.wikipedia.org/wiki/Speed_limits_in_the_United_Stat... [2] http://en.wikipedia.org/wiki/National_Maximum_Speed_Law

I imagine the range would be very hard to quantify exactly, since it would probably depend on many many variables, such as driving style, speed, road grade, ambient temp (battery efficiency), head winds etc. It's an electric car, with the dominating cost being the battery, I think it's a legit headline stat, and probably the dominant variable between the models, except for the performance model, which seems to have a beefier motor controller/inverter.

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