I'm impressed that car runs as good as it does. Maybe there's hope after oil! Go Elon!
Elon Musk's Data Doesn't Back Up His Claims of New York Times Fakery
251–260 of 262 posts
Re: Elon Musk's Data Doesn't Back Up His Claims of New York Times Fakery
#252This whole controversy has been a little depressing to read...not that the Tesla vs. NYT discussions here have been worse than on other forums, but just because it shows how technical minded people are as easily swayed by preconceptions and alliances as more ostensibly non-scientific minds. How many words have been expended in the other HN thread to allege that Broder -- after most have already established that he is…
I've read all the arguments on both sides, and while both have made good points, there is one that stands out. This reporter clearly barely made any attempt at recharging his empty vehicle in Norwich, and then attempted a drive well beyond the car's capabilities, then made the "running out of fuel" his headline. If he would have done this on gasoline, the result would have been the same, and I think that is getting l…
No, what's getting lost is that it takes an hour to fill up that fucking car. Thanks but no thanks; 10 minutes at a gas station is enough to make me want to chew my own arm off.
Re: Elon Musk's Data Doesn't Back Up His Claims of New York Times Fakery
#253Earlier quoted context omitted.
> If Tesla told me that regenerative braking would improve available range in this situation, I think I would take them for their word. Think about what you're saying. Thesis: periodically pressing on the brake pedal and allowing some of the car's energy to be captured by flywheel generation actually improves battery life and vehicle range compared to simply driving along at the same average speed. True or false? In…
I don't think I said that; I certainly did not intend to. Let me retry: the amount of energy you can get out of a battery will drop slowly, but we can ignore that. Because of the properties of the battery, the amount of energy you can get out in a form that can drive the car may be a lot lower (extreme example: 1W of power may not be enough to even drive the electronics that control the starting of the engine. If so,…
> If the car's manufacturer suggests multiple small recharge-charge cycles (using regenerative braking) to do that, why would I distrust them?
The answer is simple -- they're wrong. Regenerative braking cannot recover more energy than was lost in getting the car to its present velocity, so the advice to engage in stop-and-go driving emanates from someone who doesn't understand physics.
Phase 1: Acceleration -- energy is provided by the battery to the car's electric motors. The battery energy required is greater than or equal to the car's final velocity as shown in m * v^2 / 2 (http://en.wikipedia.org/wiki/Kinetic_energy).
Phase 2: Braking (deceleration) -- energy may be recovered from the act of braking and delivered to the battery. There are two choices -- either turn the car's energy into heat with brake pads, or turn some of it into electrical energy that flows back into the battery using a method called "regenerative braking".
Can the energy recovered by Phase 2 equal the energy expended in Phase 1? No, this is not possible -- because of the second law of thermodynamics, one cannot recover all the energy, there are inevitable losses.
Therefore (read carefully) stop-and-go driving is always less efficient than driving at a fixed speed. Always.
> I know almost nothing about the chemistry of the batteries, and even less about their control software.
I'm not addressing what you may or may not know, only what the facts are. And if someone at Tesla actually offered the advice to engage in stop-and-go driving in order to increase the car's range, someone needs to go back to school.
Re: Elon Musk's Data Doesn't Back Up His Claims of New York Times Fakery
#254Earlier quoted context omitted.
So, you're saying he's not anti-semitic? ("One of these things is not like the other...")
ya got me there. the only thing that matters in any debate is how it makes me feel about my tribal identity. I forgot that for a second.
Doesn't parse. What indication did you give about tribal identity did you give beforehand? Also, what does the irrational hatred of a dead, old rich man have to do with that?
Re: Elon Musk's Data Doesn't Back Up His Claims of New York Times Fakery
#255This article has confirmed crucial aspects of Broder's version with third parties, such as the truck driver who picked up the inert car (it doesn't matter if the battery still has 28% power if the parking brake won't turn off, iirc Priuses also refuse to discharge their batteries below a critical threshold), and used Google Maps to verify other issues (finding the Milford supercharger).
I haven't seen anyone attempt to verify actual speeds based on computing the area under the speed graph, but I suspect that this won't help Musk's case. 19/22 (ratio of the wheel size of the car driven and the wheel size specification) is actually the perfect ratio to explain the variation between recorded speeds and reported speeds. Perhaps one is based on GPS and another on wheel rotation.
The correct response to this story was: we need to improve our customer service, software, reporting of range (especially w.r.t. temperature) and messaging; customers need to better understand the tradeoffs of gas vs. electric cars, and not claiming a senior NY Times reporter will lie to generate some extra hits on a pretty minor story.
Re: Elon Musk's Data Doesn't Back Up His Claims of New York Times Fakery
#256This article has confirmed crucial aspects of Broder's version with third parties, such as the truck driver who picked up the inert car (it doesn't matter if the battery still has 28% power if the parking brake won't turn off, iirc Priuses also refuse to discharge their batteries below a critical threshold), and used Google Maps to verify other issues (finding the Milford supercharger). I haven't seen anyone attempt…
> I haven't seen anyone attempt to verify actual speeds based on computing the area under the speed graph ...
Area under the curve -- then that would be to establish average speeds, yes? I think the recorded road distances and travel times would be a simpler way to establish that.
> The correct response to this story was: we need to improve our customer service, software, reporting of range (especially w.r.t. temperature) and messaging ...
Yes, that would have been a nice alternative to what actually happened. My pet gripe about Tesla in this affair was their advice to Broder to engage in stop-and-go driving as though that would help the car's range (it can't do that, it can only hurt compared to driving at a steady speed).
Re: Elon Musk's Data Doesn't Back Up His Claims of New York Times Fakery
#257Earlier quoted context omitted.
If the data clearly shows that he never "limped along" at 45 MPH, there's really nothing in those two paragraphs I can believe.
Mr. Broder's reply in the other thread was "I cannot account for the discrepancy, nor for a later stretch in Connecticut where I recall driving about 45 m.p.h., but it may be the result of the car being delivered with 19-inch wheels and all-season tires, not the specified 21-inch wheels and summer tires." I dont know how it measures speed whether GPS or wheel rotation or both and if that would make a difference. Anyo…
Looking at the Tesla Model S website[0] both 19" and 21" wheels (not tires) are available. The 19" wheels have 245/45R19 tires and the 21" wheels have 245/35R21. Punching that in to a tire size calculator[1] shows the following:
Tire Size Comparison
Specification Sidewall Radius Diameter Circumference Revs/Mile Difference
245/45-19 4.3in 13.8in 27.7in 87.0in 729 0.0%
245/35-21 3.4in 13.9in 27.8in 87.2in 727 0.3%
Which is a 0.3% difference in total circumference. Which is not a significant source of discrepency.
[0] - http://www.teslamotors.com/models/specs [1] - http://www.miata.net/garage/tirecalc.html (I used the non-java form at the bottom of the page)
Re: Elon Musk's Data Doesn't Back Up His Claims of New York Times Fakery
#258This whole controversy has been a little depressing to read...not that the Tesla vs. NYT discussions here have been worse than on other forums, but just because it shows how technical minded people are as easily swayed by preconceptions and alliances as more ostensibly non-scientific minds. How many words have been expended in the other HN thread to allege that Broder -- after most have already established that he is…
You are misquoting the interview. Basically, he said "Tesla is not doing hybrids because we think that hybrids cannot be as efficient as pure electric or pure gasoline cars". He never said that hybrids are a dead end, just that he and his team think that they cannot be pushed to the same level of efficiency.
The lawnmower comment is out of context and the link you provide misquotes it as much as you do. Specifically, "And then when you have consumed your 40 miles, which is not going to happen every day, but maybe every third day, you are going to have an engine that is really underpowered. It's kind of like a lawnmower engine trying to power my sedan. So it's going to be running at very high RPM, it's going to be working really really hard..." (with some stuttering taken out).
You can in fact question a lot of what he said. The Chevy Volt does not have two drive trains. The engine does not power the wheels directly, but is connected a generator which powers the electric motor. The gas engine in a Chevy Volt spins at three very comfortable RPM levels, and I believe the highest is 4500 RPM or so. I think what he did is slyly switched the topic from the Volt to other plug-in hybrids like the Prius, where I can see some of these problems being an issue. In other words, you are right, he definitely is trying to downplay any competition. However, he did not say that the Volt is a lawmower.
I am also somewhat confused as to why a 40 mile powerpack needs to exert 5x the power of a 200 mile powerpack, though this may be my own lack of understanding.
Re: Elon Musk's Data Doesn't Back Up His Claims of New York Times Fakery
#259Earlier quoted context omitted.
> If Tesla told me that regenerative braking would improve available range in this situation, I think I would take them for their word. Think about what you're saying. Thesis: periodically pressing on the brake pedal and allowing some of the car's energy to be captured by flywheel generation actually improves battery life and vehicle range compared to simply driving along at the same average speed. True or false? In…
I don't think I said that; I certainly did not intend to. Let me retry: the amount of energy you can get out of a battery will drop slowly, but we can ignore that. Because of the properties of the battery, the amount of energy you can get out in a form that can drive the car may be a lot lower (extreme example: 1W of power may not be enough to even drive the electronics that control the starting of the engine. If so,…
I would have thought the problems with the notion that you could recharge your car by driving it funny to be obvious: that would make it into a perpetual motion machine. Such things do not exist, nor can they.
You lack knowledge of physics, not chemistry. The implications of entropy are what you do not seem to realize. These things are independent of the car's inner workings.
Re: Elon Musk's Data Doesn't Back Up His Claims of New York Times Fakery
#260Shit, this is disappointing. And I was hoping we could announce a villain in this story before the weekend -- and now you tell me that it is more complicated than that?
Now I have to go back to being upset about there being horse-meat in lasagna.