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That Tesla Data: What It Says and What It Doesn’t

wheels.blogs.nytimes.com

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Re: That Tesla Data: What It Says and What It Doesn’t

#141

Post by lttlrck »

enraged_camel wrote: post #67
HelloMcFly wrote: post #44

Earlier quoted context omitted.

Good thing Musk is willing to "stand up to them" given that he's the truly unbiased one in this situation, right? He's playing an angle here too. And the other article ( http://www.theatlanticwire.com/technology/2013/02/elon-musks... ) casts some doubt on his loud protestations. And they've only released their summarized charts, not the raw log data, anyway. It's already a "he said / she said" situation, it's just th…

On the other hand, Brody has known record of exaggeration and distortion of truth. Whereas Musk is an honest, no-nonsense engineer. (Although I'd be interested if you could point me to a situation where Musk was caught blatantly lying about something.)

If that is that case, Musk would have known about his alleged "agenda" before handing over the keys for the review and could have acted accordingly. But he didn't.

Re: That Tesla Data: What It Says and What It Doesn’t

#142

Post by danielweber »

jacquesm wrote: post #59
danielweber wrote: post #51

Earlier quoted context omitted.

A car in motion uses ten times the power of a house. The engineers apparently wanted him to slowly pull power from the battery, which would be consistent with "sitting in the car with the heat on low." If it turns out Tesla denies telling him how he can condition the battery, that would be significant.

It would be interesting too to see the rates of power consumption for the model S at cruising speed and the 'heat on low'. From what I remember (doing some electric car design a long time ago) a car that is cruising at about 50 miles per hour uses > If it turns out Tesla denies telling him how he can condition the battery, that would be significant. It would be, and on top of that they could prove in a re-run that th…

A Tesla gets between 3.5 and 4.0 miles per kWh[1] at 55mph. That means in an hour they'll use 13.75 to 15.62 kWh.

[1] Doing math for range / capacity at http://www.teslamotors.com/models/options

Re: That Tesla Data: What It Says and What It Doesn’t

#143

Post by makomk »

ChuckMcM wrote: post #131
codex wrote: post #102

Earlier quoted context omitted.

The battery's heating system likely drained the power overnight. The battery pack must be kept above a certain temperature or it will become irreparably damaged.

Do you have a reference for that? I ask because while I can imagine there are limits the kinds of things I've not seen one for Tesla's battery packs. I see that typical LiOn type batteries have a 'one month at -20C (-4F)' sort of limit, car batteries are typically better than that, good to -40F or so. Edit: This article http://electronicdesign.com/power/operating-conditions-get-t... says "permanent damage at -50 degr…

Hah - someone in the first HN discussion about this was complaining that it was unfair to complain about the Model S becoming less efficient at low temperatures because ICE cars did too, and as I recall his definition of low temperatures was -50C.

Re: That Tesla Data: What It Says and What It Doesn’t

#144

Post by smsm42 »

brisance wrote: post #140
smsm42 wrote: post #99

Earlier quoted context omitted.

I think here the case is simple. Broder did not record his speed accurately, he just drove "around 45 mph", which very well might be actually 55 mph, on a good road with a good car 10 mph difference in speed doesn't feel at all. However, he can't just say "I didn't really collect the data accurately" since it'd hurt his credibility, so he mentions completely unrelated discrepancy in hope that most of the readers woul…

Or maybe he did report what the speedometer showed, and the calibration is off.

That is a possibility too. On a mass-produced car, I'd evaluate this as pretty low probability, since setting speedometer for the actual car specs is a basic expectation and if any company would let wrongly calibrated cars out of their factory it would be a huge liability issue and a very loud scandal. However, if custom modifications were made to the car, it is not out of the question, theoretically. But then the effect of the smaller tires should be the opposite, not? I.e. with smaller tires the speedometer should overestimate the speed, not underestimate?

Re: That Tesla Data: What It Says and What It Doesn’t

#145

Post by erichocean »

lawnchair_larry wrote: post #71
luigi wrote: post #7

Overall I think Broder acquits himself well, and his explanation about circling the Milford parking lot makes sense. Also, the Tesla engineer he was on the phone with at the time should have been able to tell Musk that happened (or Tesla should have just asked Broder to comment before posting the rebuttal). His action here is still hard to understand: > The Tesla personnel whom I consulted over the phone – Ms. Ra and…

That stuck out for me and I think he is being dishonest with his delicate wording. They didn't clear him to go, as he suggests. They told him that it would be ready in an hour. He also explains that he drove past a station "because no one made him aware of it". That smells like wordplay too. He was probably aware of it, and any reasonable owner of the car would probably be aware of it, or be well equipped to look it…

They didn't clear him to go, as he suggests. They told him that it would be ready in an hour.

This is exactly the point of contention, and presumably, there should be a call to Tesla after the hour of charging if Broder's version is correct, and not if Tesla's is.

We'll see.

Re: That Tesla Data: What It Says and What It Doesn’t

#146

Post by erichocean »

jacquesm wrote: post #30
zeteo wrote: post #16

The logged data does support the broad lines of Broder's story (large drop in battery charge overnight, slow driving, turning down heating) and the 10-15% imprecision (driving at 52 mph instead of 45, heating goes down at 200 miles instead of 182, charge time of 47 minutes instead of 58) is well to be expected from what is a journalistic review and not a scientific experiment. So this all comes down to what customer…

> So this all comes down to what customer service might or might have not said over the phone. Exactly, that is what I get out of it too. And that is probably conveniently unverifiable. Tesla really should repeat the trip with the same parameters as much as possible. Common sense dictates that if they waste power the way indicated that they should run out of juice and if they are conservative and follow the normal pr…

We don't need to know what was said, just that a call was made.

Broder claims that he was "cleared to drive" after an hour of charging with 32 miles of range on the car for a 61 mile trip.

But I don't think that actually happened (note how delicately Broder discusses this now). Tesla certainly denies it. And this is the reason the review was "bad", so this gets to the crux of the issue.

What at least happened, according to Broder, is that they told him to "plug it in for an hour, and then it should be good to go". Note the "should". Broder never actually says that he called Tesla back when the hour was up, explained there was only 32 miles of range left on a 61 mile trip, and that Tesla said "go for it, you are cleared for takeoff".

So Broder found his angle, thinking: I'll plug it in for an hour, then just leave, no matter what the range says. Hopefully it'll die on me this time. [Ed: I made up that last part, for flavor.]

Unfortunately, Broder wrote that Tesla "cleared him to leave", which doesn't seem to be the case, and according to Tesla, was not the case, and that's why he's in the hot water that he's in. If instead he simply quoted the reps and said he didn't call back, despite the data, he'd be in the clear (although the story would be far less compelling, since it'd be clear to everyone that Broder is either an idiot, or has an agenda -- or both).

Either way, all we need to do is see if Broder made a call to Tesla when the hour was up. His cell phone log is sufficient, and Tesla might have similar data on their side. We don't need to know what was said, we just need to confirm that Broder even had the opportunity to be "cleared" to drive by Tesla. Once we confirm that, then the tapes would be helpful. Otherwise, Tesla's version is the accurate one.

Re: That Tesla Data: What It Says and What It Doesn’t

#147

Post by shawn-butler »

jacquesm wrote: post #32
majormajor wrote: post #26

Earlier quoted context omitted.

"Mr. Straubel said Tesla did not store data on exact locations where their cars were driven because of privacy concerns, although Tesla seemed to know that I had driven six-tenths of a mile “in a tiny 100-space parking lot.” While Mr. Musk has accused me of doing this to drain the battery, I was in fact driving around the Milford service plaza on Interstate 95, in the dark, trying to find the unlighted and poorly mar…

There is a good chance that the vehicle stores that data for a limited time, not that it is posted through telemetry. If they are snooping on their cars (all of them, that is) then they have other problems. Fleet cars are also routinely fitted out with vehicle tracking systems, sometimes for insurance purposes.

The Congressional Budget Office has recommended a pilot program of mandating GPS tracking of electric vehicles in order to tax them per mile driven.

Since they don't consume fuel they don't pay fuel taxes and don't contribute to surface maintenance of roadways.

Re: That Tesla Data: What It Says and What It Doesn’t

#148

Post by ghaff »

hype7 wrote: post #65
codex wrote: post #38

The tit-for-tat details here don't matter. The story is simply, "The Tesla lost a ton of range overnight, unexpectedly. Tesla said it would come back after an hour of low-power charging." Is that true? Clearly the former statement is true but the latter is not. The only question is whether Tesla gave the reporter bad advice, or whether the reporter lied because he wanted to sabotage the test. Given Tesla's focus on t…

I agree with you that the tit-for-tat details don't matter; I don't agree with you that the only question is whether Tesla gave the reporter bad advice. This is a textbook example of how not to solve a PR problem — to get in a public, internet-driven slanging match with a journalist. Instead of "publicly refuting", Musk should have called up and got a full account of what went wrong; put the journalist on side, and g…

But Tesla is at least consistent in their approach, see e.g. battery "bricking." http://www.nytimes.com/2012/03/04/automobiles/Tesla-Battery-... (This is an NYT story although it wasn't originally reported there.)

I'm generally rooting for Tesla and EVs (where they make sense). But I didn't think much of their PR handling of a situation where they were at least somewhat in the wrong was good then and I don't think it's good now.

Re: That Tesla Data: What It Says and What It Doesn’t

#149

Post by enraged_camel »

lttlrck wrote: post #141
enraged_camel wrote: post #67

Earlier quoted context omitted.

On the other hand, Brody has known record of exaggeration and distortion of truth. Whereas Musk is an honest, no-nonsense engineer. (Although I'd be interested if you could point me to a situation where Musk was caught blatantly lying about something.)

If that is that case, Musk would have known about his alleged "agenda" before handing over the keys for the review and could have acted accordingly. But he didn't.

I don't think Musk has the time to do background checks on every media person who wants to test-drive a vehicle. And the supposedly credible reputation of NYTimes may also have led him to trust Broder. In his blog post however he admits that he made a mistake there.

Re: That Tesla Data: What It Says and What It Doesn’t

#150

Post by coffeemug »

kdsudac wrote: post #57

I get why Musk feels like he needs to defend his company but I think he may be doing more harm than good on the PR front. Do you think the average Tesla customer is going to want to wade through a bunch of plots of battery charge vs distance, etc? I think the takeaway for the average Tesla customer might be along the lines of "hmm, this seems really complicated.... am I going to have to keep the heat down while I dri…

To me, Musk comes across as an out-of-touch engineer who keeps trying to argue the technical case and insists it's the customer's fault.

I interpreted the blog post very differently. He says that the article is an outright premeditated lie, and presents an overwhelming amount of technical data to back up his claim.

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