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

wheels.blogs.nytimes.com

181–190 of 281 posts

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

#181

I put a graph together showing all the points/counterpoints and here's what I'm left with. - not charging past 90% at the 1st station is defensible. Especially if Tesla warns it will shorten the battery's life. - It'd be better if Tesla's software took temperature into account when estimating mileage range. - Broder is being ridiculous about the cruise control and his speed estimates, and the temperature. He has part…

The "fundamental attribution error" refers to our tendency to overattribute others' behaviors to their dispositions, while reversing this tendency for ourselves.

From: http://lesswrong.com/lw/hz/correspondence_bias/

Also, this:

We tend to see far too direct a correspondence between others' actions and personalities. When we see someone else kick a vending machine for no visible reason, we assume they are "an angry person". But when you yourself kick the vending machine, it's because the bus was late, the train was early, your report is overdue, and now the damned vending machine has eaten your lunch money for the second day in a row. Surely, you think to yourself, anyone would kick the vending machine, in that situation.

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

#182

I put a graph together showing all the points/counterpoints and here's what I'm left with. - not charging past 90% at the 1st station is defensible. Especially if Tesla warns it will shorten the battery's life. - It'd be better if Tesla's software took temperature into account when estimating mileage range. - Broder is being ridiculous about the cruise control and his speed estimates, and the temperature. He has part…

Most of this analysis is spot on in my opinion - the one area I disagree with you in is the portion where he allegedly drove in circles. The graph Tesla shows is misleading and completely blown out of proportion. 0.6 miles is not very far to travel, especially when 0.2 miles are accounted for by the offramp. A drive once around an unfamiliar parking lot in the dark, looking for a small charging station can easily acc…

> 0.6 miles is not very far to travel, especially when 0.2 miles are accounted for by the offramp.

The graph seems to me to clearly account for the offramp. It doesn't start counting the 0.6 miles until his speed has slowed down to "I'm turning in now" conditions (0.1 mi after the origin point), and the graph itself tops off with the y-axis at 30mph—well below interstate offramp speeds—so at least some of the rest of the 0.2 mi long frontage is simply omitted off the left side of the graph.

I agree that this particular complaint is probably the weakest in Musk's post.

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

#183

Earlier quoted context omitted.

I assume it has to be enabled with physical access to the vehicle, though I don't know this for certain. If they can turn it on remotely, then yeah, that's definitely bad.

I am still unclear, were these diagnostics being sent to a tesla server somewhere or was this information hardlined post review? Source? Also, how is this bad anyway? Google probably has this information already, if not google, your phone's carrier definitely does.

The more people that track your movements, the more potential for security breaches or malicious use.

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

#185
A quote: "About three hours into the trip, I placed the first of about a dozen calls to Tesla personnel expressing concern about the car’s declining range and asking how to reach the Supercharger station in Milford, Conn. I was given battery-conservation advice at that time (turn off the cruise control; alternately slow down and speed up to take advantage of regenerative braking) ..."

This is unbelievable. The advice is quite wrong, what remains is to discover whether Broder actually got this advice from someone at Tesla or made it up (or misremembered it). If Tesla offered this advice, someone needs an education in electric car technology (stop-and-go driving can only hurt battery life compared to driving at a steady speed). If Broder made it up, it casts into doubt the remainder of his account.

For the record, regenerative braking is not something that one can take advantage of -- it's always less efficient than not losing the energy in the first place. It's only a way to minimize the energy loss involved in braking, it can't eliminate the loss.

As to cruise control, in level terrain, it can only help the car's range by preventing the driver from wastefully changing speeds.

"... that was later contradicted by other Tesla personnel."

Ah. Well, then. Tesla should have phone records, but probably didn't record what was said (in many places, recording phone conversations is illegal without explicit consent).

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

#187
post #79

Earlier quoted context omitted.

"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--it couldn't possibly be a faulty design, confusing U.I., or marketing not realizing a common (mis)use case. " Fully agree. This is a great case study for other startups on what not to do.

For some reason this story reminds me a lot of Steve Jobs and the response to the Antennagate fiasco.

There are profound differences, but let me focus on one:

Jobs and Apple tried to make the claim that people were holding the phone wrong, without ever making the claim about the proper way to hold the phone. They never said anything about the "right" or "wrong" way beforehand, so while the comment is strange it isn't hypocritical.

http://www.engadget.com/2010/06/24/apple-responds-over-iphon...

It's a very strange response, and clearly foolish, but Apple never made a claim before the launch that the phone could be held that way. And of course, we can be generous in retrospect because Apple eventually gave free bumper cases. But Jobs didn't make a claim on the website which was contradicted by the behavior.

In contrast, Tesla claimed that leaving the car out for a long time shouldn't cause much battery loss: "The Model S battery will not lose a significant amount of charge when parked for long periods of time. For example, Model S owners can park at the airport without plugging in."

http://www.teslamotors.com/models/facts

It strikes me odd because the claim, prima facie, suggests that you can leave the car for multiple days without charging. Musk is contradicting Tesla literature here, which is why you should always be careful about the marketing material.

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

#188

I put a graph together showing all the points/counterpoints and here's what I'm left with. - not charging past 90% at the 1st station is defensible. Especially if Tesla warns it will shorten the battery's life. - It'd be better if Tesla's software took temperature into account when estimating mileage range. - Broder is being ridiculous about the cruise control and his speed estimates, and the temperature. He has part…

Most of this analysis is spot on in my opinion - the one area I disagree with you in is the portion where he allegedly drove in circles. The graph Tesla shows is misleading and completely blown out of proportion. 0.6 miles is not very far to travel, especially when 0.2 miles are accounted for by the offramp. A drive once around an unfamiliar parking lot in the dark, looking for a small charging station can easily acc…

[deleted]

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

#189
I cringed when I read Musk's charge that he circled the parking lot, suggesting it was done out of a desire to kill the car that just wouldn't die on its own. Who among us hasn't circled a parking lot a few times? There are so many other possible reasons that making a charge like that, something that if true could forever tarnish a journalist's career, was inappropriate.

I don't blame Musk for his desire to reply and "clear his name." (I'd be surprised if he didn't identify personally with Tesla). But I think he let his inner-geek shine through too much. That post of there's was in the classic slashdot style of point-by-point refutation. You don't win friends that way.

Maybe a better strategy would've been to politely refute the conclusions about cold weather -- since when is this guy a batter scientist -- but then suggest that some bad luck and confusion had more to do with Broder's experience than the cold weather, and possibly invite somebody to spend a little longer with the car -- a week, a month -- to come to conclusions not as tainted by circumstance.

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

#190
post #3

Two bits are completely non-sensical to me, is there any battery technician or otherwise knowledgeable person that can indicate in what conditions this makes any sense? > Beginning early in the morning of my second day with the car, after the projected range had dropped precipitously while parked overnight, I spoke numerous times with Christina Ra, Tesla’s spokeswoman at the time, and Ted Merendino, a Tesla product p…

> If there is one thing that will use up large amounts of energy it is electric heating, I find it hard to believe that using a heater as a consumer would regenerate the battery capacity in excess of what the the heater is consuming unless most or all of the energy was directed at the batteries.

If temperatures are low and if the charging station can deliver more power than the batteries need to charge up, then using the heater may warm up the battery pack and allow it to charge more efficiently, then discharge more efficiently after leaving the station.

When batteries are cold, they neither charge nor discharge efficiently. Batteries benefit from higher temperatures (but not too high, as the recent Boeing Dreamliner battery story reveals).

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