101–110 of 281 posts
> I do recall setting the cruise control to about 54 m.p.h., as I wrote. The log shows the car traveling about 60 m.p.h. for a nearly 100-mile stretch on the New Jersey Turnpike. 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 whee…
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 I were to speculate, and I am, I would guess that the variable here is the temperature of the battery packs. Batteries are chemical power sources, and the chemical reaction which frees up electrons has temperatures where it works, and temperatures where it doesn't. (Hence "cold weather amps" as a selling point on car batteries). Anyway, I'd speculate that the Tesla person was thinking that if the battery got up to…
> "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) that was later contradicted by other Tesla personnel." This is one of the more bizarre statements in this whole discussion. Why would anyone with the slightest understanding of electric cars or physics believe that to be true - and I mean the reporter, as…
To be fair, battery "conservation" is different than a battery "recharge".
> I do recall setting the cruise control to about 54 m.p.h., as I wrote. The log shows the car traveling about 60 m.p.h. for a nearly 100-mile stretch on the New Jersey Turnpike. 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 whee…
Maybe you aren't so hot either. Tell me, what do 19-inch and 21-inch specify? The outer diameter of the tire or the DIAMETER OF THE RIM?
So, grade school geometry refresher. When you increase the diameter of a circle, what happens to its circumference?
Thanks for playing: "Do I think I am clever but just accidentally revealed I'm the level of dolt that needs basic geometry spelled out and assumes everyone else is as clueless as me?"
If he had just driven the fucking car and recharged as necessary, from looking at the battery meter, it would've been a fine trip.
As the reporter noted, and Tesla itself has confirmed, the charging meter gets decalibrated in extremely cold weather (i.e., near or below freezing) and does not accurately state the charge level of the battery. In a nutshell, the decais the root cause of the scandal. Note that this problem is shared with all other EVs currently on the market (i.e., the Chevy Volt and Nissan Leaf). It's a basic problem of physics and…
In Elon's post, he states they have strong sales in nordic countries, we haven't seen any reports of failure from there. Just because they use the same underlying technology (Li-Ion) doesn't mean all battery packs are the same, Tesla's has a very different design.
Earlier quoted context omitted.
That seems to be plausible explanation, but I don't see how you give such advice to somebody on the road. You have two potential situations: 1. Battery has lost some charge for unknown reason, and has to be recharged. 2. Battery has proper charge, but the estimate is wrong. If you act according to true scenario, client is happy in both cases. If true scenario is 2 but you act like it's 1, the client wastes and hour t…
"If the support person gave different advice, he was setting himself and his company for the mess up, and the mess up ensued." This is why we need the call logs. And I fully suspect Tesla records them, so the fact that it wasn't released may suggest that Broder's account was indeed correct
If the Tesla people on the phone with the reporter had just erred on the side of caution with their advice, the whole debacle would have been avoided.
Broder complaining about a couple of extra hours charging would have just come across as a nitpick.
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…
Looking at the plots from Musk's blog post, the battery state of charge diminishes a bit overnight, but the estimated range diminishes much more. Presumably because a cold battery has a shorter range. As the battery warms up, the estimated range should go up as well. How much the range goes up probably depends on how much the battery warms up; in the cold morning weather in Norwich, the battery may have warmed up les…
As I understand it a given number of molecules' bonds can be broken at any point to generate current. In colder ambient temperature the propensity to generate current decreases. However, the quantity does not. In other words, the apparatus for measuring what "charge" is available will incorrectly judge how much is left, but an intelligent system on the other hand may also take into account what the ambient temperature is doing to the sensor of how much current flows given a certain test circuit.
I'd guess that there is not an objective way to measure the charge left. I'd also guess that at a colder temperature it might not have as much power or as much torque, but that it would not affect the range, especially if the battery if artificially (or intrinsically) warmed once it gets toward the "bottom" of its capacity.
What the support people could have been talking about is how to game the system so that the sensors report a more reasonable gauge of the true range. That means that the supposed decrease overnight was not that the potential energy dissipated, but that the colder temperature lead to less accurate readings. Causing a current draw through driving slowly in the parking lot and running the heater might cause the battery to heat up, and thereby affect the current available to a test circuit, something that matters to the sensors' test circuits.
I'd like to hear from someone who actually knows something about electrical engineering, but without being informed on the field, it looks like a failure of imagination in assuming good faith and imaging possible scenarios.
gratuitous analogy:
Let's say it is a fictitious 1975 where Porsche has remote telemetry, and a NYT reviewer is skeptical about oil-cooled engines, because he states that you may run a little low on oil then also be low on coolant or vice versa. In the early morning of a freezing day, he looks at the dipstick. It says he is a three or four quarts low! He calls support, and they tell him that he will have more oil if he warms up the engine, and he'll be able to go for a drive without hurting the engine. (They should have said that he would get a more accurate measurement rather than get more oil) So, he starts the car, revs the engine, drives in circles, etc. Maybe he checks the oil again, maybe not. He takes off, and a couple hours later the engine seizes up. Apparently, it was both looking like it was extremely low on oil and was also actually very low on oil. The telemetry shows the reviewer appearing foolish, and possibly trying to ruin the engine. You could say that he is a professional and should have been able to parse the statements from support more intelligently. Yet they both look bad, but it may not be an inaccurate depiction of what end users would experience.
From the article, "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 planner at the company’s headquarters in California." That quoted sentence includes the interesting phrase "Tesla's spokeswoman at the time," seemingly i…
Earlier quoted context omitted.
Sure it is. But that will only work when you warm up the pack, not when you warm up the car. The draining of energy will also warm up the pack (it should, to some extent because the pack will have an internal resistance which the current passes through, which will turn into heat) but this is still much less efficient than using that energy to propel the car forward. The band where draining at a lower rate would warm…
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.