Featured Tesla quality

Nissan's battery failures had nothing to do with state of charge. Thermal control is a whole other topic having nothing to do with what I said.

 

If you don't agree with my characterization of "cheating", you should at least admit it's not an apples-to-apples comparison. My friend has a Model 3 long range, and he charges every night at home, The car reports something like a 220-240 mile range when finished charging. That's because he follows the recommendation of only charging to 80% - like everyone else does, and because it's currently winter. And that range is approximately to zero. Sometimes you might have some reserve but I've seen others who saw their range drop from 20 miles to 0 and the car is stopped basically instantly. The range remaining is just an estimate because you can't directly measure the battery state of charge.

 

Yes.

True, but that has nothing to do with the maximum float voltage achieved during charging.

No, it doesn't.

Thermal control to extend battery life is a separate thing from charge control to extend battery life. I feel like that's so obvious that I shouldn't have to explain that they are different. You can have perfect thermal control and still over-charge the battery, and you can perfectly charge the battery and still ruin it with lousy thermal control. They're separate.

 

If I were designing an electric car, I'd do what Tesla did. I'd prefer it that way. But the fact that some other companies don't trust their customers to understand the downside of charging to 100% is entirely understandable in a world where most people don't understand anything technical at all, and aren't willing to learn.

I've read about people who owned Teslas, charged to 100% every day and then went to Tesla for a battery replacement under warranty, only to be told that they abused their batteries. This is the sort of thing that can happen when you trust users to make wise choices, even if you attempt to recommend wise choices and educate your users.

I'm just saying their range estimates are not really comparable with everyone else's range estimates just because they allow you to charge to 100% (and recommend against doing it).

 

I believe the context makes it obvious that's what I meant.

There's nothing natural about that. It's not intuitive to most people used the plugging their phones in and charging them to 100% every night. Other battery chemistries have different causes of failure and thus different methods of treatment. You have to know about this for this particular type of battery, and the vast majority don't know it.

I think the person I remember reading about was a Lyft driver, and was driving 300+ miles every day, and always charging at Supercharger stations.

There are multiple reasons I think the 100% charging estimate is highly misleading, not the least of which is that it's for "trips" yet most of the time on a trip you're going to be in a hurry to charge (since charging takes so long) and the taper-charge at the end means most people don't charge to 100% anyway unless they are at an over-night destination charger. Waiting an extra 30-45 minutes for those last 20% is not something most people will put up with at a supercharger station anyway, especially if they've already been there for a half hour getting to 80%.

 

Okay, I think I should take the time to teach you something about engineering and operations - edge cases are EVERYTHING.

I wrote a custom controller for a research wind turbine. The actual C-code that controls the turbine is 22 lines long. The other 4,000 lines of code in that program are there to handle edge cases. In addition to that, I engineered an entire separate piece of electronics to monitor the computer and the turbine in case those 4,000 lines of edge-case code fail to properly handle edge cases.

The 737MAX debacle is about an edge case - a case where a sensor failure causes a computer to mismanage automatic trim AND the pilots fail to recognize that problem and take over, despite being trained to do exactly that. That particular edge case is going to cost at least 10 billion dollars, kill several hundred people, cost thousands of people their jobs, and inconvenience several million more.

Speaking of aviation, pilots learning to fly can often solo in their first hour or two of flying. A friend of mine effectively soloed on his first flight. All the rest of the training, studying, and flying is about handling edge cases. It's often said that any idiot can fly a plane, but only skilled, trained experts can handle in-flight engine failures, control failures, sudden unexpected weather, and all the other edge cases that come up rarely.

Dismissing edge cases shows ignorance of the fact that almost all design is about those edge cases. Design for normal, day-to-day duty is easy. Dealing with extremes of vibration, temperature, humidity, loads, electrical surges, overloads, underloads, and all the rest of the edge cases is where engineering is put to the test.

 

They're still separate. Whether or not you smoke and whether or not you exercise affect longevity, but one has little to do with the other. You can be doing one, the other or both.