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@Compton The shown graph is missleading, because it doesn't contain data up to now. If you add data of vehicles experiencing the Battery Gate you see a considerable jump down. Additionally they can only charge at SuCs at half the speed of new cars. And if you analyse the above graph you see...

NMC of Audi/Porsche has a much better lifetime and fast charging ability than NCA. This is also the reason why Tesla uses NMC for energy storage and not NCA, which is dead after about 500 full cyles or 1200-1400 typical charge cycles, that EM mentioned in the investor call after indroduction of...

On the other side the Taycan has at 150 km/h a similar range as the Model 3 LR RWD. There is still a large difference between EPA and reality. Charging Speed of Taycan is also much better. Here in there is a considerable drop of charging speed during winter, not only because of charge...

IMHO the changes Tesla has made are all connected to the same problem - lithium plating and the consequence - growing of dendrites. First of all, lithium plating is caused by lithium ions, that cannot intercalate into the crystal lattice of the graphite anode fast enough. Intercalation rate is...

Regen is limited to a value so that no cell surpasses 4.20 V.

Actually partly it does, because if one cell has lower capacity or higher IR than others the brick voltage will rise faster at charging and reach the termination voltage earlier, and will also fall faster and cause shutdown earlier. Balancing doesn't help much here, because cells are balanced...

The focus is not only on range, it is also on charging speed, which also has been reduced considerably. Both together have resulted in acceptable travel time before the firmware change.

Another sudden fire in Germany.

Running the coolant pump for a short time is probably the only possibility to measure current temperature of the cells. The temperature sensors are sitting at the inlet and the outlet of the cooling loop of each battery module. You can see the values with ScanMyTesla or TM-Spy.

This seems to be a good analogy. You can even extent this to the following: Imagine that the fuel tank of an ICE is punctured at the top end, and when the tank is filled to 100 % some fuel is sipping out, and causes fire danger. Instead of fixing the fuel tank or replacing it all together, the...

Static voltage is irrelevant when charging and stopping charging at a specific voltage.

The following image shows NCA cell voltage on low-current charging: Source So 4,1 V during charging means approximately 90 % SOC.

This is far from enough to warm the battery to best superchargering temperature around 100 F.

The question is whether this is caused by positive effect on dendrite growth, or because most user of superchargers charge only to a lower SOC and the battery is immediately after charging. Tesloop had supercharged its first Tesla always to 100 % and got a battery replacement at 200,000 miles.

It is very easy for the BMS to keep the voltage below a specific value in batteries with multiple cells in series. Actually, it is the main purpose of the BMS to keep voltage of all series cells within a specific voltage range. Lithium plating happens also on much lower voltage than 4.2 V...

There are two main degradation modes: - lithium plating caused by cycling - electrolyte degradation caused by calendar aging Both have different parameters that cause degradation. I.e. low temperature is bad for cycling, but good for calendar aging.

Yes, of course! Tesla has all right to define what available capacity corresponds to the 100 % mark shown to the driver. They define what is save, because the have to cover the risk of sudden battery fires. I am sure that you would be also one of the first who would Tesla sue when your car...

Yes, this capacity still exist, but it is not save to use it, just like the capacity that can be gained from a cell charged to 4.25 V or even 4.30 V. That is about 3-5 % additional capacity that isn't used, because degradation will accelerate and the risk of thermal runaway on cell temperatures...

Probably every BMS in a notebook BMS is taking away capacity from lithium battery constantly, at least my Dell notebooks are doing this since more than 10 years. You can read out current capacity with tools like HWINFO. Dell is doing this even more than 99 % of the time the notebook is...

The point is that the problem certainly developed over time, but became visible to the users instantaneous after new firmware has been installed, which was able to detect the problem. If the sudden drop would have been expected by Tesla, I am sure they would have found a way to decrease the kWh...

I found an interesting paper about detection of nascent internal shorts caused by dendrites. Of course, a dendrite perforating the separator will not always cause a thermal runaway. If it isn't severe enough it may just cause higher self-discharge, or it is burned away by high current and just...

What is natural normal degradation? The value seen in the display is an artificially calculated value by the Tesla BMS. Taking operational safety into account the calculation was just wrong so far and this has been fixed now.

What are are thousands of battery cells charged in mostly favorite conditions against billions of battery cells charged at to high rate for battery temperature? How often did you charge your cells at 50 F and below at 0.5C and much below? I am sure that your "smart chargers" are far from being...

This is the key statement! To protect the battery means nothing other to make and keep the battery save. It has nothing to do with better estimation of range, but only with preventing excessive lithium plating in the future. Of course, the side effect is the increasing lifetime.

I don't agree here, because every buyer knew that there will be battery degradation. Tesla didn't know in advance how large real degradation including keeping battery safe, will be in the future. Up to now their capacity calculation did only capacity degradation take into account that appears...

Result of the "damage" is a battery fire. If there is no battery fire then there is no "damage". If you read Peter Keil's dissertation you will see that lithium plating is the normal cause of battery degradation. The problem is excessive lithium plating causing damage by growing dendrites...

If they had known that the situation causes batteries to take fire on parked cars in the future, I am sure that they would have taken immediate action. But it looks like they have seen something coming, probably not the fire risk, but fast degradation of some batteries, and have taken some...

It is an educated guess by combining information about the reason why lithium batteries start burning when car is parked, and the fact that not all cars have the same loss or even no loss.

It is not your fault! Probably it is Teslas fault, because they didn't give good advise. They always said that the BMS will handle all this, and a lot of Tesla Fans jumped in and spread this word. But Tesla may not have known this up to 2 years ago, because this issue developed over time and...

IMHO. if you are concerned on safety you should install the updates. The new algorithms limiting the charge voltage certainly reduces the risk of battery fires. Off course, it comes with the negative side effect of loosing battery capacity. We have to see how that can be compensated by Tesla.

One know fact regarding charging lithium batteries is that they must not be charged below 32 F. But this isn't a physical constant, more a rule of thumb. In reality it is a combination of temperature and charge rate that has to be adhered to prevent lithium plating. The charger rate has to be...

Yes, you can charge lithium cells always to 4.2 V, but this doesn't mean that this is without risk. You normally don't see if it is still save to do so. Tesla now uses an algorithm to detect abnormal state in individual packs and stops charging at lower voltage. The voltage is different for...

The BMS is warming the cells before charging. But the parameters set are not optimal, especially when supercharging. There are several studies that show that charging at 50 F ist bad for cycle life. Over the last few years Tesla constantly improved the parameters by increasing temperature more...

Sorry correction: - Driving and Charging in Winter with range mode off!

Charging was like I described above: - Daily charging was only to 60 % - SOC was more than 95 % of time below 50 % - Driving and Charging in Winter with range mode on - Charging in Winter when battery was still warm from driving. - Charging to 100 % a few times per year

Current values: Old Values:

Degradation visible in the crowd sourced data took only account the range calculated from the calculated full range by the BMS at the time of reading. The BMS algorithm has changed slightly from time to time. But even then the crowd sourced data showed a lower degradation than the reading from...

Hi, I also own a S85 with about 75.000 miles, but it lost only about 5 miles after the update, so far. I think degradation of the battery wasn't defined very well, so far. We all thought that the current amount of energy available at full charge of 4,2 V divided by the amount of energy of a...