Model 3 performance degradation w/ battery degradation?

[Dolemite]

Tried searching, but battery degradation is so widely discussed that I can't find results specific to performance degradation as a result of battery degradation.

Could someone actually knowledgable chime in on whether this is even a tangible concern or typical forum FUD? I wouldn't even have thought of it, but I came across a post of someone claiming that within a few years, our cars would no longer be producing peak power due to battery age.

Applying the typical internet misinformation factor of 80% leaves me to wonder whether there's any truth to this at all, or whether the truth is so imperceptible that it doesn't qualify as a valid concern.

 

[kbecks13]

It's a good question, i think it's tough for people to quantify so it's typically not discussed as much as battery degradation which we can measure relatively easily. I'm getting one of those CAN harnesses and the Scan My Tesla app to track some of this data, could possibly find a way to record peak power over time i suppose.

 

[Tessaract]

Tried searching, but battery degradation is so widely discussed that I can't find results specific to performance degradation as a result of battery degradation.

Could someone actually knowledgable chime in on whether this is even a tangible concern or typical forum FUD? I wouldn't even have thought of it, but I came across a post of someone claiming that within a few years, our cars would no longer be producing peak power due to battery age.

Applying the typical internet misinformation factor of 80% leaves me to wonder whether there's any truth to this at all, or whether the truth is so imperceptible that it doesn't qualify as a valid concern.

It's true that generating peak power from the motor(s) requires a battery voltage to be higher than some minimum voltage, close to the "fully charged" voltage. It also requires the batteries to be capable of supplying peak currents greater than some minimum value. Which is why the smaller batteries will enable smaller peak power (like the Model SR vs the LR).

A third quantity is battery capacity, which is the measure of how much energy can be stored in the battery. When we talk about battery degradation, we're generally referring to the degradation in battery capacity. Degradation in capacity is not the same as degradation in battery voltage or max current.

A fourth quantity is the displayed vehicle range. This quantity is theoretically most closely related to battery state of charge (SoC), but the algorithm that Tesla uses to measure battery SoC is unknown to me, and to almost every Tesla motorist. (If anyone has expertise on this subject, and is not merely guessing, I'd be curious to hear it).

What most people observe as "battery degradation" is the diminution of max displayed range, which is really the diminution of the vehicle-calculated SoC. This is not the same as battery capacity degradation (which is what triggers Tesla warranty repair), nor the same as diminution of battery voltage and max current. So it's entirely likely that peak power is not decreased by observed range degradation, presuming this doesn't fall below some minimum value. It is however, entirely possible that general battery degradation that substantially decreases the battery max current or voltage could decrease peak power. However, most speculation on this subject is likely not technically well-informed, and not practically credible.

 

[Dolemite]

Saw this article today:

https://www.washingtonpost.com/technology/2020/01/10/tesla-battery-range/#comments-wrapper

As the batteries age, however, they become less potent, which can affect the driving experience. “As the battery degrades, you won’t be able to do the 2.5 seconds-fast acceleration because the battery can’t deliver as much power in that time as it did before,” he said. The range decreases and charging time goes up and available power lessens — which can translate to the driving experience, he said.

Guy seems pretty credible... would love to hear what the "real world" impact of this may be. I've heard that the battery can delivery WAY more current than the motors could ever handle, so if it's getting to the point where it's affecting performance, things must be getting pretty dire. But that's just a guess.

 

[AdamVIP]

Its not wrong that performance will go down but that happens on any aging car. Things get worn out and tolerances loosen.

 

[Dolemite]

Its not wrong that performance will go down but that happens on any aging car. Things get worn out and tolerances loosen.

What I'm interested in is - to what extent should we expect this on an EV? I'd argue that it should be fairly imperceptible degradation relative to an ICE car that has cylinders that wear down - an electric motor only has a couple of bearings that'll probably last the life of the car. Same with the gears etc. that they're attached to.

 

[ElectricIAC]

I feel like this should be tested on platform known for very poor degradation curves like Leaf. It won’t be 1:1 but give an idea at least of what one should expect.

 

[kailm]

What I'm interested in is - to what extent should we expect this on an EV? I'd argue that it should be fairly imperceptible degradation relative to an ICE car that has cylinders that wear down - an electric motor only has a couple of bearings that'll probably last the life of the car. Same with the gears etc. that they're attached to.

Example: batteries have peak amperage of lets say 1200A at full charge. For you to achieve your said 0-60 you require 1000A, so basically as it degrades to 1000A at full charge, you will get your performance only at 100% charge. Anything less will not give you same acceleration of your 0-60 benchmark. Now how it drives will vary because while already in motion you don't need your 1000A, you might need 500A to overtake and such. So theoretically, it will drive fine, but your track performance will degrade if your slowing down a lot and then accelerating back up. This is mostly due to battery.
Motor will probably produce peak power for a long time, lets say 200k miles for a 1M mile motor.

My P3D- is at 284mi at 100% (winter), It is expected as high amperage draw will degrade battery faster than driving it on chill all the time.
Heater will also cause faster battery wear without miles being driven.
Low drain is the best way to get max life out of the battery.

They should really add a gas car mode, below chill mode, like mazda just did for their ev.

 

[Uncle Paul]

Normally, I would think the OP is onto something. It would be expected that as your battery degrades, the performance will be reduced at the same time.

But with Tesla, it has been a different. Both my vehicles have gotten faster, even as they aged. Tesla has, on several occasions, increased the performance of my (and others) cars via OTA updates. My 75X got an uncorking that increased acceleration by over 1 second 0-60. Not long ago they also increased my performance by 3-5% by downloading newer algorithms.

All my ICE cars would get slower with age, as their rings and valve seats got worn, and compression was reduced.

Simply amazed at how much better Tesla gets with age.

 

[ElectricIAC]

Example: batteries have peak amperage of lets say 1200A at full charge. For you to achieve your said 0-60 you require 1000A, so basically as it degrades to 1000A at full charge, you will get your performance only at 100% charge. Anything less will not give you same acceleration of your 0-60 benchmark. Now how it drives will vary because while already in motion you don't need your 1000A, you might need 500A to overtake and such. So theoretically, it will drive fine, but your track performance will degrade if your slowing down a lot and then accelerating back up. This is mostly due to battery.
Motor will probably produce peak power for a long time, lets say 200k miles for a 1M mile motor.

My P3D- is at 284mi at 100% (winter), It is expected as high amperage draw will degrade battery faster than driving it on chill all the time.
Heater will also cause faster battery wear without miles being driven.
Low drain is the best way to get max life out of the battery.

They should really add a gas car mode, below chill mode, like mazda just did for their ev.

Rated miles I take it? At 100%? I guess I shouldn’t feel too bad then showing 298 on my P3D+

 

[kailm]

Rated miles I take it? At 100%? I guess I shouldn’t feel too bad then showing 298 on my P3D+

Correct. Im at 24k miles now. Owned for ~14 months.

 

[ElectricIAC]

That’s pretty steep. You might consider doing a full drain and full charge to see if any improvement..

Personally I saw *full drain* at 68kwh pulling into an SC at 0%. Not something I would do often but it brought my initial 291 up to 299 and latest update went down to 298.

 

[Dolemite]

Motor will probably produce peak power for a long time, lets say 200k miles for a 1M mile motor.

Call me insane but I wouldn't be surprised if the motors produced peak power well past 500K miles. The one and only weak link is the battery, which is difficult to understand. I'm looking forward to the day when we can DIY a battery swap for like $5K.

I'm gonna keep digging on this.

 

[Msjulie]

I wonder about some details; perhaps Nissan changed battery chemistry but what still haunts them most appears to be the decision to avoid effective thermal management for the battery. Are there other "facts" in the article similarly not quite right? IE

"One example is Tesla’s decision to opt for dual-motors for its front and back wheels over using multispeed transmissions to increase power."

Multi-speed? Multi-gear? What is that supposed to say?



It is true that the chemistry in Tesla cells have higher energy density than many and require the careful thermal management. Is that bad or just fact?

I took an EV conversion class and the cells used there were pretty low energy in comparison but supposedly the trade off was very good stability over a wide range of temperatures, something more likely to be encountered in a DYI electric car. Safety over range for a purpose.

 

[N54TT]

 

[Tessaract]

I wonder about some details; perhaps Nissan changed battery chemistry but what still haunts them most appears to be the decision to avoid effective thermal management for the battery. Are there other "facts" in the article similarly not quite right? IE

"One example is Tesla’s decision to opt for dual-motors for its front and back wheels over using multispeed transmissions to increase power."

Multi-speed? Multi-gear? What is that supposed to say?



It is true that the chemistry in Tesla cells have higher energy density than many and require the careful thermal management. Is that bad or just fact?

High temperatures and large temp swings are the enemy of long life and reliability for all physical systems (includes mechanical components, batteries, electronics, lubricants, etc.). This is true regardless of the battery chemistry or composition of the materials concerned. So much so, that standard reliability tests include "high temp operation", "temp cycling", and similar tests to stress parts under test and thereby demonstrate reliability. Given this, Nissan's decision to not include thermal management for their most expensive Leaf component, the battery, guaranteed larger temp cycles for the battery, increasing it's stress and reducing it's reliability, and was one of the most bone-headed design decisions ever made.

The "multispeed" transmission quip is both true and false depending on your perspective. All ICE AWD vehicles have a front/rear differential (sometimes physically housed within the transmission) to split the engine power between front and rear wheels. This splitting of power does incur some power loss (as any gear train will incurr power losses due to friction). Assuming for the moment that the Tesla front and rear motors have the same total power as an ICE engine driving both front and rear, then the dual motors don't increase power per se, but do avoid the losses of the power-splitting differential.

I think the dual motor configuration is a design decision that's completely independent of "multi-speed" transmissions, though. Electric motors all by themselves usually (but not always: see Porsche Taycan) eliminate the need for multi-gear (a more technically precise word for multispeed) transmissions.

 

[ZOMGVTEK]

Over time the internal resistance of the cells will increase, and this is going to happen somewhat independently of the capacity loss. How much this impacts vehicle performance is going to depend mainly on how hard the battery is run relative to its absolute ability. And with Tesla, it appears they run the battery quite hard, so it’s very likely you will see worse battery performance over time. This would be realized as a reduction in the peak power the battery will produce, and the charge speed is more likely to be slightly lower and taper earlier. You can design an EV that has no noticeable degradation or impact from cell aging, but this basically just means you’re leaving power on the table from the factory. It’s largely up to how the vehicle is designed, and it costs more to put more battery in than you need, so it’s unlikely you won’t see some impact to the vehicles performance as time goes on. Internal resistance is generally a better indicator of cell health than capacity, but Tesla is probably not too keen on providing any data on this. But all indicators point towards the performance variant suffering the most, the LR RWD or possibly SR suffering the least.

 

[Dolemite]

The "multispeed" transmission quip is both true and false depending on your perspective. All ICE AWD vehicles have a front/rear differential (sometimes physically housed within the transmission) to split the engine power between front and rear wheels. This splitting of power does incur some power loss (as any gear train will incurr power losses due to friction). Assuming for the moment that the Tesla front and rear motors have the same total power as an ICE engine driving both front and rear, then the dual motors don't increase power per se, but do avoid the losses of the power-splitting differential.

For the center diff, yes, but the Model 3 does have a differential for its motor(s)... otherwise it's putting its power down through magic.

 

[Black306]

Beat me to it.

I believe the performance loss is mostly in the batteries. That said, reviving and actually improving the performance in an EV should be easier. With an ICE car, installing a more modern engine can be a pain in the butt. Plus, it might not even be legal. (Thanks CARB! )

With an EV, 20 years from now batteries will get better; they’ll have more punch, more capacity, lighter weight, or a combination of the three. Installing more modern batteries will be a matter of reconfiguring the modules within the battery enclosure; assuming there is an alternative to the 2170 size battery. I wouldn’t be surprised if you could eventually buy a replacement battery module/pack at Autozone. LOL

 

[DionG]

Do the batteries run at peak now.? Because there was a update that added a little faster run, and then a 2k acceleration boost .. did those batteries run at peak prior? If not is there more boost available down the road. If not is it now at peak? Is there buffer to prevent absolute peak?
I believe they had a bigger buffer than they needed so the sold you back a parting of that buffer. I would think it’s safe to think there won’t be more coming. But who knows. I didn’t expect them to have available 2 boosts so close to each other