Wiki Sudden Loss Of Range With 2019.16.x Software

[mvotb]

Sorry to be mostly absent. I need to maintain my sanity and as long as I have v8, I remain in my perfect little unaffected world with my barely degraded battery and my 118KW super charging speeds.

I know that could all come crashing down on me should I screw up my vudu magic routine that includes:

• Null wifi hotspot
• Rear door handle fuse removed(except when I have company).
• Drivers door cracked when I'm at home (have always done this to reduce wear and tear cycles on the pivot gear).
• Rear hatch open.
• Frunk open.
• Manual power down every time I get out.

Hoping the vudu continues to ward off the evil "software adjustment" darts from the sky.

Any important news in the last thousand 500 or so posts?

Ut Oh, You may have given them the recipe to cook your goose. Maybe get one of those lead lined vests from the dentists office for your mirror. Hmm, I was joking, but actually wish I would have tried it now. Fight on, do not become assimilated.

 

[Droschke]

Is this correct? I don't think it will report a higher Wh/mile, the battery just holds less Wh. It will be more %/mile, but not Wh.

The poster, Dutchmeeuw, who you are asking this question started this thread. Read his last post in this thread on July 9 and what he said at the end of his post out of frustration with Tesla:

Sudden Loss Of Range With 2019.16.x Software

 

[raphy3]

For those who have been claiming throughout the thread that various users have been foolish or unrealistic when they claim they previously had no degredation, go check this paper, for example. In this one they study specifically Tesla's chemistry and show that using the lower range of the discharge cycle, you can acheve almost no degredation (1.4% cited here).

https://pubs.acs.org/doi/full/10.1021/acsenergylett.9b00733#

While the paper claims that driving with only 60% depth of discharge is unreasonable, this is precisely what many owners do. Plenty do 50% (20-70). they baby their cars, and it's not unreasonable for them to have expected only minor degredation.

If you read and understand this paper, you'll already begin to see that degredation doesn't mean that max voltage is automatically lower. I suspect that some people understand that voltage and depth of discharge are in fact linked, and that charging to a lower max voltage and discharging to a lower min voltage inceases cell cycle lifetime. So, understanding that storing a higher voltage at the anode leads to damage, people seem to be incorrectly extrapolating that the result of the damage is a reduced possible maximum voltage on the anode/cathode. This is incorrect. Degredation of battery capacity definitively does not mean reduced maximum voltage. There are more than two decades worth of empirical data to support this claim throughout the literature.

You may also be interested in this talk from NREL: https://www.nrel.gov/docs/fy14osti/62813.pdf
In the very first slide you'll see a plot that very clearly shows that battery capacity in Ah, which is dependent on cycles, does not affect the maximum voltage or even the voltage during the middle of the cycle for 100% depth of discharge.

In fact, for everyone harping on voltage, what you need to understand is that it is the voltage at the lower end of the depth of discharge that is most affected by degredation and reduced capacity. That is, the instantaneous cell voltage as a function of discharged Ah will drop faster as batteries age, and a lower voltage will be reached for a smaller Ah discharge. Once voltage drops too low, there is not enough chemical potential to move Li ions. Current stops flowing. This has nothing to do with the maximum voltage the battery can be charged to. What then causes the reduction in Ah if it's not max voltage reduction? It's a reduction in the number of free Li ions to move between the anodes. For example, the ions can become trapped in the anode/cathode material itself due to chemical reduction. Here's one example: Transition Metal Dissolution, Ion Migration, Electrocatalytic Reduction and Capacity Loss in Lithium-Ion Full Cells
Even worse than trapping in electrodes, the electrolyte can also solidify, which will increase resistance to ion movement, and even can freeze ions in place within the electrolyte. Battery capacity is measured in current multiplied by time. Less available mobile ions to flow means that a given current flows for a decreasing amount of time for a decreasing amount of total free ions. It's the "h" in the Ah that is reduced when battery capacity goes down due to degredation. Not the voltage. You don't even have the units right.

In fact you can charge a battery beyond 4.2V. The 4.2V number just comes from an industry standard, above which massive damage to the battery results with only a few cycles of high DoD has been empirically established over many years of research. Here is a recent example: https://pubs.acs.org/doi/10.1021/acsenergylett.7b00304
So of course Tesla's move to cap the battery max voltage can be interpreted as a way to attempt to stop rapid degredation that they previously didn't anticipate. The number one way to increase a battery's lifespan is to limit the DoD. This is common knowledge.

Finally, a post containing a ton of technical papers was posted a while back and mostly has been ignored. See here: Sudden Loss Of Range With 2019.16.x Software
While most of those links deal with the concept of lithium plating, it's very easy to find plenty of resources that empirically determine how voltage, Ah, and DoD are interrelated and what types of damage occurs at electrodes and also resources which provide numerical models of the same to predict lifetimes of future cells.

 

[raphy3]

If you want to know more about the 18650 cell and degredation, read this thesis: https://mediatum.ub.tum.de/doc/1355829/1355829.pdf

 

[Guy V]

It seems that some amount of lithium plating is an unavoidable consequence of most EV battery usage which almost always encounter charging under less than ideal conditions. But it can be reduced or minimized or possibly some of it reversed by actions by the BMS. It is likely that the software update is exactly what you are advocating here.



But you do have to actually read and understand the sentences and attribute meaning to them and determine what the precise term of a contract is and whether they create any contractual obligations and if so what exactly is the nature of the contractual obligation. Some sentences in contracts do not create obligations but are merely representations. And then if those representations turn out to be false, that could (in combination with another term of the contract) create an obligation.

In this case the sentence you like is simply a statement of fact. Tesla cannot breach that sentence, and that sentence does not create any duty for Tesla and it doesn't create any remedy for the customers.

The second sentence does specify the duty for Tesla (namely by limiting the duty), and correspondingly limiting the remedy for owners.
Namely, "Loss of Battery energy or power over time or due to or resulting from Battery usage is NOT covered under this Battery and Drive Unit Limited Warranty"

That limit isn't changed by the fact that the declarative sentence is true "The Battery, like all lithium-ion batteries, will experience gradual energy or power loss with time and use." Also not knowing the specific details we don't know that just because the battery charged to 4.2v and the reported range was whatever it was, because of some other battery condition the actual range available could have already degraded, especially when you realize that all performance of the battery is performance within certain limits of the BMS which were in place on day one, and those limits have been continually refined, as they should be.




I agree, but such is the necessary decision-making balancing the interests of keeping proprietary trade secrets, alleviating the anxiety and concerns of affected customers, and perhaps simply not having sufficient clear technical detail that even could be shared. That's the (to me, small) cost of using new technology that is still being developed, tweaked and understood.

And that in no way changes my conclusion that followed:

Tesla offered the Model S with numerous fitness for use qualities, and specifically assurances of batteries managed no-worry for long life and dependability, warranted for 8 years and unlimited miles. It supported those claims and warranties for years until suddenly not.

If the product is unable to meet it's performance claims in normal usage due to a materials failure it is an engineering fault, a design flaw that is the responsibility of the manufacturer to remedy. There are many, and sometimes very very expensive examples of that, some legally forced, and some to maintain a business reputation to support continued access to the marketplace.

Tesla will find that it has to resolve this issue for it's customers one way or another.

 

[doctorwho]

The nhtsa investigation and lawsuits are working. They gave back the first scraps of what they stole the day after the class action was filed, and they are now giving back a little more only days after being served an ultimatum from the NHTSA. They can keep giving back scraps little by little because they took so much... This latest scrap increases volts to 4.1v (about 90% of actual, so they've returned roughly half under duress)

According to TeslaFi battery report, I've lost an additional 2km range with the upgrade to v10. That's probably within the margin of error, however, I'll do a 'useable kW' calculation and report back. Other Aussie owners with affected cars are also reporting a further reduction with v10 software

 

[Ferrycraigs]

Is this correct? I don't think it will report a higher Wh/mile, the battery just holds less Wh. It will be more %/mile, but not Wh.

As I understand it, in a degraded battery, the battery struggles to hold its charge. It charges up, and depletes more quickly. This will mean it uses a higher Wh/mile figure.

 

[RobPet]

Nothing really new to add. Luckily still not affected by batterygate. Chargegate slowed a recent trip of ~820km (3 supercharging stops) down by about 30 minutes due to the new taper.

However, I just wanted to say that the first post in this thread is an excellent piece of work and anyone new to this thread should definitely read it first. It's thorough and informative. Well done!

 

[T.R.T.e.s.l.a.]

Nothing really new to add. Luckily still not affected by batterygate. Chargegate slowed a recent trip of ~820km (3 supercharging stops) down by about 30 minutes due to the new taper.

However, I just wanted to say that the first post in this thread is an excellent piece of work and anyone new to this thread should definitely read it first. It's thorough and informative. Well done!

What typical rage do you get when you charge to 100%?
And what did you got when your car was new?
I have a Nov. 2014 S85, but bought it second had so i don't know what range did it had when new.

 

[RobPet]

What typical rage do you get when you charge to 100%?
And what did you got when your car was new?
I have a Nov. 2014 S85, but bought it second had so i don't know what range did it had when new.

371. Was ~395-400 when new.

I need to actually check the capacity. However, my first leg of this recent trip was ~280km with about 1 degrees celcius and German autobahn speeds. Used up 97% and it showed ~69 kWh used (so 72 kWh usable, or 7% degradation).
So after 150k km, I believe my degradation is between 6-7%.
I am on 2019.12.3.

About supercharging:
Highest peak power I've seen from the supercharger was 128 kW. Yet around 40% SoC charger power is around 70 kW and at 60% SoC, about 40 kW. This used to be about 85 kW and 60 kW. Charging to 50% takes about 5 min longer, charging to 80% about 15 min longer. Charging to 100% on a supercharger is near impossible as it takes well over 1.5 hours to even get above 90% (this used to be about 1 hour and 10 minutes) and then another hour for the last 10%.
Luckily here in (western) Europe the SuCs are close enough together to rarely need more than 80%. To ~60% should get you to the next one easily, so the extra time needed is not 'end of the world'. You feel like a slowpoke compared to the coming and going Raven S/X and Model 3s, though.

If you do need the high % SoC, which I believe is sometimes needed in parts of the US, the new charging profile really sucks.

Look forward to whatever comes out of the NHTSA evaluation/investigation as well as the mediation.

 

[bijan]

As I understand it, in a degraded battery, the battery struggles to hold its charge. It charges up, and depletes more quickly. This will mean it uses a higher Wh/mile figure.

The BMS "knows" that the battery is degraded, since it measures the charge going in. If a 90kwh battery is 50% degraded the BMS knows that 100% SoC is now 45kWh (since only 45kWh went in) and the wh/miles or wh/km will still be accurate however the % will go down twice as fast.

Edit: If the BMS didn't know it was degraded it wouldn't be able to show less rated miles to indicate degradation. (If that were the case and it still showed the original number of rated miles, then wh/km would indeed drop faster)

 

[bhzmark]

I would also think that Case 1 is also warrantable. From the get-go, Tesla encouraged us to drive, drive, drive. They put their money where their mouth is by proclaiming an eight-year unlimited mileage warranty on the battery and BMS. There were no caveats on our driving.

Which sentence in the warranty do you think makes it warrantable? This clear sentence below indicates that battery degradation caused by usage is specifically non-warrantable. You just simply can't ignore that language or pretend that it doesn't exist.

"Loss of Battery energy or power over time or due to or resulting from Battery usage is NOT covered under this Battery and Drive Unit Limited Warranty"

ordinary usage should not nullify the warranty claim on these batteries if the batterygate software is in response to this lithium plating problem.

Usage doesn't "nullify" the warranty -- but loss of energy or power resulting from usage (e.g., lithium plating) is simply not covered.

So, understanding that storing a higher voltage at the anode leads to damage, people seem to be incorrectly extrapolating that the result of the damage is a reduced possible maximum voltage on the anode/cathode. This is incorrect. Degredation of battery capacity definitively does not mean reduced maximum voltage.

I don't know who stated that the damage (e.g., lithium plating damage due to usage) results in a reduced possible maximum voltage on the anode.

Instead it seems to me that when certain damage (perhaps due to usage?) is identified (e.g., by measuring Condition Z to see if it reaches a trigger level?) then the BMS takes action (like it does in response to many other triggers) and limits to voltage.

the instantaneous cell voltage as a function of discharged Ah will drop faster as batteries

except when lithium plating causes voltage plateaus?

Tesla's move to cap the battery max voltage can be interpreted as a way to attempt to stop rapid degredation that they previously didn't anticipate. The number one way to increase a battery's lifespan is to limit the DoD. This is common knowledge.

exactly.

Tesla offered the Model S with numerous fitness for use qualities, and specifically assurances of batteries managed no-worry for long life and dependability, warranted for 8 years and unlimited miles. It supported those claims and warranties for years until suddenly not.

What Tesla offered, in black and white plain english was a "limited" warranty. And one of the limits was:
"Loss of Battery energy or power over time or due to or resulting from Battery usage is NOT covered under this Battery and Drive Unit Limited Warranty"

What you have to do is find facts to support is that Condition Z reaching the trigger level is a warrantable manufacturing defect or a battery failure rather than simply battery wear from usage, such as lithium plating. I see no evidence supporting that yet but it is entirely possible.

So far it all points towards wear from usage, probably lithium plating, since only relatively few batteries are affected, rather than lots of them. And the affected batteries do not seem to be from a particular batch of batteries (which would suggest a manufacturing defect) but rather are spread out with no pattern discerned.

 

[Chaserr]

Is this correct? I don't think it will report a higher Wh/mile, the battery just holds less Wh. It will be more %/mile, but not Wh.

No he's wrong and you're correct. A degraded battery has roughly the same wh/mile but less usable capacity when charged to the original 4.2v 100% value.

The BMS "knows" that the battery is degraded, since it measures the charge going in. If a 90kwh battery is 50% degraded the BMS knows that 100% SoC is now 45kWh (since only 45kWh went in) and the wh/miles or wh/km will still be accurate however the % will go down twice as fast.

Edit: If the BMS didn't know it was degraded it wouldn't be able to show less rated miles to indicate degradation. (If that were the case and it still showed the original number of rated miles, then wh/km would indeed drop faster)

Right. It knows it reached 100% because the cells report 4.2v and volts are the way the BMS determines charge %. If it can't charge as many kWh at 100% as it used to, it recalculates usable capacity.

 

[bijan]

Which sentence in the warranty do you think makes it warrantable? This clear sentence below indicates that battery degradation caused by usage is specifically non-warrantable. You just simply can't ignore that language or pretend that it doesn't exist.

"Loss of Battery energy or power over time or due to or resulting from Battery usage is NOT covered under this Battery and Drive Unit Limited Warranty"



Usage doesn't "nullify" the warranty -- but loss of energy or power resulting from usage (e.g., lithium plating) is simply not covered.

Usage may have caused lithium plating, but lithium plating doesn't cause reduced capacity and it definitely doesn't cause voltage capping. The voltage capping is not a result of use, it's a result of Tesla's software change to the BMS.

 

[Droschke]

For those who have been claiming throughout the thread that various users have been foolish or unrealistic when they claim they previously had no degredation, go check this paper, for example. In this one they study specifically Tesla's chemistry and show that using the lower range of the discharge cycle, you can acheve almost no degredation (1.4% cited here).

https://pubs.acs.org/doi/full/10.1021/acsenergylett.9b00733#

While the paper claims that driving with only 60% depth of discharge is unreasonable, this is precisely what many owners do. Plenty do 50% (20-70). they baby their cars, and it's not unreasonable for them to have expected only minor degredation.

If you read and understand this paper, you'll already begin to see that degredation doesn't mean that max voltage is automatically lower. I suspect that some people understand that voltage and depth of discharge are in fact linked, and that charging to a lower max voltage and discharging to a lower min voltage inceases cell cycle lifetime. So, understanding that storing a higher voltage at the anode leads to damage, people seem to be incorrectly extrapolating that the result of the damage is a reduced possible maximum voltage on the anode/cathode. This is incorrect. Degredation of battery capacity definitively does not mean reduced maximum voltage. There are more than two decades worth of empirical data to support this claim throughout the literature.

You may also be interested in this talk from NREL: https://www.nrel.gov/docs/fy14osti/62813.pdf
In the very first slide you'll see a plot that very clearly shows that battery capacity in Ah, which is dependent on cycles, does not affect the maximum voltage or even the voltage during the middle of the cycle for 100% depth of discharge.

In fact, for everyone harping on voltage, what you need to understand is that it is the voltage at the lower end of the depth of discharge that is most affected by degredation and reduced capacity. That is, the instantaneous cell voltage as a function of discharged Ah will drop faster as batteries age, and a lower voltage will be reached for a smaller Ah discharge. Once voltage drops too low, there is not enough chemical potential to move Li ions. Current stops flowing. This has nothing to do with the maximum voltage the battery can be charged to. What then causes the reduction in Ah if it's not max voltage reduction? It's a reduction in the number of free Li ions to move between the anodes. For example, the ions can become trapped in the anode/cathode material itself due to chemical reduction. Here's one example: Transition Metal Dissolution, Ion Migration, Electrocatalytic Reduction and Capacity Loss in Lithium-Ion Full Cells
Even worse than trapping in electrodes, the electrolyte can also solidify, which will increase resistance to ion movement, and even can freeze ions in place within the electrolyte. Battery capacity is measured in current multiplied by time. Less available mobile ions to flow means that a given current flows for a decreasing amount of time for a decreasing amount of total free ions. It's the "h" in the Ah that is reduced when battery capacity goes down due to degredation. Not the voltage. You don't even have the units right.

In fact you can charge a battery beyond 4.2V. The 4.2V number just comes from an industry standard, above which massive damage to the battery results with only a few cycles of high DoD has been empirically established over many years of research. Here is a recent example: https://pubs.acs.org/doi/10.1021/acsenergylett.7b00304
So of course Tesla's move to cap the battery max voltage can be interpreted as a way to attempt to stop rapid degredation that they previously didn't anticipate. The number one way to increase a battery's lifespan is to limit the DoD. This is common knowledge.

Finally, a post containing a ton of technical papers was posted a while back and mostly has been ignored. See here: Sudden Loss Of Range With 2019.16.x Software
While most of those links deal with the concept of lithium plating, it's very easy to find plenty of resources that empirically determine how voltage, Ah, and DoD are interrelated and what types of damage occurs at electrodes and also resources which provide numerical models of the same to predict lifetimes of future cells.

If you want to know more about the 18650 cell and degredation, read this thesis: https://mediatum.ub.tum.de/doc/1355829/1355829.pdf

@raphy3 - Thanks so much for an excellent post to clarify, once more, but in more eloquent detail this time the facts readily available for those willing to learn instead of posting opinions.

All referenced links can be found in the wiki post#1 as well.

 

[mattwhite]

Which sentence in the warranty do you think makes it warrantable? This clear sentence below indicates that battery degradation caused by usage is specifically non-warrantable. You just simply can't ignore that language or pretend that it doesn't exist.

"Loss of Battery energy or power over time or due to or resulting from Battery usage is NOT covered under this Battery and Drive Unit Limited Warranty"

There has to be some amount of battery degradation caused by usage over a given time period that would legally be considered warrantable. Could Tesla sell a car with a battery that fully degraded in three years and it not be a warranty issue? Two years? One year? 6 months? 1 month? Some amount of degradation within some time frame will cause the car to be unable to be used for its intended purpose, making battery degradation a warrantable issue. It is not solely Tesla's prerogative to decide what this time period is, post-sale.

The earlier post that basically said we are in unchartered legal waters with these issues is spot on. All the state and federal laws relating to new car warranties were written around cars with traditional ICE powertrains. There will be new court cases, as well as additional federal regulations and possibly statutory law to sort all this out. Tesla's unreasonable, extremely shortsighted, conduct in relation to voltage capping via software updates without any explanation will only serve to force the government's hand sooner.

 

[raphy3]

Instead it seems to me that when certain damage (perhaps due to usage?) is identified (e.g., by measuring Condition Z to see if it reaches a trigger level?) then the BMS takes action (like it does in response to many other triggers) and limits to voltage.

This is ancillary. The point that was made by several people in the thread was that "we don't know" that max voltage reduction is a separate issue from degredation. That's wrong. The literature blows the idea that "we don't know" that max voltage is maintained with degredation out of the water.
Even lithium plating does not reduce max voltage.

By the way, whether lithium plating occurs from "usage" does not automatically make it uncovered by warranty. As has been stated by others in the thread, Tesla has enough knowledge of the state of the art to know how to design their BMS to make plating a very slow process. That they didn't do this constitutes a mistake. Per their advertisements for their cars, mistakes made by Tesla or the user are fully covered under the
warranty.
Finally, "usage" won't hold up in court. In court the conversation will quickly move to "reasonable". That is, what damages are considered reasonable as arises from normal usage? Everything else is a defect. It would be hard to prove, but one could prove Tesla made an error which caused ureasonable damage due to normal usage. Discovery would help establish evidence for that.

 

[T.R.T.e.s.l.a.]

371. Was ~395-400 when new.

I need to actually check the capacity. However, my first leg of this recent trip was ~280km with about 1 degrees celcius and German autobahn speeds. Used up 97% and it showed ~69 kWh used (so 72 kWh usable, or 7% degradation).
So after 150k km, I believe my degradation is between 6-7%.
I am on 2019.12.3.

About supercharging:
Highest peak power I've seen from the supercharger was 128 kW. Yet around 40% SoC charger power is around 70 kW and at 60% SoC, about 40 kW. This used to be about 85 kW and 60 kW. Charging to 50% takes about 5 min longer, charging to 80% about 15 min longer. Charging to 100% on a supercharger is near impossible as it takes well over 1.5 hours to even get above 90% (this used to be about 1 hour and 10 minutes) and then another hour for the last 10%.
Luckily here in (western) Europe the SuCs are close enough together to rarely need more than 80%. To ~60% should get you to the next one easily, so the extra time needed is not 'end of the world'. You feel like a slowpoke compared to the coming and going Raven S/X and Model 3s, though.

If you do need the high % SoC, which I believe is sometimes needed in parts of the US, the new charging profile really sucks.

Look forward to whatever comes out of the NHTSA evaluation/investigation as well as the mediation.

Thank you for the detailed information.
Lately i get 372 km of range when i charge to 100% and have 105k km.
At Scan My Tesla i get 74,4 or 74,05 kWh of Nominal full pack and 70,4 or 79,5 kWh of Usable full pack.

I too am getting around 70 kw at 40% at Suc, but at 60% i'm a bit better than you since i'm getting 49 kw, but this only after the V10 update because previously (after chargegate, obviously) i was getting between 40 and 44 kw at 60%.

BTW i'm also in Europe, Portugal.

 

[jensk2]

That is very interesting. Then, looks like you are in that "test group" you did not volunteer for.

For the record, I have received 2019.32.2.2 three times Perhaps, what is updated is a subsystem (BMS?) that have an internal version number we cannot see. (My range is unaffected, but SC is slow)

 

[Ferrycraigs]

I was asked by a friend for further explanation on the volts bit, as he was sure from his school days that volts in a cell do go up and down. But I was saying they don’t. He is correct. Yes they do. The volts I am talking about, in relation to the degradation point, is an upper limit rather than the amount of charge a cell stores.

There are two separate issues here. The amount of volts that the cell is designed to accept, ie the range of charge. And the amount of charge a cell is actually holding at any one time. They are related but different, but it’s easy to see why there might be confusion.

First one: the Volts each cell is designed to accept. A battery is designed to accept a range of energy, ie the range between empty and full. If it takes on too much, or loses too much, it damages the cell. So BMS software sets an upper and lower level. There is a maximum figure (Vmax) and a minimum figure (Vmin). Although it’s a poor example, think of it like a fuel tank. When all the cells are at Vmax, the total charge (in a 70 kWh battery) equals 70 kWhs. And when it’s at Vmin, the available charge is 0 kWhs. But if you change the Vmax to a lower figure, (which is what Tesla appear to have done) then the tank is suddenly smaller. So it’s a bit like changing a 70 gallon tank for a 60 gallon tank. Then when the customer complains that the car won’t go as far, the maker says, nothing is wrong, your fuel tank is healthy, it’s just normal wear and tear from driving. You are still getting the same range as other cars of similar age and mileage. Erm no. It’s because the size of the fuel tank has been changed. And just like Volt Capping, however much the engine wears out, the fuel tank still stays the same size. This is why volt capping isn’t degradation. Volt capping is changing the size of the fuel tank. Degradation, however severe, will not change Vmax. That can only be done artificially.

Second one: How much the cell holds, sometimes referred to as Open Circuit Voltage, is entirely dependant on the State of Charge. At full SoC it should hold 4.2V. At low SoC it may only hold 3.1V or so. In a badly degraded battery, whilst it will still try to charge up to 4.2V, it may not manage. But the 4.2V limit will still be there. Which is why in older EVs, the max charge reduces to a figure below 100%.

So, yes, the voltage in an individual cell certainly does go up and down. And degradation will have an effect on that. Voltage capping is just changing the size of the fuel tank. Reducing the size of the fuel tank (battery) reduces the battery's available capacity, which in turn produces less range. But this sudden loss has nothing to do with degradation. It’s to do with the sudden reduction in the size of the fuel tank.

Hope that helps. Sorry if I have caused confusion.