Long Term Battery Costs, Fears, and Serviceability

[fhteagle]

That’s good results for that pack, and was it even charged carefully or was it charged to 100% on a regular basis and at 0% at regular basis?

The Volt doesn't have a charge target that you can set. If it's plugged in, it goes to ~85% SOC on the top end, and will bring the ICE range extender on at around ~25% SOC IIRC. Though I can bring the ICE on earlier in Hold or Mountain mode.

Car really won't let you go too deep into the bottom end. But I've had the battery "full" from charging then go regen straight down 1000' decent. That pushes the cells a bit over the 4V design top end according to my OBD readout. So no, this pack has been far from babied. I don't have an exact number but it's probably well north of 1500 FCE at this point.

Granted, there have been cell, module, etc failures on other people's Volts. I'm not trying to pretend GM's Voltec era, let alone Ultium, pack is bullet proof, far from it. I know I've been lucky with the performance of mine, but others haven't been so lucky. My post was more about the costs and third party options available to a limited run, decade old EV. Leaf support is orders of magnitude better at this point, even if Leaf pack longevity really isn't.

 

[SageBrush]

where have they lasted longer than Tesla expected? The oldest Tesla is only like 13 years old and I think that was expected, unexpected would be 20+ years

The first Teslas for the most part did not last 13 years, they are 13 years old and plugging along. And while there have been regressions along the way, Tesla battery tech is way better now than when Tesla started out. I really do not have any doubts that in general, Tesla batteries outlast the car

 

[SageBrush]

Leaf support is orders of magnitude better at this point, even if Leaf pack longevity really isn't

That would be sad for the Volt, considering how miserable Nissan 'supports' the LEAF

 

[gottagofast]

The first Teslas for the most part did not last 13 years, they are 13 years old and plugging along. And while there have been regressions along the way, Tesla battery tech is way better now than when Tesla started out. I really do not have any doubts that in general, Tesla batteries outlast the car

I hope so I would like to see my battery last 20 years

 

[chinney]

Perhaps the biggest issues for future battery development will be cost and resource intensity. Batteries will need to be cheaper and require fewer non-plentiful resources to manufacture for them to completely revolutionize transport worldwide. They are part of the way there already, but with some way to go. As I noted earlier in this thread, there are constant stories in the media about ongoing battery developments that look promising in this regard, but seem still to be some years away from production.

 

[chinney]

A recent example, among many, of media discussion of potential future battery developments:

No Graphite? No Problem, Silicon EV Batteries Are Really Coming

 

[ev919]

You shouldn’t have to micro manage a battery, 0% SoC shouldn’t matter and 100% SoC shouldn’t matter

How old a battery is shouldn’t matter only miles/charge cycles should matter

I think that’s a big difference between batteries and ICE, your battery can degrade and go bad just by being old and never driving the car but a ice engine could last 50 years or longer if you only drove the car 1,000 - 2,000 miles per year

If you drove an ev only 1,000 - 2,000 miles per year the battery would still go bad in 10-20 years just from calendar aging, that shouldn’t happen if it wants to be exactly the same as ICE, a battery that’s 50 years old but with only 30k miles should still have 95% of its capacity

"How old a battery is shouldn't matter" and later says "your battery can degrade and go bad just by being old". Help me out here, which is it?

I hope so I would like to see my battery last 20 years

Is the "general" rule of thumb is that the ev battery (in general) degrades and looses life span about ~1% each year, so after 20 years the battery will charge say up to 80% max?

Thank you for starting this thread because this is exactly my (last) fear. My situation is, i buy car to "own". Family has 2002 (Honda Odyssey, ~220K'ish miles), 2003 (~35K'ish miles BMW E39), 2004 (~29K'ish vehicles), all "well" maintained. Were there any "single" big ticket repair item? Not really, except on Odyssey the automatic transmission (widely known issue) had to be replaced. With Honda's chipping in, can't recall the exact $ for factory replacement transmission back then, but i don't think was anywhere near the typical cost to replace Tesla battery which i'm learning (varies by models) but sure to be above $10K (for new).

So overnight got me thinking, okay, if i take care of the battery maintenance and follow (all) the charging best practices, at most at the perfect scenario, after 20 years my Tesla will hold 80% state of charge. That's like saying after 20 years my BMW will hold only 80% of the gas in the fuel tank. wtf ! But at the same time, ICE vehicles will loose mpg efficiency even the best of hybrids will, if i recall. So, loosing 1% of life expectancy in current ev battery, maybe that's ok.

But then again, you pay to play with current state with ev's, right? So, as battery technology improves, and i'm sure it will, no doubt, our current battery technology ev's, for the sake of holding "resale" values, after 20 years will be worless with 20 years old battery technology.

Maybe as what Elon stated sometime back, if the battery replacement really comes to ~$7K, then that i could live with that.

 

[gottagofast]

"How old a battery is shouldn't matter" and later says "your battery can degrade and go bad just by being old". Help me out here, which is it?


Is the "general" rule of thumb is that the ev battery (in general) degrades and looses life span about ~1% each year, so after 20 years the battery will charge say up to 80% max?

Thank you for starting this thread because this is exactly my (last) fear. My situation is, i buy car to "own". Family has 2002 (Honda Odyssey, ~220K'ish miles), 2003 (~35K'ish miles BMW E39), 2004 (~29K'ish vehicles), all "well" maintained. Were there any "single" big ticket repair item? Not really, except on Odyssey the automatic transmission (widely known issue) had to be replaced. With Honda's chipping in, can't recall the exact $ for factory replacement transmission back then, but i don't think was anywhere near the typical cost to replace Tesla battery which i'm learning (varies by models) but sure to be above $10K (for new).

So overnight got me thinking, okay, if i take care of the battery maintenance and follow (all) the charging best practices, at most at the perfect scenario, after 20 years my Tesla will hold 80% state of charge. That's like saying after 20 years my BMW will hold only 80% of the gas in the fuel tank. wtf ! But at the same time, ICE vehicles will loose mpg efficiency even the best of hybrids will, if i recall. So, loosing 1% of life expectancy in current ev battery, maybe that's ok.

But then again, you pay to play with current state with ev's, right? So, as battery technology improves, and i'm sure it will, no doubt, our current battery technology ev's, for the sake of holding "resale" values, after 20 years will be worless with 20 years old battery technology.

Maybe as what Elon stated sometime back, if the battery replacement really comes to ~$7K, then that i could live with that.

The battery degrades less over time if you keep the charge between 30-55% as much as possible for the long range and performance vehicles

 

[AAKEE]

Is the "general" rule of thumb is that the ev battery (in general) degrades and looses life span about ~1% each year, so after 20 years the battery will charge say up to 80% max?

Nope.

The 100% is refering to feeding the cells with 4.20V each until the current is below a certain limit (think - untill current stops)

A degraded battery will be able to charge to 100% but the energy it delivers will be less.

Degradation refers to delivered energy (or in some cases measured in delivered Amp-hours).
If the new cell could deliver 20Wh, and only deliveres 18Wh, it has a 10% degradation (still charges to 100%).

So overnight got me thinking, okay, if i take care of the battery maintenance and follow (all) the charging best practices, at most at the perfect scenario, after 20 years my Tesla will hold 80% state of charge.

So, the battery will not degrade 1% per year, but much more.

Calendar aging is the afing from time, and with the charging setting most people use we can expect ~ 5% the first year.

Calendar aging reduse the rate quite fast (with square root of time) so after two years you might see 7%.
After four 10%
After eight 14%
After 16 yrs 20%.
Next year, 16-17 only ”costs 0.6%.

Most Teslas hide the first 2-4% degradation so it looks better if you check the lost range.

 

[ev919]

So if following is (more or less accurate), then after 200K miles of use, the S/X batteries should remain 90% of the initially advertised EPA est. range.

Say 90% of 326 miles, so ~293.4 of usable range from battery that has 200K miles on it, using standard 10K miles driven each year.

So, after ~20 years of "normal" annual driving of 10K miles/yr (assume mostly freeway driving), "good" charging habits through out the year (hot/cold weathers) then expect to have energy left in the battery to give the car ~293.4 miles at 100% SOC ~20 years after purchase (new). At least according to Tesla's calculation.

I could live with that if that's (mostly) true. Still not great when comparing ev and hybrid suv (apple to orange comparison though comparing ev and hybrid), where hybrid, eg. Toyota 3 row hybrid should outlast in calendar aging the range/mpg by 20% more range, over the say MX battery, after ~20 years.

How Long Does a Tesla Battery Last?

A look at what Tesla says and what’s happening in the real world provides some answers to a tricky question.

www.motortrend.com

 

[karlos22]

Why would a battery need to be replaced due to degradation? Isn’t the average degradation for a 10 year old Tesla something like 10%? With LFP this becomes even less of a problem.

By the time the battery is so degraded that you will notice the car will be destined for the scrap yard.

 

[ev919]

Why would a battery need to be replaced due to degradation? Isn’t the average degradation for a 10 year old Tesla something like 10%? With LFP this becomes even less of a problem.

Good point.

Unless something else is bad, fails in battery (somewhere) i would be content with 90% range energy left in the battery, after ~200K miles on it.

 

[pyrosci]

So this is my personal framework for dealing with battery degradation, maybe interesting to some.

The aim is to have the car improve or at least not degrade over time, in day to day use. Similar to how software updates make the car better (generally speaking) over time, I want the battery to "improve" over time.

I measured the usable capacity of my M3LR during the first month to be 78.5kwh.
After 8000miles and some supercharging it is now 77.1kwh. Maybe some of the change is from calibration difference, will try a 100-0 cycle someday and see.

Anyway from day 1 I've used 80% as my "full charge", only seldomly going above this for specific reasons. Mostly I prefer to not touch the charge limit, just like charging other appliances where you don't routinely manage the charge limit.

Today I increased the charge limit to 82% to compensate for the lost capacity.

Will keep doing this (probably) until getting to 100% daily charge (maybe in 8 or 10 years time), then keep using the vehicle until there is a compelling reason to buy a replacement.

This way the car maintains its effective range and peak power over time, rather than degrading. Yes the battery chemistry itself is degrading, but this is a manual way of "hiding" the capacity loss.

This will wear out the battery sooner than staying at 80% and lower, but the concept is I don't want to feel like the car is degrading, and want to use it to its full life expectancy and capability.

If someone is unhappy about going above 80% SOC, then could start their car ownership at 70% charge limit, or 50%, and work up from there to compensate for battery degradation, or for an instant "upgrade" to vehicle usability.

 

[AAKEE]

Why would a battery need to be replaced due to degradation?

Within the warranty period it probably is very unusual.
But further on, we will see batteries that becomes tired from age.

Isn’t the average degradation for a 10 year old Tesla something like 10%?

Thats probably not true.

Tesla hides a few percent of the degradation by having the range not dropping until you lost 2-4% real battery capacity.

Looking at actual battery data, the loss is more than 10% after 10 years.

In general batteries degrades most from calendar aging, and this will be ~ 5% the first year (can be more in hot climates and less in cold, but as an average it will be around this number for cars charged to the usual numbers).

Calendar aging reduces the rate with time.
The total calendar aging is the square root of time.

So after 10 years it will be ~ 15%
The cars will show slightly less as there is ~ 2-4% hidden (My M3P did hide ~ 2% and my MS Plaid hides around 3%)

So we are to see a range reduction of ~ 12-13% after 10% in average for calendar aging. The miles add a little, but in many cases not that much.

This is real world data from teslalogger.de
S85


S85D


S P85+



S75 (no of these 10 years yet, I guess)



The oldest S85s might be 10 years, but not all of the cars. It seems like all of these 85 started displaying 426km (265mi) despite the S85D had EPA 242mi/390km.

Doing the math, we are clearly above 10% after 10 years, (around 15%) and as 20% are the common industry standard for considering the batteries consumed (starting to behave unpredictable) it would be a good idea to try to make sure the degradation stays below 20% as long as we would like to use the car with that battery.
You could be lucky and be able to drive it way beyond 20% degradation but there is no guarantee it will not develope problems.

So short term, like the first 8 years, we do not need to worry other than for the actaul reduction in range.

Long term, it might be nice to take action to make sure we keep the degradation below 20% to the end of life of the car. As calendar aging happens mostly in the early years, this should be done also early in the cars life. Starting to minimise degradation after 10 years is not bad but the biggest part has already happened at that time.

With LFP this becomes even less of a problem.

LFP’s will be affected by calendar aging just like the other chemistries.

The total degradation in perfect during the first 5-8 years probably doesnt differ much from LR cars with NCA/NMC chemistry.
Really longterm, they might look better than NCA/NMC as the cyclic aging is very low.

By the time the battery is so degraded that you will notice the car will be destined for the scrap yard.

Thats the thing, going past 20% degradation might cause the battery to start trowing failure codes.
I think we will see a lot of old cars with batteries that is too tired.
(one thing also is the build quality of Teslas and corrosion and other things starting to malfunction so if the Teslas die earlier than other cars, that might save the day for the battery.)

 

[gottagofast]

Why would a battery need to be replaced due to degradation? Isn’t the average degradation for a 10 year old Tesla something like 10%? With LFP this becomes even less of a problem.

By the time the battery is so degraded that you will notice the car will be destined for the scrap yard.

10% in 10 years? Mines at 8% already in 2 years, I hear degradation starts to slow a lot at this point though

 

[Bouba]

Is there an official way to measure degradation ?.....one which we can all agree on....where the results don’t vary depending on the time of day....I tried dividing the EPA range on screen at 100% over the same figure when the car was new...but that proved too controversial.

 

[gottagofast]

Is there an official way to measure degradation ?.....one which we can all agree on....where the results don’t vary depending on the time of day....I tried dividing the EPA range on screen at 100% over the same figure when the car was new...but that proved too controversial.

I think you can do it somewhere in your vehicles service menu but I’ve never done it, I just figure the % from the cars original epa

I wish batteries didn’t degrade so easily or much less than they do, would be nice to have a battery that only loses like 5% in 20 years, this is the only negative of EVs compared to ICE, everything else they do is better than ICE

 

[Bouba]

I think you can do it somewhere in your vehicles service menu but I’ve never done it, I just figure the % from the cars original epa

I wish batteries didn’t degrade so easily or much less than they do, would be nice to have a battery that only loses like 5% in 20 years, this is the only negative of EVs compared to ICE, everything else they do is better than ICE

I’ve never tried it either....it involves draining your car to zero and. charging to 100%....my charger is too slow for that and would take well over a day...meaning I could not use the car for the sake of the experiment and then go on a road trip to get the level down to 50% storage. Besides, the results published by forumites so far have been controversial

 

[gottagofast]

Within the warranty period it probably is very unusual.
But further on, we will see batteries that becomes tired from age.

Thats probably not true.

Tesla hides a few percent of the degradation by having the range not dropping until you lost 2-4% real battery capacity.

Looking at actual battery data, the loss is more than 10% after 10 years.

In general batteries degrades most from calendar aging, and this will be ~ 5% the first year (can be more in hot climates and less in cold, but as an average it will be around this number for cars charged to the usual numbers).

Calendar aging reduces the rate with time.
The total calendar aging is the square root of time.

So after 10 years it will be ~ 15%
The cars will show slightly less as there is ~ 2-4% hidden (My M3P did hide ~ 2% and my MS Plaid hides around 3%)

So we are to see a range reduction of ~ 12-13% after 10% in average for calendar aging. The miles add a little, but in many cases not that much.

This is real world data from teslalogger.de
S85
View attachment 1044268

S85D
View attachment 1044269

S P85+
View attachment 1044272


S75 (no of these 10 years yet, I guess)

View attachment 1044270

The oldest S85s might be 10 years, but not all of the cars. It seems like all of these 85 started displaying 426km (265mi) despite the S85D had EPA 242mi/390km.

Doing the math, we are clearly above 10% after 10 years, (around 15%) and as 20% are the common industry standard for considering the batteries consumed (starting to behave unpredictable) it would be a good idea to try to make sure the degradation stays below 20% as long as we would like to use the car with that battery.
You could be lucky and be able to drive it way beyond 20% degradation but there is no guarantee it will not develope problems.

So short term, like the first 8 years, we do not need to worry other than for the actaul reduction in range.

Long term, it might be nice to take action to make sure we keep the degradation below 20% to the end of life of the car. As calendar aging happens mostly in the early years, this should be done also early in the cars life. Starting to minimise degradation after 10 years is not bad but the biggest part has already happened at that time.







LFP’s will be affected by calendar aging just like the other chemistries.

The total degradation in perfect during the first 5-8 years probably doesnt differ much from LR cars with NCA/NMC chemistry.
Really longterm, they might look better than NCA/NMC as the cyclic aging is very low.
View attachment 1044275





Thats the thing, going past 20% degradation might cause the battery to start trowing failure codes.
I think we will see a lot of old cars with batteries that is too tired.
(one thing also is the build quality of Teslas and corrosion and other things starting to malfunction so if the Teslas die earlier than other cars, that might save the day for the battery.)

I have a question about super charging

Everyone is going to eventually take road trips during their cars life so I think it would be good to know best practices for super charging

Some trips I take could easily require 2 - 3 super charges in a single day

Is there a certain battery % that you want to start or stop at during super charging to reduce the strain it puts on the battery?

I might make 3 or 4 trips per year so that could be 24 super chargers per year or so, doing 3 super chargers in a single day though seems excessive to the battery to me though

 

[LostVector]

I have a question about super charging

Everyone is going to eventually take road trips during their cars life so I think it would be good to know best practices for super charging

Some trips I take could easily require 2 - 3 super charges in a single day

Is there a certain battery % that you want to start or stop at during super charging to reduce the strain it puts on the battery?

I might make 3 or 4 trips per year so that could be 24 super chargers per year or so, doing 3 super chargers in a single day though seems excessive to the battery to me though

I think 80 to 20 percent is the generally recommended approach. You might be able to go a bit lower in the pack for a bit more supercharging speed earlier in the charging curve.