[Article] = as I've always said don't sweat the battery lifespan -- "Researchers make surprising discovery about lifespan of EV batteries"

[ciaranob]

Ok. @Archimedes posted elsewhere that he believes Taycan's miles per kwh consumption reports are higher than his actuals.

WAY too verbose couple of examples of estimating SoH (and a bit circular in reasoning perhaps) from either your known Soh (OBDII or PPIWIS) or from total kWh used to charge your the car if known/recorded (my EVSE ChargePoint does a nice job of this).

The very last section might (or not) address your query?

___________________________________

New-battery usable kWh is 86 kWh (vs Porsche published 83.7) - See BaselIne Thread Post 1.

My latest measured Soh of 88%.

Using these values alone to estimate current available (degraded) kWh = 86 * 0.88 = 75 kWh usable

For completeness, if I use the Porsche pubished 83.7 usable kWh this = 73.7 kWh
____________________________


Now we can also determine Soh from total EVSE/DC charge-in in kWh but this method must also account for losses during the charging process /other effects.


Charge-in energy losses

My car’s average efficiency (from MyPorsche) = 36.7 kwh/100 mi over 7668 mi driven.

Total kWh less charging losses over 7668 miles = 3500.6/.367 = 2814.2 kWh
i.e. 686 kWh or 20% of charge-in is reported as losses (i.e. not used to propel the car forward).

Knowing this we can calculate Soh from total EVSE energy with 20% losses:

(kWh input * 0.8) /((end Soc-start Soc)/100))


Using this on a single charge event example from my car:

I put 51.9 kWh t recover 58% of my SoC from 27 to 85% Soc
So to calcualte SoH kWh (less losses) at an SoC of 100%:

(Charge-in less losses) / (Amount of SoC change/100) or as in this example:
(51.9 * 0.8) / (85-27 / 100) = 71.5 kWh SoH

Of course just one charge event.

If we use a more conservative 15% for losses (entirely speculative) = 76 kWh Soh.

Rather than use just one charge session, when I look at 21 successive AC home charges in 2023 (again using 20% losses).

I get an average SoH calculation of 77.6 kWh SoH

Compares well to the SoH derived from my OBDII/PIWIS Soh at 75 KWh

_____________________

So if I were to calculate an average efficiency for my car based off total charge-in and NOT take into account charge losses I’d have:

7668/3500.6 = 2.2 kWh per mile.

This is a lower value than the MyPorsche’s estimate which is ca. 2.7 kWh per mile.

However if I now calculate for losses I get:

7668/2814.2 = 2.72 miles per kWh matching the MyPorsche average efficiency.

Cheers, C.

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[whitex]

I'm sure you're correct that batteries will be cheaper if and when they're needed en masse, but, today, a Porsche OEM battery replacement costs $40k.

Worth noting that today the battery replacements are free, because all of them are covered under warranty. Tesla story was similar, $40K+ for replacement but all cars were under warranty. By the time first cars rolled off warranty, $22K IIRC, even cheaper today.

 

[Tooney]

WAY too verbose couple of examples of estimating SoH (and a bit circular in reasoning perhaps) from either your known Soh (OBDII or PPIWIS) or from total kWh used to charge your the car if known/recorded (my EVSE ChargePoint does a nice job of this).
The very last section might (or not) address your query?

Yes. Thank you. That does answer my question. Your calculations of consumption using data you collected from charging yield very similar results to average miles per kwh totals reported by the car and Porsche app.

 

[ben1]

Worth noting that today the battery replacements are free, because all of them are covered under warranty. Tesla story was similar, $40K+ for replacement but all cars were under warranty. By the time first cars rolled off warranty, $22K IIRC, even cheaper today.

Wouldn't it be cheaper on a Taycan because you can replace one module without replacing the whole battery pack ?

 

[BJCanadaMax]

other than outright failures (due to warranty issues - but still fractional) some data shows that batteries are _NOT_ the issue in overall long term EV ownership…

https://www.yahoo.com/news/researchers-surprising-discovery-lifespan-ev-110000330.html

I worry more about people hitting me now more than anything that can go wrong inside the car. I think that one issue is the car size. wonder if a 911 is smaller.

 

[Scandinavian]

Wouldn't it be cheaper on a Taycan because you can replace one module without replacing the whole battery pack ?

Well that depends on the labour costs. There is a lot of work to be done to replace modules. So perhaps there will be an exchange of batteries and all batteries repaired at one centre per country?

 

[whitex]

Wouldn't it be cheaper on a Taycan because you can replace one module without replacing the whole battery pack ?

Complicated answer. Tesla also has serviceable modules but started moving to non-serviceable, structural, super easy recyclable one. Any Tesla which needs a battery today would have modules, but the repair is to swap a battery for a refurbished one, and the old one goes in for refurbishing for the next customer. You do get "core" credit for your battery when trading it in, but it will still run you a few thousand out of warranty (probably depending how old/miles on the old battery, how many failed modules, etc).

The recyclable battery is supposedly even cheaper to replace and you always get a new one, since there are no refurbished ones. Your old, broken battery goes into a shredder from which comes out an ultra rich ore of materials used to build a new battery. Apparently the whole process is significantly cheaper because it does not involve heavy human labor building modular batteries (no need to manufacture independent modules then assemble them together - the recyclable one is essentially in a mold with glue) and no skilled labor diagnosing and refurbishing batteries., AND then recycling the battery at the end of life. Human labor is expensive. Robots work for cheap. This makes the batteries more eco friendly too as they are almost 100% recyclable. Customers are also happier to get a new battery instead of refurbished, should theirs fail.

 

[snstevens]

Complicated answer. Tesla also has serviceable modules but started moving to non-serviceable, structural, super easy recyclable one. Any Tesla which needs a battery today would have modules, but the repair is to swap a battery for a refurbished one, and the old one goes in for refurbishing for the next customer. You do get "core" credit for your battery when trading it in, but it will still run you a few thousand out of warranty (probably depending how old/miles on the old battery, how many failed modules, etc).

The recyclable battery is supposedly even cheaper to replace and you always get a new one, since there are no refurbished ones. Your old, broken battery goes into a shredder from which comes out an ultra rich ore of materials used to build a new battery. Apparently the whole process is significantly cheaper because it does not involve heavy human labor building modular batteries (no need to manufacture independent modules then assemble them together - the recyclable one is essentially in a mold with glue) and no skilled labor diagnosing and refurbishing batteries., AND then recycling the battery at the end of life. Human labor is expensive. Robots work for cheap. This makes the batteries more eco friendly too as they are almost 100% recyclable. Customers are also happier to get a new battery instead of refurbished, should theirs fail.

I read an article about this new recyclable battery technology earlier and it is very exciting. Not only is it cheap at the front-end (initial construction), and back-end (removal), it helps conserve resources. Sort of like what Apple is doing with MacBook enclosures (all recycled aluminum).

 

[whitex]

I read an article about this new recyclable battery technology earlier and it is very exciting. Not only is it cheap at the front-end (initial construction), and back-end (removal), it helps conserve resources. Sort of like what Apple is doing with MacBook enclosures (all recycled aluminum).

I cannot find the study, but saw one recently, that found that EV batteries made from recycled battery materials were apparently more robust (held up better, more cycles). It wasn't a Tesla recyclable battery study, just some university studying generic EV batteries, but I can see that making sense - materials twice refined, once from the ground, then again when they are recycled. Perhaps being in a battery for a while also helps the material?

 

[violuma]

wonder if a 911 is smaller.

Yes, but not by as much as I thought. Little over a foot longer, few inches wider, few inches taller.

 

[ben1]

I read an article about this new recyclable battery technology earlier and it is very exciting. Not only is it cheap at the front-end (initial construction), and back-end (removal), it helps conserve resources. Sort of like what Apple is doing with MacBook enclosures (all recycled aluminum).

It nice to see humans keep on finding solutions for their problems. We will surely succeed in solving the climate change and environmental problems.
I believe we can be optimistic.

 

[007]

It nice to see humans keep on finding solutions for their problems. We will surely succeed in solving the climate change and environmental problems.
I believe we can be optimistic.

I’m less optimistic looking at current climate and environmental changes, ecosystem breakdowns, and how quickly it’s happening. I think we’ll run out of time. All I see is doom and gloom for future generations.

 

[snstevens]

I’m less optimistic looking at current climate and environmental changes, ecosystem breakdowns, and how quickly it’s happening. I think we’ll run out of time. All I see is doom and gloom for future generations.

We didn’t get into this problem all at once, and we won’t get out of it all at once.

The level of creativity and innovation occurring now is astounding. There is always room for hope.

 

[007]

We didn’t get into this problem all at once, and we won’t get out of it all at once.

The level of creativity and innovation occurring now is astounding. There is always room for hope.

“The only true wisdom is in knowing you know nothing” (Socrates)… but data like the below does not give me much optimism.

 

[Capt Mike]

Take a look at this. Battery lives are better than we thought/hoped.

Researchers make surprising discovery about lifespan of EV batteries: ‘That was a shock’

https://finance.yahoo.com/news/rese...-110000330.html?.tsrc=daily_mail&uh_test=0_00

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