Long term battery life

[Megaton]

i’m seeing 270 mile range on my 22 premium extended awd with 55k miles. i’d call that between 0-3% degradation since i believe an ota opening the buffer should have had 278 mile range or 91 kwh.
charging to 80% before its below 20% on home level 2 and only dc fast charging for 1-2 road trips per year

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[RickMachE]

Range is not a measure of degradation...

 

[celestial_knight]

It has absolutely 0 problems making up dry technical “facts”, while providing you citations to papers that happen to not exist.

The AI chat bots first and foremost are tuned to tell you what response it thinks you want…you can generally get them to tell you anything.

Yes, exactly, that is why you tell it to triple check, and you cross reference

It is not surprising that in some ways they are akin to our own language generation, our left hemispheres. Overly verbally weighted people often are disposed to believe in just-so stories. In split brain studies the left just makes up whatever seems convenient

The famous “smart people are better at fooling themselves”, although I would consider them to be not really smart, since they lack understanding just like most, but spin more BS about it

 

[Teslaeata]

Range is not a measure of degradation...

Range can offer a gut feeling of how the battery’s doing but no more.

It can’t provide a component part of a calculation to work out SoH because there are so many other imponderables.

A more accurate method is required for an SoH rating.

As far as I know, the SoH measurement from the diagnostics is the most accurate though I still cross-check with measurements of individual cell voltages, Ah rating, module temperatures all which appear to actually support the diagnostic SoH rating and sort of contextualises my gut feeling based upon 120,000 miles of experience in all weathers & other conditions.

 

[0CO2]

Looking at the posts on this thread, there’s pretty good consistency across the range, which is reassuring.

I’ve got an early build ‘21 First Edition that initially I’d charge to 90% on L2, but in the past few years dropped that first to 85% and then 80%. I do perhaps 25-30 DC fast charges a year and around 6-8 L2 charges to 100% immediately before longer road trips. The car is garaged so not exposed to excessive heat very much.

With around 49k miles after nearly 5 years my OBD shows 7% degradation in SOH, so technically my “range” guesstimate should be around 251 miles.

What I see riding on 235 wide Pirelli Scorpions at west coast interstate driving speeds (fast and unfavorable to range), in cold fall conditions with a fair amount of mountain driving is over 200 miles actual.

DC charging on the road has improved dramatically to the extent there is no more range anxiety.

I just did a mid Oregon Coast Range run down to Reno, NV and back, and even in back of beyond places like Chemult in Central Oregon’s high desert there is an excellent GM branded DC charging station with a decent truck stop cafe.

The Rivian Adventure Network chargers in Shasta City, CA (also a 350 kW Chargepoint and two separate Supercharger stations there too) also were happy with my Mach-e (credit card accepted since Rivian Adventure Network not in Blue Oval plug and charge network), and of course Tesla Superchargers everywhere.

Tomorrow we drive up to Vancouver, British Columbia and let our US Mach-e sample some Canadian electrons.

Yes, road tripping nearly everywhere is no longer the hit or miss it was when I started driving electric in 2017 with that first Bolt and battery degradation even with NMC chemistry isn’t a big deal at all.

 

[Blue highway]

Most of that is nonsense, as is most AI stuff.

Ford designed the system to charge to 90%, which is basically 80% of the total battery.

50% is for 30 days or longer, not "at work".

Summer heat is irrelevant.

not nonsense at all...

Why 90%? because that is where the cell balancing kicks in for Ford batteries. You do need to balance the cells occasionally. And no, 90% is not 80%... you can see this with a scanner.

Shallow depth of discharge is better for cell longevity.

Storage at mid charge or a little less improves cell longevity.

high state of charge and high temps do reduce cell life. These are facts based on lots of research studies.

Quantitative Effects on Cycle Life

• At 30 °C, cycle life drops by ~20%; at 40 °C, by ~40%; and at 45 °C, by ~50% compared to operation at 20 °C. [large-battery.com]
• Long-term storage at 55 °C and 90% SOC can cause SEI thickness >300 nm and >20% conductivity loss after 36 months. [pubs.rsc.org]

Degradation Mechanisms at High DoD

• Mechanical Stress: Deep discharges cause large volume changes in electrodes, leading to particle cracking and loss of active material. [pubs.acs.org]
• Electrochemical Stress: Higher DoD increases SEI growth, electrolyte decomposition, and transition-metal dissolution, accelerating capacity fade. [mdpi.com]
• Microcracking in Ni-rich cathodes: Cycling at upper DoD limits (e.g., 60%) worsens microcracks, allowing electrolyte penetration and structural damage. [pubs.acs.org]

I'm not saying to worry about these things, but saying it is nonsense.... is nonsense.

 

[Guss]

OK, so, here we go……..Stangy’s an ER RWD Premium Feb ‘21 build, June ‘21 delivery just turned up 120,000 miles today with SoH recorded at 93.5%.

Been 93.5% for tens of thousands of miles.

Seems to have levelled out after 100k

Gotta be happy with that

Is your battery an LFP? And if so, do you charge it to 100% every time?

 

[Teslaeata]

Is your battery an LFP? And if so, do you charge it to 100% every time?

No. Not LFP.

 

[flapjake314]

i created a dataset with almost 200 datapoints...

https://www.macheforum.com/site/thr...-analytics-crowdsourced-data-add-yours.38065/

 

[GreaseMonkey]

i created a dataset with almost 200 datapoints...

https://www.macheforum.com/site/thr...-analytics-crowdsourced-data-add-yours.38065/

If I read your graphs, none have high R^2. Plus, SoH is formula based, not real. I wouldn’t read too much into any of it. We just don’t know enough.

 

[flapjake314]

If I read your graphs, none have high R^2. Plus, SoH is formula based, not real. I wouldn’t read too much into any of it. We just don’t know enough.

i posted it to answer the OP's question, i think it's probably the best indicator we have of battery degradation available

your points are of course valid but i'm not sure what you're suggesting as an alternative. it's a logical and valid question, where we have imperfect but non-zero data

 

[GreaseMonkey]

i posted it to answer the OP's question, i think it's probably the best indicator we have of battery degradation available

your points are of course valid but i'm not sure what you're suggesting as an alternative. it's a logical and valid question, where we have imperfect but non-zero data

Look, I appreciate you collecting the data. I might have even participated at one point (I don’t recall). But my issue is that data that is not indicative could lead you to incorrect conclusions. I think the only conclusion we can draw is that these factors do not provide a strong correlation and that we should look for other sources to answer the question. There are other studies of Teslas that provide more actual experience and none show that we should be concerned about battery health.

Five years in, we don’t have any concrete examples of battery issues with the Mach-E except for a faulty module here and there. That ought to be reassuring.

 

[Teslaeata]

SoH at 60mths since manufacture & 54mths since delivery is 93.5% still.

It may or may not be a definitive measure but is at least a really good comparator and “feels” about right with the range I’m getting compared with how the SoH has moved during service life to date.

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