Buying a Model 3 prioritise age or mileage?

[AAKEE]

I don't doubt that batteries degrade over time and that there are a number of variable which impact the rate at which this occurs.

Is it not the case that 'calendar' aging happens whatever (we can't stop time!) and other factors - temperature, state of charge the battery is held at for prolonged periods, frequency of DC charge etc etc will compound this further to greater or lesser degrees?

Calendar aging = [Time x Temperature x SOC].

The rest, charging AC/DC and driving is cyclic aging.

What I was questioning was the assertion that a car with a low mileage will likely suffer more battery degradation than a similar aged car which have covered more miles? Is this indeed the case?

Not defenetive. But it is wrong to think that a low mileage car must have less degradation.

A battery “parked” at 80% or so has noticable calendar aging in normal temperatures.
A car driven normally or maybe more might spend more time at lower SOC which reduces calendar aging.

Having the car as much time as possible at or below 55% (60% for LG NMC, and 70% for LFP) will about cut the total degradation in half, or better.

This is my M3P after 2.5 years from new ( blue line). Except for a period (visible) where the BMS was off, the displsyed range was very high compared to other cars.
Last 100% charge was 492km range (driving to sell it), when the average was 460-465km. 507 km EPA, so the average range loss was more than double on the other cars.


This is my Plaid. Red markings by me. Still full range.
14 months since build date, 20K km

 

[GlynG]

I'm rather surprised that even people that bought Tesla, and no doubt did a bit of research prior to taking the plunge seem to have concerns of impending doom and a strong belief in the myths surrounding EVs, in particular premature failure of the battery.

100,000 or 120,000 miles / 8 years warranty isn't enough to reassure?

Doesn't the empirical evidence of the older 18650 batteries used in the Model S with the average degradation of 10 to 15% after 13 years not dispel thoughts of a limited lifespan?

The newer 2170 batteries used in the Model 3, the tweaks to the BMS, heating/cooling are all advances from the S and are likely to result in an astonishing overall battery life.
Of course premature failure of a battery pack is possible, just like a gearbox or engine failure with an ICE - but that's a gamble we all take when buying any car - and to be honest a new battery pack is around the same cost of a modern semi auto gearbox or engine replacement - but Is a complete failure probable? of course not.

With a range of circa 300 miles plus when new, how many people would be negatively impacted by having an old car - say 10 yrs old, that had a range of 200 miles? - and that would represent over 30% degradation.
Just to add context, prior to my Tesla I had a Focus Mk3 RS - brimmed the tank and range was 232 miles - according to the computer, reality was under 200 miles.

Three and a half years ago I bought my M3P - computer said 296 miles to 100% charge - today it says 295. (315 miles was Tesla's claim when new)

I struggle to comprehend the fascination on perceived lack of range with everything to do with the car, Fit mud flaps - will it reduce range, remove wheel trims - will it affect range etc etc etc. Now when did anyone ever ask the questions about impact on MPG with an ICE?

I have maybe 18 x 4amphr Dewalt batteries for my tools - inside they are simply 18650s - no thermal management at all, abused like F and most are over 8 years old - performing perfectly, no perceivable reduction in capacity, so I'm pretty happy to let my Tesla battery just get on with it - It'll all be fine.

 

[meavydev]

Care to take a picture like this, and post here?
View attachment 1049159
Should include SOC, average and calculated range on the same picture.
The selection fown right need to be visible and set at ”normal range”.

How about this from Tesla Mate?

New item by Shawn Fraser

photos.app.goo.gl

It doesn't quite match what the car says, but I can't be bothered to get the car out of the garage

 

[AAKEE]

How about this from Tesla Mate?

New item by Shawn Fraser

photos.app.goo.gl

It doesn't quite match what the car says, but I can't be bothered to get the car out of the garage

The term[usable] is very miss-used and misunderstood so not valid in this case.

Your picture probably shows the full capacity, normal “usable” was 74.3 kWh, from 77.8 kWh total.


Initial capacity was 77.8kWh ( the EPA tests indicated delivering even more than that).

You do not need to drive to get values from the energy graph like I showed.
Just go down and select that page and take a photo. Otherwise we can not use those values in your picture.

 

[meavydev]

The term[usable] is very miss-used and misunderstood so not valid in this case.

Your picture probably shows the full capacity, normal “usable” was 74.3 kWh, from 77.8 kWh total.


Initial capacity was 77.8kWh ( the EPA tests indicated delivering even more than that).

You do not need to drive to get values from the energy graph like I showed.
Just go down and select that page and take a photo. Otherwise we can not use those values in your picture.

What are you getting at that will show something different in the car? I said 305 miles from 310 miles when new and TM shows very slightly less and slightly more when new... This comes from the car in TM. I'm not saying capacities, as TM will be doing some calculation there.

 

[tgrobbo]

Didn’t the UK get LFP batteries for RWD in 2021? That's a hugely significant change lol.
Heat pump is also significant - it definitely increases your range.
As for older cars with low mileage - 100,000% I would wonder about how they’ve been stored. This is even more of a factor for ultra low mileage LFP cars, as a lot of them have been sitting around at 100% for nearly all their lives.
1,000,000% calendar aging is a factor on older cars - more so for LFP as that seems to be the only aging they do.
Another hugely significant factor is the battery and driveline warranty - the older the car, the closer it is to those two key warranties running out. (Assuming you hit the time limit well before the mileage limit)
EV’s are the opposite to ICE in that way - newness trumps low km I reckon, especially if you believe what many suspect - that a battery doing some miles and being used is healthier than one that isn’t.

 

[AAKEE]

What are you getting at that will show something different in the car? I said 305 miles from 310 miles when new and TM shows very slightly less and slightly more when new... This comes from the car in TM. I'm not saying capacities, as TM will be doing some calculation there.

Just do it, and show it. Its very easy

The energy graph is sourced from the BMS real data so this will take the uncertiness of third party app inconsistencies or doubts from these away. It is hard values, more non arguable than third party apps.

For one thing, that car will need to loose > 2% battery capacity before the range starts to drop.


Also, I know a little about the consistency in degradation/ calendar aging, which makes me wanna see the energy graph.

 

[AAKEE]

What are you getting at that will show something different in the car? I said 305 miles from 310 miles when new and TM shows very slightly less and slightly more when new... This comes from the car in TM. I'm not saying capacities, as TM will be doing some calculation there.

I would calculate your probable degradation to around 10%, if you did charge the car as most people do. Not knowing the exact charging behaviour and the average cell temp, I used the most used charging behaviour and average temp for your area.

That would put your car at around 70kWh, if you still is on the stock battery.

My 2019 M3P is very low mileage, and the rated battery range is still 305 miles from 310 when new. Only DC charged once and kept below 100% except for trips. So I don't agree

More or less all degradation comes from clendar aging so nit driving doesn’t really help.

 

[globetrotter77]

Hey all, Am really enjoying this thread and learning from it! As the OP, I feel like I should pop up here again and say thanks for all the advice/help! I just took delivery of a 2021 Model 3 LR and I absolutely love it!

It only as circa 16k miles on it - so the whole calendar age vs mileage debate is interesting. I haven't charged it to 100%, but pro-rata from the my own experiences yesterday (dual-carriageway and fast A roads - both hilly coz Devon and 14 degrees C-ish) its 100% range would be 300 miles for what that's worth. I'm pretty happy with that.

My only gripe is the windscreen wipers - I had heard they were annoying. They didn't come on automatically at all even though we had some quite hevy rain. And doing it manually is a bit of a faff. Also, when i engaged cruise it accelerated me unexpectedly to "max" speed, not current speed, which was unnerving! Have changed the setting now though.

Also, until my reg docs come through I can't use the app but hopefully that will be sorted soon.

Thoughts on CPU speed. Tbh, the navigation and main car functions are as fast or faster than a decent smart phone. The other stuff like browser and youtube is def a little laggy but I will hardly ever use it so don't care at all.

 

[GlynG]

My steam powered processor on my ancient 2020 is managing to keep up stunningly well displaying everything I want displayed as i drive.

Its a car, It shows a map, my speed and state of charge. Its maybe that i don't make any other demands of it - so the Atom is fine.
My car has never had any games running on screen
Never used the browser, never watched a film
Its never farted or done a lightshow or accessed anything in the toy box thingy folder. - I probably don't even know some of the things it could do - I may have once or twice viewed a sentry recording.
Dab radio or Spotify or navigation or cameras and obviously the settings is the limit with me.
Its my brain, its running slower than the Atom, so that's the limiting factor here.