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Percent or Miles & Why?

Percent or Miles


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%
Miles really don't matter at all when you start treating the car like a phone or laptop. You wouldn't want your laptop or cell to display 'minutes remaining' because even if it did, it would be wrong more often than right as you change your usage.

Now, if it would display an estimate range number from the Energy screen, or give a max-min like the Bolt EV, I'd pick that over percentage.

As it is, rated miles is completely and utterly meaningless, especially in cold weather.
 
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Reactions: AlanSubie4Life
This. Tesla should just display both to end this discussion which has been going on for years.

Amen. Yup.

Amen.


the difference in ICE and EV....

the reason ICE gas gauges in % works so well, is because it's easy to fill up when you get low. you don't have to worry about how many miles you have left.
...

you can use math to figure it out, sure. but if you don't have to.....................

absolutely, 100% true. I have driven almost my entire life that way, never knowing total range or even mpg on most of my cars except the last two. It's a huge advantage with ICE cars, and I would never hold it against anyone that prefers ICE and the experience of: "I just drive it and fill it up when it gets low. I don't want to have to think about anything else."

I'm certain we will get there one day with EVs. But in the meantime, people can just pick what they like best.
 
It's not out of line with the slow decreases in performance and range from an ICE engine.

There's nothing in my original statement that said anything about that.

But in any case, that's largely a fallacy - modern vehicles in an operating condition that passes smog testing lose very little performance or range. My Subaru got the same mileage after 150k miles as it did when it was new (after correcting for seasonal variations due to gasoline ethanol content).

And even if there is some dropoff, it's far slower than a battery.

It's reasonable to expect 10% loss of capacity on an EV in the first 2-3 years of ownership. Range on an ICE vehicle in warranty is unlikely to change in any significant way over that same time period.
 
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Reactions: SSonnentag
That is what i like to see on phones...time remaining.

Except that time remaining varies drastically depending what you're doing.

So unless you only ever use your phone for one specific thing that'd be a useless measure.


If I'm surfing the web continuously on LTE at around 50% brightness it's going to last around 10.5 hours on a full charge.

For example if I'm playing video on my phone it's going to last around 11.5 hours on a full charge.

if I'm just talking on it as a phone continuously it's gonna last around 21 hours.

If I'm playing music continuously it's gonna last around 60 hours.

If I've just got it turned on doing nothing, basically standby mode, it's gonna last around 250 hours.


Which one should the phone display?


Ditto the car. The amount of km you can drive varies by how and under what conditions you're driving it.
 
I used to be very focused on miles and the degradation. In the end, there is nothing I can do about it. I recently switched to percent and find myself less stressed.

I will say that I am beyond shocked at the degradation at only 16,000 miles, at this rate my car may last to 100k.. my 100% is down in the mid 280s. , that’s 9-10% and I’m annoyed.

long story short, I’m on % now
 
I will say that I am beyond shocked at the degradation at only 16,000 miles, at this rate my car may last to 100k.. my 100% is down in the mid 280s. , that’s 9-10% and I’m annoyed.


You shouldn't be... (for one depending how you charge you might be some of that back re-calibrating the BMS- though it's only a display thing you haven't really "lost" whatever range comes back on the display in that case)

For another- 5-10% in the first year or two has been well known for a long time from Model S data.

And then...not much for years and year after.

Crowdsourced data showed relatively little loss beyond 10% until north of 186,000 miles.

Tesla battery degradation at less than 10% after over 160,000 miles, according to latest data - Electrek
 
Even the charge percentage is only an estimate.

There is nothing you can statically measure in a battery of unknown history that will tell you how much capacity it currently has remaining. The only way to measure a battery's capacity is to charge and/or discharge it at known rates of voltage and/or current and track the time it takes to fully charge or discharge. Even then, you still have to choose a definition of what it means for that particular battery to be at 100% or 0% charge.

What battery monitors typically do is start with some parameters about the battery (chemistry, etc.), and then capture charging and discharging activity since the last known full charge or full discharge, to determine how much capacity the battery "should" have at a point in time. So, it needs to know voltage/current into or out of the battery for how much time, since the last state of full charge or discharge. A monitor might also factor in other conditions, such as internal temperature of the battery, etc.

I guess you could assert that the Model 3 remaining range is less accurate than the charge percentage since (I'm pretty sure) it is just applying some estimate of expected watt-hours/mile to the estimated current state of charge (percentage), which does sort of add a layer of estimation. It's not a totally separate unrelated estimation.
 
(for one depending how you charge you might be some of that back re-calibrating the BMS- though it's only a display thing you haven't really "lost" whatever range comes back on the display in that case)

There's not actually a lot of evidence for this, other than a couple miles here and there (meaning 2-4, so insignificant relative to the loss).

In addition, I have people do timed duration charging experiments based on the known charging efficiency of the car, and the charging event takes the expected 10% less time to 100% for an SR car showing ~200 miles @100% vs. one that shows 220 miles @ 100%.

So there really does seem to be less energy to replace on these cars when they show reduced capacity.

But yes, it does seem to be true (so far) that the loss of capacity really slows down after the first year or so.
 
There's not actually a lot of evidence for this, other than a couple miles here and there (meaning 2-4, so insignificant relative to the loss).

There's about a billion anecdotes of folks getting 5-10 miles back this way. Saw at least 2 on here today.

Here's one for example:

Sheltering in Place - Charge or not

Guy went from 290 back up to 297-299 displayed range by doing this.



When you're only talking a loss of 20~25 miles in the first place (310 original to mid 280s in the case of the guy I was replying to) that's substantial...20-40% of the perceived "loss"
 
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Even the charge percentage is only an estimate.
[...]
I guess you could assert that the Model 3 remaining range is less accurate than the charge percentage since (I'm pretty sure) it is just applying some estimate of expected watt-hours/mile to the estimated current state of charge (percentage), which does sort of add a layer of estimation. [...]

It's worse than that - your assumption that the mileage is a real-time estimate is not correct. In Teslas, miles left are simply state of charge multiplied by a fixed constant which depends on the EPA range of the car you bought. At 100%, the miles left will always be the exact EPA range left.

The navigation feature does apply an estimate based on recent driving when it calculates charge remaining - but the actual range indicator itself doesn't (unlike most other cars which offer a "range" feature, including ICEs and EVs).

So I think of the miles left as a weird translation of the percentage left (in my 310-mile range car, miles are 3.1 * % charge left).

I find that a kind of silly measure of charge remaining, so choose to use percentage.
 
There's about a billion anecdotes of folks getting 5-10 miles back this way. Saw at least 2 on here today.

Here's one for example:

Sheltering in Place - Charge or not

Guy went from 290 back up to 297-299 displayed range by doing this.



When you're only talking a loss of 20~25 miles in the first place (310 original to mid 280s in the case of the guy I was replying to) that's substantial...20-40% of the perceived "loss"

I wouldn't be surprised if this was confounded by battery temperature. Some folks do the deep cycle and charge via a Supercharger, which will heat up your battery and allow it to report a higher charge. I've seen as much as 3% be "lost to cold" even without the snowflake symbol. Author of the linked comment is in Denver (which I was recently in and can confirm temperatures were cold enough for this).

Having recently effectively done the deep discharge and charge multiple times on the same roadtrip, my reported capacity did not change at all after accounting for temperature. That said, it's reporting 306mi @ 100% after nearly 13,000mi, so I'm not concerned yet.