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Energy / battery - why no adaptive range?

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Every car I’ve had with a trip computer, that estimates miles remaining, I’ve barely noticed the fuel gauge and always gone by the miles remaining view. I, and I think the vast majority of other users, understand that if, for example, the estimate is 50 miles remaining when you’ve been doing 50 mph, and you then decide to drive like you stole it, that the range will dynamically reduce.

My ICE car managed to lose 20 miles of predicted range whilst coasting downhill for less than 1 mile!!! The other point is that few of us have ever gone to empty in our ICE vehicles (sensibly!) ... we don't really know if we were actually running on fumes or still had several litres left in the tank when we filled up.
 
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My previous BMW ICE was miles off, typically forecast about 50% than it would achieve.

With the Model 3 my arrival percentage seems pretty good, maybe slightly pessimistic as I'm confident I'll make it and probably have a couple or percent more than originally forecast.
 
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However, TeslaFi does show a 'cold' battery rating, which if in force (its not in this screen shot), would have showed in blue along side the 76 above. The cold rating appears to be the % that the app displays, but I'm not entirely convinced that it is consistent. That will I believe affect the rated range, which is probably what you are seeing with cold/warm day differences.

To follow on from the earlier post.

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TeslaFi is now showing the 'cold' battery % mentioned above (75) . So whilst nominal battery remains at ~76%, usable battery is now reduced to ~75%

Note that rated range has reduced from 217.65 miles to 215.97 and estimated range reduced from 232.48 to 230.66.

Both (99.2%) are in line with the indicated '1%' reduction in battery capacity.
 
Plenty of other real design decisions to focus our attention on.
Dont get me wrong the inaccuracy doesnt bother me ive adapted quickly & only joined in to give my thoughts. I to use the % rather than range in miles.
I agree with VanillaAir_uk there are other issues major and minor we should focus on, getting AP working properly. My wife wont let me use AP when shes in the car with me. In fact she distrusts the car so much she wont drive it.
One minor change id like to see is to the navigation, more options such as:
Ignore motorways
Fastest route
Shortest route
Sensible route - one that doesnt take you to a major A road T junction (without lights) at rush hour expecting you yo turn right.
Learn route

But i digress so i will end here.
 
TeslaFi is now showing the 'cold' battery % mentioned above (75) . So whilst nominal battery remains at ~76%, usable battery is now reduced to ~75%

Worth mentioning for the uninitiated that as the battery warms on a longer journey you do get the "lost" percentage back. If you only ever drove short trips without enough time for the battery to warm then you would indeed be a couple of percent short.
 
To follow on from the earlier post.

View attachment 608041

TeslaFi is now showing the 'cold' battery % mentioned above (75) . So whilst nominal battery remains at ~76%, usable battery is now reduced to ~75%

Note that rated range has reduced from 217.65 miles to 215.97 and estimated range reduced from 232.48 to 230.66.

Both (99.2%) are in line with the indicated '1%' reduction in battery capacity.

The variation can be more than 1%. This plot from Teslamate shows just how much the range varies with temperature:

Projected range.jpg


Note the big dip where I've put the cursor, where the projected range using the battery level is roughly 17 miles below the projected range with the usable battery level. A short time later they are both pretty much the same, around the time the temperature rises to 15°C.
 
Exactly. But we seem to be alone in our view here! Maybe early adopters of EVs are already reconciled to the limitations and shortcomings, I am a new (late) adopter and I think they should have done a better job here and - if they had - a lot of the real world range anxiety problem would be resolved.

If you think Tesla is bad interms or range prediction, go and borrow a 24kWh Leaf, than take it out on to the nearest M way aiming to do 70mph in current weather.....Trust me it'll give you a new understanding of range anxiety and range predictions:).
 
Do any of you that use Teslafi, Teslamate etc have data to suggest that using AP (or FSD) has any significant impact on kWh? In my previous diesel car, using cruise control did reduce mpg compared to me driving the same route manually at the same speed.
 
Do any of you that use Teslafi, Teslamate etc have data to suggest that using AP (or FSD) has any significant impact on kWh? In my previous diesel car, using cruise control did reduce mpg compared to me driving the same route manually at the same speed.

That would indeed be interesting. I will be surprised if AP is as efficient as a human driver due to the tendency for AP to waste energy with unnecessary regen braking in various circumstances where a human would anticipate the situation and not lose the speed.
 
Treat it like an iPhone battery, keep it between 20 and 80%, charge to 80-90% when you need more, let it drift down into the 30-40-50 range when you don’t. Charge to 100 immediately before long journeys.

And forget about it. It’s so much cheaper and clearer than any diesel it just isn’t worth worrying about.

Ex-BMW owner (loads of them) here too. It took me about a week to lose the whole “where has my 600 miles range gone” thing. I thought it would be my main worry. Turns out finding opportunities to use the car is now my main worry as I appear to be heading for maybe 5k miles total driving this year instead of the 30k business miles plus personal driving that I used to do.

From next week the overnight Octopus Go charging time at 5p / KWh means my weekly charging will cost me about the same as a takeaway coffee. I used to buy about 15 of those a week so effectively from next week - other than supercharging - fuel is now free.

It’s mind-bendingly attractive to run one of these things compared to fossil fuels !
 
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Do any of you that use Teslafi, Teslamate etc have data to suggest that using AP (or FSD) has any significant impact on kWh? In my previous diesel car, using cruise control did reduce mpg compared to me driving the same route manually at the same speed.

Not yet, mainly because AP/TACC was just about unusable for me until the latest update (even now it seems to bang the brakes on at night for no apparent reason). I've routinely started using TACC again now it works, so should have some data before too long. I can pretty much say that all the data I have over the past year was without using AP/TACC, so much of the data from now on will probably be with TACC being used a fair bit of the time. I suspect it's TACC, rather than AP, that may make the most difference, if any, as it may be a bit steadier on the throttle than I am.
 
That would indeed be interesting. I will be surprised if AP is as efficient as a human driver due to the tendency for AP to waste energy with unnecessary regen braking in various circumstances where a human would anticipate the situation and not lose the speed.

On the other hand, humans are not good at keeping constant speed. Many drivers permanently swing between accelerating and decelerating. Recuperation helps, but its efficiency is 75%, not 100%.

Similarly, human drivers tend to swing left and right, rather than driving steadily in the lane. This also causes a little bit of energy loss on top of getting on passengers' nerves.

So I would expect that the autopilot saves energy. Whether that is significant is another question. "Significant" is not well defined.
 
Do any of you that use Teslafi, Teslamate etc have data to suggest that using AP (or FSD) has any significant impact on kWh? In my previous diesel car, using cruise control did reduce mpg compared to me driving the same route manually at the same speed.

The first approx 2/3 of this largely motorway drive during last Xmas break was done on NoA, the remainder full manual driving. I don't remember the exact split (although there is an obvious change in speed consistency), but note that the slope of the blue line remains pretty consistent throughout the whole drive. If anything, manual driving may have been slightly less efficient, but any difference doesn't look significant.

I posted this particular drive as I remember it well as 2/3 of the way through, we had an eventful aborted lane change so to keep the peace of the passengers, I reverted back to manual driving :eek:


upload_2020-11-14_19-22-39.png
 
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On the other hand, humans are not good at keeping constant speed. Many drivers permanently swing between accelerating and decelerating. Recuperation helps, but its efficiency is 75%, not 100%.

Similarly, human drivers tend to swing left and right, rather than driving steadily in the lane. This also causes a little bit of energy loss on top of getting on passengers' nerves.

So I would expect that the autopilot saves energy. Whether that is significant is another question. "Significant" is not well defined.

In the last few years before retirement, my employer introduced a policy where company car drivers had all cost for fuel deducted from their salaries & then business mileage was repaid based on the driver averaging within 15% of the manufacturers quoted mpg at a fixed ppm. That was virtually impossible to achieve of course.

As a high mileage driver I found myself losing up to £50 per month so I quickly became something of a ninja at maximising mpg, not just with speed (60-65 became the norm on motorways) but also smooth acceleration, anticipating stops & slowing to the point where traffic or lights would clear & I could carry momentum without actually stopping. I was adept at using downhill stretches to increase speed which could carry me part way up an ensuing rise. I even managed to occasionally 'make' on the deal and the company paid me - seeing the policy as a challenge to be beaten. Cruise control was an absolute no-no because it never tried to drive like this or achieved anywhere near the mpg I was able to average.

So that's why I have a suspicion that AP/TACC is probably going to burn through kWh's at a higher rate than most manual control & considerably more than the sort of driving described above (...not that I need to drive like that in a car with the motoring costs or performance of a Tesla!)
 
I'm with you. Have often applied similar ways of driving.

But the methods you describe are mostly unnecessary in a Tesla because of energy recuperation. I still think that TACC or Autopilot saves energy. You can still switch them off during the relatively short periods when you can save energy by using a particular maneuver.
 
Folks,

As a relative newcomer to Tesla, but as an engineer who understands the power dynamics, I am very curious about something and wonder if I am alone.

My Model S Long Range gives me a "miles" number for the equivalent of my fuel tank - but it is never right, it always over-states. Equally the energy burndown display when on a trip is never right. And when the car tells me I should make it home with 3% to spare, I already know I won't make it home! All of which is fine, I can choose to drive like a monk (which you need to do to achieve the indicated range) but I don't choose to.

What I am curious about is this. With such a smart car, with so much compute power available to it, with so many options and adjustments... why does the car not give me the chance to see a REAL range based on it's learned understanding of my driving style? I understand we all drive differently and I also understand that averages aren't always helpful but this car is monitoring my every move: steering inputs, break pressure, acceleration behaviour in different weather and road conditions, etc. I am 100% certain that, if they wanted to, Tesla could allow my car to give me a highly accurate range: "Alastair if you drive like you normally drive you have a real range of 265 miles not 320" for example; in the same vein the energy burndown chart could set the baseline for a trip to be what the car expects ME to achieve, rather than Manny the Monk.

I do get that Tesla maybe don't want to advertise that the real range is lower than the published, marketed range but unless we're stupid we all knew that before we got the car in the first place. Now it's nothing but annoying that the range is just wrong all the time and you have to manually calculate the offset. Ironically the range indicator on my diesel BMW was much more reliable!

Any thoughts?

Thanks

Alastair
With the Model S you have the option in the settings of rated range or typical range. The rated range is incredibly over optimistic (as in the M3). If you change to the typical miles setting you will find it a iot more realistic.
 
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I think the trip calculation is better then any car I have had!

Family holiday with 4 in car, every inch of storage full of luggage and 3 bikes on the tow bar in a SR+. I achieved 395wh/mile with an average speed on 60mph.

What amazed me is the car predicted this! I had driven 2 miles with the car loaded up to drop something at a friend before this journey. At this point I opened the trip graph up under the energy window and we pretty closely matched the predicated line. How did it know? All I can assume is in addition to looking at route and temp it a)new I had a 'trailer' as the lights are plugged in and b) calculated the weight based on the motor torque compared to the cars acceleration. I don't get that accuracy on my Audi A6 (though admittedly I dont need such accuracy with a large diesel tank).

So on one hand I was amazed on the accurate prediction. On the other hand realise long journeys with a bike rack on an SR+ will be short!

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