Why is range calculation not accurate?

[colt033]

My model 3 was in for repair recently and I had a model S loaner for a few days. The thing that struck my most, apart from the much milder brake regen, was how much more accurate the range of the model S was. So, for example, when I had 99 mile range and did a 27 mile trip, I ended up with 72 miles of range. My model 3, on the other hand, used 60 miles of range today for my 40 mile round trip commute.

I get that it's cold and I'm getting less range because I'm using the heating, but why doesn't the car take current driving conditions into account and change the range estimate (like an ICE car would do). The accurate range display in the S just felt so much better.

 

[Bouba]

My Model 3 is very accurate....perhaps you drive more cautiously in the ultra expensive Model S

 

[Jason71]

Where are you looking?
If you look in the trip section of the energy graph I find it is usually within a couple of % on most journeys.
The range on the main screen is just set to EPA which is useless. just set it to %. No idea what S is doing differently

 

[Kansalis]

I get that it's cold and I'm getting less range because I'm using the heating, but why doesn't the car take current driving conditions into account and change the range estimate (like an ICE car would do). The accurate range display in the S just felt so much better.

Because that's the way Tesla have designed the interface in the current incarnation. I don't think you'll get any better answer than that unfortunately.

The "range" displayed at the top of the main screen is simply the current battery percentage of the quoted US EPA range of the car. There is no efficiency calculation involved. The energy graph set to average over the last 30 miles should give a slightly better idea of the actual range.

 

[init6]

Literally millions (ok maybe not literally ) threads already in this forum for range questions. As @Jason71 says the energy graph is the most accurate. Setting the display to show miles leads to madness.

 

[colt033]

Where are you looking?
If you look in the trip section of the energy graph I find it is usually within a couple of % on most journeys.
The range on the main screen is just set to EPA which is useless. just set it to %. No idea what S is doing differently

Ah. Okay. That makes sense. I’m looking in the wrong place. I suppose the mileage display on the main screen gives an approximate indication, depending on how carefully you’re driving.

 

[Kansalis]

I suppose the mileage display on the main screen gives an approximate indication, depending on how carefully you’re driving.

Not really, it's an almost unattainable figure. Just set it to % as @Jason71 suggests & treat it a bit like your phone battery indicator.

 

[Adopado]

Ah. Okay. That makes sense. I’m looking in the wrong place. I suppose the mileage display on the main screen gives an approximate indication, depending on how carefully you’re driving.

It gives an ideal world, ideal driving mix, ideal temperature sort of estimate. You are correct in that it can be quite misleading. Some people stick with their battery showing miles but they need to make a mental allowance to relate it to any particular journey ... that's why many of us choose to set the battery to show percentage rather than miles. At least that is giving you some notion of reality i.e. if it says 50% then you have about 50% of your battery left! As has already been said use the energy graph for much more accurate information. I suggest that you put your destination in the navigation on the screen even if you know where you are going. This means that the graph will show your "trip" complete with predicted percentage at arrival. You will start to gauge how the consumption goes and how it varies by terrain, road type, ambient temperature etc.

 

[Bouba]

Ok...what if the difference is that the Model S that you borrowed hasn’t got Sentry Mode switched on

 

[Terry F]

On the M3 RWD LFP (but with only 400 driven miles so far) I have found that 1% = 2 miles is a good rule-of-thumb for me. I do 100-120 miles a week in shortish 5-20 mile journeys and use about 50% SoC to do this.

A very simple fix would be for Tesla to let you setup a conversion factor so that the mileage shown at top of screen (instead of % SoC) could be tuned to match your own power consumption experience, it would not be exact but probably a lot more useful.

 

[pgkevet]

Terrain, temperature, how you drive, traffic all effect the supposed range. I choose to display miles but mental arithmetic works either way %-miles-%.
Typical runs to the town south of me 12.5 miles uses more sparks than 15 miles to the north just because of terrain. Depending on time of year, I’ve varied from 270wh/m last 30 miles to 580wh/m in my S. over shorter journeys. On Motorways once everything is warmed up it usually runs at 310-350wh/m at 70mph weather dependant.

 

[kelvin 660]

A very simple fix would be for Tesla to let you setup a conversion factor so that the mileage shown at top of screen (instead of % SoC) could be tuned to match your own power consumption experience, it would not be exact but probably a lot more useful.

Or allow the range from the energy graph to be used as the range.

 

[Bouba]

Or allow the range from the energy graph to be used as the range.

I disagree with that....you have three energy graphs with different information on each...plus you have the energy battery showing three types of information....why would you want to remove any of that information?

 

[init6]

I disagree with that....you have three energy graphs with different information on each...plus you have the energy battery showing three types of information....why would you want to remove any of that information?

Allowing the range to be used does not necessarily mean removing any other options. As you have pointed out the past performance changes depending on the sample period, it's all a guess. So either allow you to choose which guess to display or IMHO just remove the mileage altogether.

 

[Adopado]

I disagree with that....you have three energy graphs with different information on each...plus you have the energy battery showing three types of information....why would you want to remove any of that information?

It could just work to reflect the percentage from the Energy Graph when you have set a destination in the navigation ... then it's reading a true and reasonably accurate countdown. Otherwise it could just work as it does now.

 

[Bouba]

The EPA estimation is based on a highway and city driving using an average of so many watts per mile...now my driving style, plus my mild climate, plus my destinations and local roads etc etc means that I (with my old man driving) match the EPA perfectly. If at the end of the day there is a discrepancy it is due entirely to Sentry Mode (man does that eat the juice ).
And in the six thousand plus kilometers that I have driven so far it has not once deviated from the EPA...mind you that does make you wonder what they were thinking when they made the WLTP