Tesla's algorithms still out off whack

[Dutchie]

Last Monday we went on a rare road trip from the Vancouver Area to Vernon. It was cold and windy and we had to go over a pass (Coquihala Highway). Usually you can travel 400 km with the Tesla. The planner said we had to use the supercharger in Merrit which is about 250 km away.
We left with100% and I was confident as the planner said we would arrive with 28% remaining. We started driving and kept to the posted speed limit all the time. After a while the first warning came to stay below 120km/h to reach destination. No worries, as we were driving slower anyway. I checked and saw no that the planner said would arrive only with 5% remaining. What the heck, from 28% to 5%, ho come. Still not too worried as I did exactly what the car said. A warning came to remain below 90% to reach destination so - again I did.
About 30 km before the supercharger I saw that there would be nothing left in the battery! Now I got a bit worried. I had only 7% remaining.
Shortly after that I got the message to charge right away as I could not reach the destination. I only had 1% remaining. I was about 10 km away and going downhill. We just made it to the charger.

Apparently something is still off with the planner. I thought the planner would take into account the weather and road conditions. About 70% used of a 100kwh battery for 250 km suggest it does. I have a slack of about 30%, I do everything the planner tells to and keep within the posted speed limits and I still ended up driving with white knuckles. This was not nice..

 

[David29]

Last Monday we went on a rare road trip from the Vancouver Area to Vernon. It was cold and windy and we had to go over a pass (Coquihala Highway). Usually you can travel 400 km with the Tesla. The planner said we had to use the supercharger in Merrit which is about 250 km away.
We left with100% and I was confident as the planner said we would arrive with 28% remaining. We started driving and kept to the posted speed limit all the time. After a while the first warning came to stay below 120km/h to reach destination. No worries, as we were driving slower anyway. I checked and saw no that the planner said would arrive only with 5% remaining. What the heck, from 28% to 5%, ho come. Still not too worried as I did exactly what the car said. A warning came to remain below 90% to reach destination so - again I did.
About 30 km before the supercharger I saw that there would be nothing left in the battery! Now I got a bit worried. I had only 7% remaining.
Shortly after that I got the message to charge right away as I could not reach the destination. I only had 1% remaining. I was about 10 km away and going downhill. We just made it to the charger.

Apparently something is still off with the planner. I thought the planner would take into account the weather and road conditions. About 70% used of a 100kwh battery for 250 km suggest it does. I have a slack of about 30%, I do everything the planner tells to and keep within the posted speed limits and I still ended up driving with white knuckles. This was not nice..

Did the ambient temperature change much during your drive? If it did, that might account for at least some of the prediction error. As I understand it, the energy app uses the distance, expected speeds, energy use during your recent driving (5, 15 or 30 miles, per your setting) plus the expected elevation change to predict the energy consumption. Your previous driving is where the temperature effect comes in, i think. So, if the day was much colder than the previous trip, that might contribute to the calculation error. Just a guess...

 

[MP3Mike]

What did you have your climate controls set to? ("Excessive" heating can really kill your range.)

 

[Dutchie]

Did the ambient temperature change much during your drive? If it did, that might account for at least some of the prediction error. As I understand it, the energy app uses the distance, expected speeds, energy use during your recent driving (5, 15 or 30 miles, per your setting) plus the expected elevation change to predict the energy consumption. Your previous driving is where the temperature effect comes in, i think. So, if the day was much colder than the previous trip, that might contribute to the calculation error. Just a guess...

Well, yes in the mountains it was much colder of course. It went to -22°C while in the valley is was more like -3°C. As for the heater inside, we had it on normal heat but mainly used the seat heaters to have it nice

 

[ewoodrick]

I think that you probably just added two of the worse issues with an EV in the same trip, cold and mountains.
The cold is going to make the numbers lower, I tend to say drop the range by 30% and be happy if you get more.
Mountain? Well, there's the base energy needed to climb them, but reality is that the range computers just get too confused.

By the way, when you say "planner" which one are you talking about. The in car navigation, the Tesla website planner or one of the others.

 

[Dutchie]

I think that you probably just added two of the worse issues with an EV in the same trip, cold and mountains.
The cold is going to make the numbers lower, I tend to say drop the range by 30% and be happy if you get more.
Mountain? Well, there's the base energy needed to climb them, but reality is that the range computers just get too confused.

By the way, when you say "planner" which one are you talking about. The in car navigation, the Tesla website planner or one of the others.

I meant the navigation. But when you say cold and mountains don't these things always go hand-in hand this time of year? Strange thing is that the second leg of the trip went remarkably well. The trip from Merrit to Vernon is also mountainous. The remaining charge was almost to the dot. So there is something to it about ambient temperature of the last 30 km which navigation takes into account

 

[MP3Mike]

I meant the navigation. But when you say cold and mountains don't these things always go hand-in hand this time of year? Strange thing is that the second leg of the trip went remarkably well. The trip from Merrit to Bernon is also mountainous. The remains charge was almost to the dot. So there is something to it about ambient temperature of the last 30 km.

My understanding is that the planner takes into account the temperature of where you start, not the temperature of the places you travel through/to. (Though I thought I saw somewhere that that was going to change soon.) So if your starting temperature was warmer that might have thrown things off.

 

[kavyboy]

The in-car trip planner does not take weather into account. That includes rain, snow, wind, or temperature. It does account for elevation, which is why the trip graph is bumpy and not a straight-line graph even in the projected/remaining part.

 

[idoco]

I thought the planner would take into account the weather and road conditions.

tl;dr; NO!

Long version

The trip planner energy usage is based on distance, posted highway speeds, and elevation changes. Things that can significantly affect range (cold temperatures, headwinds, rain) are not part of the calculation.

Here's a picture from TeslaWinds browser app when we were headed west through Kansas. As you can see we were going 74mph but using energy equivalent to going 100mph! Since energy usage increases by roughly the square of the speed the additional energy requirement knocked down our range by 40-50%

Now for some tips.

1. When in doubt start off slower than you might normally travel. After 30 miles you can evaluate your energy usage and speed up (or slow down) based on the first 30 miles.

2. The energy consumption graph is your friend. I usually have it set for 30 miles and average projected range. This is the real time data you are looking for that takes into account cold, wind, and rain. The projected range is your remaining kWh divided by your average wH/mi for the last 30 miles. This is your range if you keep your current speed and conditions do not change. I find this very accurate in predicting remaining range.

 

[MP3Mike]

The in-car trip planner does not take weather into account.

The trip planner energy usage is based on distance, posted highway speeds, and elevation changes. Things that can significantly affect range (cold temperatures, headwinds, rain) are not part of the calculation.

From Tesla is now using more sophisticated algorithm with temperature to better predict range:

“The calculation is an estimate based on driving style (predicted speed, etc.) and environmental factors (elevation changes, weather, etc.).”

We asked Tesla about the change and the company says that they have always used ambient temperature around the car as part of the range prediction, but they are now also predicting the temperature changes around a planned route based on the elevation.

 

[kavyboy]

From Tesla is now using more sophisticated algorithm with temperature to better predict range:

Thanks for that info. I'm not sure how I missed that news, but it's good to know!

 

[Cirrus MS100D]

I’m not disagreeing to be disagreeable, only to counter that, once again, we found the complete opposite and it to be spot on on a 300 mile road trip to within a percent or two. This included a drive up into the mountains with the temps beginning at around 20F and ending at -4F. I was honestly amazed (again) how accurate it was from the times we unplugged til we got to the next destination.

Again, not sure if it’s just been good luck, but with 2 little ones, very late at night, heading into semi-rural Vermont, in sub-zero temps, I watch the range-o-meter and energy consumptipn like a hawk because running out of juice in that environment is NOT going to end well. I’m amazed at how accurate the trip planner has been, even in VERY extreme temps.

2 weeks ago in the extreme cold it accurately said we couldn’t make it home without an additional stop - This shocked me as we can almost certainly do the entire trip south NON stop, so adding TWO stops seemed insane. Sure enough, as we were approaching our “bail out or else” second stop, it was clear we weren’t going to make it. We only needed a 20 minute charge to safely buffer, but it said we’d roll in with X% and by damned we were X +/- 2% every time.

 

[MP3Mike]

I’m not disagreeing to be disagreeable, only to counter that, once again, we found the complete opposite and it to be spot on on a 300 mile road trip to within a percent or two. This included a drive up into the mountains with the temps beginning at around 20F and ending at -4F. I was honestly amazed (again) how accurate it was from the times we unplugged til we got to the next destination.

It could be a matter of different firmware versions. What version do you have?

@Dutchie what version is on your Tesla?

 

[idoco]

From Tesla is now using more sophisticated algorithm with temperature to better predict range:

Thanks for the information. Had not previously seen those quotes.

Although in the same article they quote, "...and the company says that they have always used ambient temperature around the car as part of the range prediction". Based on our 100,000 plus miles of driving, including lots of cold weather, I'm still not convinced.

Getting back to the OP, I still think that projected range on the consumption tab (30 mile, average) is going to give the most accurate real time data. This real time date accounts for temps, wind, speed, and elevation changes.

 

[idoco]

One other thing we need to be clear about is "which range meter" when talking about range. Are we talking about the range on the IC? Or projected range on the energy tab? Two different animals.

The range on the IC is a static calculation...basically remaining kWh divided by EPA rated consumption (~320wH/mi for an MX). The energy tab range is is a dynamic calculation...remaining kWh divided by recent consumption.

 

[ditzpro]

All of this should go away when charging stations are as ubiquitous as gas stations !
Range is still a really big deal when traveling ..

 

[Cirrus MS100D]

It could be a matter of different firmware versions. What version do you have?

@Dutchie what version is on your Tesla?

We’re still on 48.12.1

 

[DCGOO]

All of this should go away when charging stations are as ubiquitous as gas stations !

I don't think that will ever happen, because most people charge at home. No need.

 

[ditzpro]

I'm thinking about road trips only ...

 

[jerry33]

FWIW, for in city, the Ideal range seems to be the most accurate (about 1% plus or minus). For highway, the trip graph though it's a bit on the conservative side.