Routing battery percentage

Routing battery percentage

Can someone please explain how my Tesla Model 3 calculates the battery percentage you will have when you arrive at your destination? Also why does a change?

Does it take into account your speed? The temperature outside? Your heater setting?

Bighorn | 7 december 2019

Takes into account elevation and average speeds on the route.
Does not factor climate usage or weather though it recalculates once it is exposed and can compare reality to anticipated consumption. It gets quite accurate by the 30 mile marker.

dvargo71 | 7 december 2019

Thanks I meant to clarify once you've been driving for a little bit. Seems to me it always creeps down driving on the freeway in cold weather but as you get closer steady and not just because of the shortened distance

Bighorn | 7 december 2019

Correct, it has recalculated with empiric data.

jowilson8888 | 7 december 2019

Why is the starting range figure in our Model 3 mid-range so inaccurate? We thought we had plenty of range to get to a town 82 miles away and back this week. The range at start showed well over 200 miles. When we arrived at our destination, we had only 95 miles left though. Had to scramble to find a destination charger - planned Supercharger station not yet built there - in order to make sure we could get back home safely in rush hour.

KAM6 | 7 december 2019

Speed, temperature, climate control, background apps (summon standby)

Bighorn | 7 december 2019

The miles shown are based on the EPA’s tests and you likely were using more energy for any variety of reasons—speed, heater, weather. The energy screen will give you a better sense of personal performance I.e. projected miles. Regardless, that venture was a risky proposition without good charging options.

dvargo71 | 7 december 2019

The energy screen I thought showed the same as the percentage I'm questioning?

KAM6 | 7 december 2019


dvargo71 | 7 december 2019

To be clear I'm NOT talking about the little battery that shows mileage. I am talking about the percentage that shows up at the end of the directions for your route.

FISHEV | 7 december 2019

"The range at start showed well over 200 miles. When we arrived at our destination, we had only 95 miles left though. Had to scramble to find a destination charger - planned Supercharger station not yet built there - in order to make sure we could get back home safely in rush hour."

You can't rely on the green "Range/PerCent" indicator. You need to look at the "Energy" graphic to see what your actual range is over last 30 miles.

It's cludgy and covers up the whole screen but you can check it and close it.

Winter time in areas that get cold, you can pretty much take 30% off the "Green Indicator" range and be close but look at the Energy graph which is fairly accurate. Just be aware the numbers can drop quickly. Look at 5/20/30 mile graphs to be sure.

KAM6 | 7 december 2019

Oh you are saying the percent from navigation? That should be more accurate but I believe it assumes you are going to go the speed limit. So if you are going 85 in a 70... There you go

dvargo71 | 7 december 2019

Yes I meant percentage on navigation. Today, for no apparent reason, it dropped from 20% to 10%. The temperature Rose slightly my speed was the same. Yesterday it worked perfectly today was different

KAM6 | 7 december 2019

It dropped after being parked or as you were sitting in it?

dvargo71 | 7 december 2019

While I was driving the drop everything was consistent speed temperature Etc

KAM6 | 7 december 2019

Hmm. Is it brand new?

dvargo71 | 7 december 2019

No August 2018. 16k miles

KAM6 | 7 december 2019

That is concerning. I haven't had that prediction be of by that much.

dvargo71 | 7 december 2019

The night before it was spot on.

dvargo71 | 8 december 2019

Is there any place Tesla spells out how they make the calculation?

bruryan | 8 december 2019

All the battery miles left indicators have lied to me. Or maybe I cheated on her, either way, I have come to understand she needs about 30% more than she thinks. Like any beautiful woman, it's best to accept.

When I picked up my new 3 the service center gave me about 70% charge*. I fretted internally, and asked if it was enough to get home."Oh yeah, you will have no problem". I pulled into my garage well into the yellow battery marker.
Elevation gain is not as up to the top level of consciousness in the Tesla noa, not in my world. In my driving elevation gains or losses speak in thousands, I will not stop charging until I'm at about 35% more than I "need". That is about right in my locale. Keeps me out of the yellow.
* 210 miles for a 110 mile trip~ 25 miles left.

FISHEV | 8 december 2019

"Is there any place Tesla spells out how they make the calculation?"

No and it has been changing update to update. Originally, May 2019 at least when I got mine, the green Rated Range indicator was whatever the car thought battery capacity was in kWh x base EPA rating. That's 4.13 miles per kWh, 310 miles for 75kWh battery.

Then "V10", 2019.32.x.x update that warranted its own special announcement (that months later won't go away on the app Messages) and Rated Range started to vary with driving (temp, speed, etc) as though Tesla were combining Estimated Range (which you can see with the Energy graphic) with Rated Range.

Rated range is still more optimistic than Estimated Range, by about 30% in the cold weather, but Rated keeps moving, prompting a lot of questions on battery degradation due to the induced variability in Rated Range.

Not sure what Nav uses, Rated, Estimated or a blend, for calculating per cent of battery left on arrival. Can probably figure it out by looking at the range number Nav produces when calculating a trip and see if it is closer to Rated Range or Estimated Range.

kevin_rf | 8 december 2019

It's gotten much better than it was when the Model 3 first shipped. There was a major update last winter that greatly improved the accuracy. I'm usually within a couple of percent of predicted after a long drive.

If you want to watch how it's preforming, pull up the trip energy graph.

Rikki-Tikki-Tavi | 8 december 2019

"FishEV:310 miles for 75kWh battery."
And yet two month ago Fish claimed we don't know real battery size bc Tesla doesn't tell us. Aren't you full of stinky sticks.

gparrot | 8 december 2019

WhiteWi, drop it. And get a life.

Rikki-Tikki-Tavi | 8 december 2019

As soon as Fishtroll moves on I will.

Bighorn | 8 december 2019

Nobody seems to be grasping the question about how the routIng updates, but the computer looks at what the computer predicted your efficiency would be with what actually happens and adjusts the arrival SOC accordingly. There need not be any special programming looking at specific metrics. For years, it’s provided very accurate numbers by 30 miles, but it’s quite good at half that. The initial predictions have gotten better for generic trips over the years, but the computer can not intuit headwinds or that you like an 80 degree car for your elderly aunt.
The car recommends charging to a point where your arrival SOC will be in the mid teens, so talk of going into the yellow, which happens at 20% is expected and not some undesirable outcome. It behooves you to arrive at those low SOCs as it maximizes the efficiency of recharging. I would disregard much of what has been written above, especially by the ill-informed resident troll. With over 300k miles on the road and a math obsession, you can take that to the bank.

dvargo71 | 8 december 2019

Thanks! And yes a lot are missing my question.

Joshan | 8 december 2019

Unfortunately on purpose dvargo71. A couple idiots on this forum think its funny to give out false information. Listen to Bighorn he is an expert on the topic.

dvargo71 | 8 december 2019

Thanks! Bighorn especially. I'm a civil Engineer and the math really interests me to!

Bighorn | 8 december 2019

I’m happy to go down that rabbit hole as long as you’re receptive to the message. It’s the ignorant arguers who I can’t abide.

jallred | 8 december 2019

For me the big question is whether the routing range estimate attempts to be non-causal.

If the function is causal then the output depends on present and past inputs only.
For instance, the function could be based on the current energy balance in the battery. You take the energy and multiply it by some number and you have your range in miles.

Then you can add in what the energy balance was some time ago (or distance ago) and use that old value to change your multiplier.

If you use a previous value of your range estimate in the function to calculate a new range estimate then your function is now using all previous data across all time (since you started collecting data and calculating).

Making it more complex, it could be that the function doesn't just use stored energy as a variable, but temperature, speed, and other independent variables. We don't know that they do this, but they might.

Finally, in an attempt to make it non-causal, they would look at where you are headed to gather more variables. For instance, if you are going from Phoenix to Flagstaff, the function could include the elevation gain that you will see during the trip. If you go the route you say you want to, what affect will that have on the calculated range.

Or they know you are headed to a SC and that you will precondition, will they account for that future preconditioning in your range calculation.

These expected conditions variables are things that we can do in our brain pretty easily, but it is harder to do in this function.

With or without it being non-causal, what importance do you place on present data over old data? Basically, they create some sort of filter to determine your "normal" driving conditions. Then they extend those normal conditions to determine your range.

Someone that drives in a consistent manner and will continue driving that way, in static environmental conditions will see the most accurate range predictions.

Sparky | 8 december 2019

As Kevin points out, the battery percentage remaining always equals the predicted SOC at the terminal position on the "Trip" graph. Good to look at if you're tight because it will show your SOC at any point on the route compared with the initial rated calculation. If you're dropping low you can adopt a strategy to get back to rated consumption before it's too late. Makes a fun game!