Um. It's been known since the early times that the Tesla NAV software (never mind FSD, EAP, or what-all) attempts to get one to one's destination as Quickly As Possible. To that end, the software in the car and the Mothership (which knows which SC locations are crowded, which have 250 kW chargers, which have 120 kW chargers, and so on) play Major Software Games in order to minimize that time.
It's not just speed limits: At last gasp, the car software takes into account what speed one is driving at, whether there's a headwind (from weather information), whether one is going up and/or down hills, traffic information (like, traffic jams) and all that jazz.
In terms of range prognostication, as I'm sure most of you all know, from least accurate to most, it's:
- The range number/SOC (State Of Charge) meter at the top of the screen, leftish. My understanding is that this takes the SOC/amount of energy stored in the battery from the BMS and multiples it by the Manroney sticker value. This gives a range that only works if one is sitting in an EPA test facility. (No worries, sometimes one may as well be in something clearly like an EPA test facility.)
- On the Energy app, there's the Consumption Chart. Left axis has W-hr/mile; X axis has the last bunch of miles (range is selectable); and a little label on the right that has the instant or averaged range. In between there's a plot of energy usage over time. Go up a hill? Bigger usage per mile. Go down a hill? Less. Since it's an actual measure, it's more accurate.
- Also on the Energy app, there's a nifty plot that, under it, has other things. How one's driving (fast or slow) is affecting the calculated range. Same for weather, up and down hills, and a half dozen other things. There's even a bit in there for preheating before supercharging. There's also estimates of how much range one is going to get with all these factors taken into account, which makes the data here a bit hard to read, but more accurate than the above two.
- Finally, there's the Triple Number. Put in one's destination into the NAV and, in that square box at the bottom of the screen (or the one that has one's final destination in a multi-SC trip, gotten by hitting that "whole trip" button on the map screen) what time; with what charge; and how many miles it will be until one gets to one's intermediate or final stop. This little box has the whole kaboozie: Trips off the road to a SC, weather, driving habits, hills, etc., etc. It even includes battery degradation since new. It's ALL in there.
This beast hasn't really changed, except for additional parameters that Tesla puts in from time to time, since Teslas were launched. FSD isn't really involved: Drive without any of that, then you get what you get.
There's another tool out there, ABRP (A Better Route Planner) whose main claim to fame is that one can put down what charge one wants when one reaches one's final destination. Rather than some minimal value (like 10%) that the NAV tends to use.
FWIW, over the eclipse weekend, the SO an I took her MY from NJ to Dallas and back. It was interesting. In some cases, the NAV wanted us to hang out at a SC for 50 minutes until we got to +90% charge or so; in other cases, it was fifteen minutes to 70% charge and we were out of there. On the long charges, it's presumed that by doing so, we didn't have to foray off our direct route and got to skip an SC stop. In other cases, it's clear that, because the car charges the fastest when it's near empty, short stops with large amounts of energy dumped into the battery call for low SOC when one leaves for the next stop. So, yeah, I've seen the NAV and energy management in action.
Our main changes were involved in finding decent places to eat and/or sleep on the way. Still works.
On the road trips I make now I have plenty of SC around so kinda have forgotten those days and haven't seen this waning in a couple of years.
electrek.co
