Don't leave unless it shows 6% or more arrival

[Target]

Totally agree with the OP, also worth noting, if you are driving along and conditions (extreme head wind) turn against you it will say 5% long after it shouldn't really say 5% anymore. I had a situation over the winter where I hit a head wind (one that was blowing big rigs over) and it claimed 5% for long after I had committed (mentally) to not slowing down to make the farther of the two supercharging options. It carried on saying I could make it even though I was burning through the watt hours at a much higher pace than it was telling me to do.

It also seems to have an upper bound on energy consumption per mile when calculating the next leg, this was the only situation where I ever saw potential evidence of that upper bound. I don't have any data or awesome videos (good show OP) but just be aware if conditions are causing you to burn something close to 1kwh/mile on the highway don't be surprised if the car mis-estimates how much you need to make your next stop. Historically I have seen it do very well on long trips to adjust to my previous leg driving style and charge according to how much I used per mile. I am guessing that it looks at the recent leg and then charges based on that.

In my experience it will advise you to charge based on recent utilization per mile, however it can get fooled if that number is WAY to high as it won't assume those insane conditions will persist. If they do persist, you need to be aware and charge extra to accommodate. I burned through 57kwh in 61 miles, and it couldn't compensate for that insane rate of consumption like it normally does on long trips. I charged plenty extra to cover my next leg, and used it all!

This was late December 2018 so software as available at that time.


The summary is, while driving it won't go below 5% arrival SOC in normal conditions, so if you are using that to manage how fast you are going versus % remaining at arrival, don't count on it going below %5.

 

[joefee]

Since 2012, I've always added 30-50 miles (depending on conditions) of "range buffer" for all my road trips. Never had a problem range.

 

[Rownolds]

Great observation! Thanks for posting.
We put 45000 miles on our S in 2014, before SC'ers were everywhere. We did a lot of drafting off big rigs to stretch our range. Those who said it's a powerful technique are right. We once got 325 miles on a 265 mile range charge by drafting aggressively. Three observations: Drafting aggressively requires a lot of concentration, and this is exhausting; Drafting much less aggressively (3-5 car lengths) isn't too bad and is still very effective; you get a lot of little gravel dings all over the front surfaces from drafting.
Also, note that with adaptive cruise control set on 1,2,or 3, there's no concentration needed and it's very effective.

 

[BigTonyTones]

Great observation! Thanks for posting.
We put 45000 miles on our S in 2014, before SC'ers were everywhere. We did a lot of drafting off big rigs to stretch our range. Those who said it's a powerful technique are right. We once got 325 miles on a 265 mile range charge by drafting aggressively. Three observations: Drafting aggressively requires a lot of concentration, and this is exhausting; Drafting much less aggressively (3-5 car lengths) isn't too bad and is still very effective; you get a lot of little gravel dings all over the front surfaces from drafting.
Also, note that with adaptive cruise control set on 1,2,or 3, there's no concentration needed and it's very effective.

Drafting?
Does this mean staying behind big rigs in order to reduce air drag?

 

[BerTX]

All you people talking about drafting have obviously never had to replace a windshield... those things are expensive.

(and before you answer "nah, that's what insurance is for" -- you obviously don't know how insurance works.)

 

[DrGene]

If you are going to drive 75 to 80 mph its wise to assume the range is about 82% of the trip planner range.

Gene

 

[BigTonyTones]

If you are going to drive 75 to 80 mph its wise to assume the range is about 82% of the trip planner range.

Gene

What is nice about that evto trip planner is you can put what percentage above the speed limit you speed at lol. I recommend everyone giving it a try. There is a free version.
But the GUI is not the greatest

 

[TaylorSFGuy]

Hi Everyone. I come from my experience with two Nissan LEAFs. I was the first LEAF driver to 100,000 miles and the second (by a week) to 150,000 behind a taxi in the UK. I am so thrilled to have the Tesla range calculator. It is much more sophisticated. Taking into account changes in elevation out of the box was one of the open mouth moments.. The LEAF's range calculator was called the guessometer. I have run my M3 down below 5% and it did suggest that I keep the speed below 55 in order to reach home. I already had planned on pushing things and stayed off the highway.

In an EV, if you want to get the best range you can, you don't want to be the lead dog. Following anything, a truck or other vehicle can help you get where you want to go.

 

[EV-lutioin]

In my Model X, I always make sure there is 15% cushion... 20% if there is any wind or cold weather.

 

[Electric Denny]

Driving over 5 years and 200k miles in my S I learned a few things that are not documented. One of those things is the range prediction in the trip graph. It calculates what your battery percentage will be at your destination. An incredibly useful tool! It can me tricky to use, though as it automatically assumes a lower driving speed once it gets tight.

As you drive and it gets tight, the car will warn you by suggesting to stay below a certain speed to make it to your destination. It happens when the predicted arrival is 5%. At this point the car switches it's calculation to the suggested lower speed. We are all familiar with that.

What most people don't know is the same behavior is happening when you charge. It will actually start calculating with a slower speed. Once it's at 5% arrival or higher, it switches to normal speed. Not suddenly of course. It does so gradually.

It is a little difficult to explain, but below is a timelapse video that shows it really well. As you charge, the trip graph goes up. Once the arrival percentage hits 5% the calculation transitions from using a lower speed to normal speed. Note how it shows 5% arrival when the battery is at 81%. While it continues to charge it uses a faster and driving speed as a basis. The battery reaches 95% while the arrival is still at 5%. At this point, for the purpose of calculating the prediction, the normal driving speed is reached and now the arrival percentage goes up with the state of charge. If you watch the video it becomes very clear.

What does that mean? If you are charging on a road trip, never leave when arrival percentage is 5% or lower. Always wait for it to be at least 6% or higher to make sure the calculation is assuming normal driving speed. If you leave at 5% (or lower) you are going to have to do the entire trip with a reduced speed to barely make it.

Wow... This is incredibly useful info and wisdom. I've yet to even drive my car with 5% or less charge, but now I know what to expect when charging should I get down that low.

 

[Target]

Under those really high wind conditions I found the most difficult challenge was when the wind was not coming head on, but from 40 to 60 degrees off the nose of the car. You are scrubbing the tires to correct for the wind, which increases friction, and you can no longer draft directly behind a truck. You have to draft off their quarter. You can't really do that and allow traffic to flow normally and if wind direction is blowing towards the shoulder of the road nearest the truck then you may not be able to do it at all. I had that coming home in January, and it was a real "drag"

 

[derkan]

Thanks OP.
If it's telling you "please stay below 85mph to reach your destination" - geez how fast are you guys driving?
First month with my MX when I was clueless, I drove up to a supercharger with 2 miles of range remaining. 45 minutes before that it had already started warning me to stay below 65.... then 55... then 45 so it keeps adjusting the worse it gets. Out of fear, I ended up driving 25 on the freeway for the last stretch, with A/C turned off and windows closed.

 

[David99]

Thanks OP.
If it's telling you "please stay below 85mph to reach your destination" - geez how fast are you guys driving?

I'm taking the 5th on this one.

 

[mb300sd]

I've always used the estimated range from the energy graph based on the last 30 miles. Used to drive with it up all the time on v8 and found that projected range to be the most reliable. Haven't gone anywhere that I've needed to worry about range since I upgraded to v9 but I'm sure I'll miss being able to keep it up when I do.

 

[camthehombre]

I actually noticed this the other day when supercharging and had no idea why. I was very confused why one number (on the left) was raising, but the other (on the right) was stuck at 5%. Thank you! Makes a lot more sense now.

 

[Max*]

Interesting observation. I assumed it was a bug on Tesla's end, but you might be right.

At the point when the left number (your current SOC) is rising, but the right number (your SOC on arrival) is constant, if you restart the nav (i.e. cancel out of your destination, and plug in the same destination) sometimes the right number (your SOC on arrival) will go up. I've also had times when I had to slow down to reach my destination (I usually only leave a 5%-7% buffer); wondering now if the two are linked...

 

[RDoc]

All you people talking about drafting have obviously never had to replace a windshield... those things are expensive.

(and before you answer "nah, that's what insurance is for" -- you obviously don't know how insurance works.)

What are you talking about with insurance?

We've had 3 windshields replaced over the years, twice from rocks bouncing up from trucks, once from kids throwing stones (!). In all cases insurance replaced the windshield with no deductible and no impact on our rate.

 

[BerTX]

What are you talking about with insurance?

We've had 3 windshields replaced over the years, twice from rocks bouncing up from trucks, once from kids throwing stones (!). In all cases insurance replaced the windshield with no deductible and no impact on our rate.

Laws vary from state to state, but as with any law limiting insurance, it just spreads the increase over all customers instead of concentrating it on the one customer that made the claim. True, your rate did not go up to compensate the insurance company for the loss, but everybody in Mass had their insurance go up by a penny for each of your windshield replacements.

Insurance companies don't pay claims, they help you finance them.