Navigation too conservative planning charging srops

[cypho]

I'm on my first road trip. The experience is fabulous overall, but there is one thing that just keeps driving me nuts.

The navigation algorithm insists that I should stop to charge much sooner than seems necessary. For example if I have 250 miles of rated range, and there are chargers in 150 miles and 200 miles, It will choose the charger at 150 miles.

Looking at the trip energy monitor, It seems to assume that I am going to get way worse than EPA rated efficiency when it does the calculation. It thinks I will get to that charger 150 miles away with only 10% charge. I suppose that's why it thinks I should stop there. But why does it assume I will get such worse efficiency than EPA rated? I tend to get a little better than EPA(with autopilot set to 5 over the speed limit).

After driving for 20 to 30 minutes it updates it's prediction says I will arrive at the charger with 35% battery, plenty to make it to the next stop, but it's still insist that I should stop as originally planned. And if I force it to recalculate, It goes back to assuming I will get terrible efficiency and still wants me to stop a lot sooner than I need to.

Is there any way to pick which chargers the navigator has me stopping at? Or any way to force the navigator to assume I will actually get the much more realistic (EPA rated) range?

 

[TexasEV]

Yes, navigate to the supercharger you want to stop at.

 

[swaltner]

You can force it to navigate directly to a specific Supercharger site by selecting that as the destination and then using the “remove charging stops” link if you don’t want to use the Trip Planner functions.

 

[Richt]

Congrats on your first road trip. We just completed a 5,000 mile one acids our MX and M3. What a blast!

YMMV but I also usual also see it is pessimistic. If you think about it this isn’t a bad thing. You sound like a very efficient driver (awesome!) but the system seems tuned for the worse case. You wouldn’t want to get stuck and not be able to make it.

The quick answer on a long trip is to just run the destination to the farther charger and see where you end up. FYI I usually leave a buffer there of say 15% as getting stuck sucks.

The longer answer is to use A Better Routeplanner and compare you actual vs predicted efficiency. At least for us this leaves the car bouncing between 15% and 65% and stopping every two hours. For us we fund the nav tends to make fewer longer stops (because charging up about 70% is so slow). That minimizes the total trip time. See for Tuning A Better Route Planner with TeslaFi — The Tong Family for the total nerd pack method

Final aside is you must be hyper efficient! I don’t understand how it estimates, but if it is predicting 10% then you are likely at 60% (150 miles/310mi assuming an AWD) but you only get to 35% wow that means you are only using 25% to go 150 miles do your real range is 600 miles. That’s amazing!

 

[bxr140]

This has been a ‘feature’ since trip planning (route planning?...I forget what it was initially called) was first introduced in maybe late 2014.

Short answer, ether deal with it or nav to your intended supercharger for each leg.

 

[cypho]

Final aside is you must be hyper efficient! I don’t understand how it estimates, but if it is predicting 10% then you are likely at 60% (150 miles/310mi assuming an AWD) but you only get to 35% wow that means you are only using 25% to go 150 miles do your real range is 600 miles. That’s amazing!

Not sure I follow your math. But no I'm not that efficient. I average around 230 Wh/Mi. EPA rated is around 242 I think. Problem is that the trip planner seems to assume I will do 275.

Attached is a typical example. Gray line is what the trip planner uses (I think) - says I will arrive with 4%). The colored line shows actual usage and the car's prediction of where I will be based on current usage (says I will arrive with 17%).

Difference is more than 10% and that is starting with half a tank. When I start with a full tank I can easily end up with more than a 20% difference.

 

[ewoodrick]

Yes, the car is definitely conservative. Would you fault it for being so. It doesn't like going much below something like 20%. Which does provide a buffer in case something isn't quite right at the next charger.
But, have you also planned biology breaks and eating with the Supercharger stops? That's the most important thing for better travelling. Don't stop for the car, stop for biology (and take care of the car at the same time)

 

[cypho]

Yes, the car is definitely conservative. Would you fault it for being so. It doesn't like going much below something like 20%. Which does provide a buffer in case something isn't quite right at the next charger.
But, have you also planned biology breaks and eating with the Supercharger stops? That's the most important thing for better travelling. Don't stop for the car, stop for biology (and take care of the car at the same time)

I agree conservative is better than optimistic. I guess really the problem is that it doesn't recalculate when it realizes that the assumption was wrong.

Probably needs to be fixed in both directions, if consumption is greater than expected it should recalculate and insert closer charger. And if consumption is less than expected it should recalculate to use a further one.

As far as biology goes, right now biology favors fewer longer stops.

 

[cpa]

I agree conservative is better than optimistic. I guess really the problem is that it doesn't recalculate when it realizes that the assumption was wrong.

Probably needs to be fixed in both directions, if consumption is greater than expected it should recalculate and insert closer charger. And if consumption is less than expected it should recalculate to use a further one.

As far as biology goes, right now biology favors fewer longer stops.

You are probably correct in that there is no recalculation once underway. The only reason that I can think of is that there may be potential weather-related issues on the second leg. So, yeah, you could easily drive the additional 60 miles to the next Supercharger and arrive with a "comfortable" 18% buffer when you are still 140 miles away. I acknowledge that this software cannot tell 75 degrees and calm from 42 degrees with a 25MPH head wind. They take the conservative approach in case someone like my wife is driving!

Just wait until you are older. Those biology breaks never looked so good even when 90 minutes apart!

 

[SigNC]

Don't worry, it won't be as conservative in the winter

 

[ewoodrick]

And while the car is conservative, there's no reason why you can't use this knowledge and change your plan. As other have mentioned, If you look where your charging options are, it's possible to pick a next location that's beyond the current chosen one. Just route to the specific charger. You may indeed start to get the "Stay below 65 to make it to your destination" messages. Over time you start to realize your driving habits and the car's recommendations. I tend to know that I can stay near the border line slow down messages and make it to the destination.

But everyone's driving habits are different, you've got to learn how you and the car best fit together.

 

[kavyboy]

I have cancelled the trip and then reentered the destination again while driving. That resets the trip meter and can sometimes alter the car's charging stops or even route. Normally, though, like other said, I just enter the desired SC stop as a destination.
My first road trip in 2015, it seemed much less pessimistic. I had read here to charge more than the car said I had to, so I did at my first stop. I wouldn't have come close to making the next stop if I hadn't. I think the new, more pessimistic scheduling is better.

 

[BioSehnsucht]

Clearly, you're just not driving fast enough