Road Trip Planning

[megant113]

@AxlxA I'm going to actually pay attention to the SoC calculations for my drive to/from work tomorrow. That should provide an interesting comparison: 35 miles at highway speeds, 70s with a slight tailwind in the AM, in the 100s with a stiff headwind in the afternoon. We'll see if the accuracy is different for the two trips.

 

[AxlxA]

@AxlxA I'm going to actually pay attention to the SoC calculations for my drive to/from work tomorrow. That should provide an interesting comparison: 35 miles at highway speeds, 70s with a slight tailwind in the AM, in the 100s with a stiff headwind in the afternoon. We'll see if the accuracy is different for the two trips.

Cool. My Tesla nav does a good job for my commute but I always try to hypermile it by staying in the slow lane and take the route with less elevation change. Also when going uphill, I let it slow way down if traffic flows allows and try not to waste electricity. My nav for my 26mi commute says 10% going to work and 12% going home(500ft elevation change overall) and I am able to get that down to 8% and 11% respectively.

 

[megant113]

And the results are in. The car expected me to use 12% on the way to work, and I used 14%. It again expected me to use 12% on the way home, and I used 16%. So extra A/C and a headwind did impact the accuracy, but it was still overly optimistic in better conditions in the morning. I feel like this confirms my guess that it's using rated efficiency, not actual.

 

[Effopec]

When I did a long trip with my kids I made a simple spreadsheet showing each charger along the route, distance from exit, restaurants, # stalls and speed. The restaurants column was key. I went through ABRP in the beginning, but then relied on the in car MCU unless I knew I wanted to deviate from it (i.e. wanted to stop at a charger that it says to skip because I wanted to eat there). I found that the guestimate for charge % remaining was within +/-2% even when driving 80-85 mph so after a few legs where it recommends to arrive at 20% I started dropping that down to 10% or even less. That is unless it looked like it may rain. Heavy rain will be a killer & I realized I needed to add 20-30% margin if I was going to run into that.

I really wish that when the nav is in trip mode that it indicated every supercharger along the route, or even anywhere on the screen. You can get in in the charger view, but then it takes you out of the navigation. Also, I like to watch the projected battery percent remaining as I drive to make sure I'm not sucking it down too fast, but in that view it is zoomed out so you don't see the details of the road & intersections. I've missed turns because of that.

 

[megant113]

I really wish that when the nav is in trip mode that it indicated every supercharger along the route, or even anywhere on the screen.

Yes! My husband and I were really confused by this at first, thinking maybe a Supercharger was offline.

 

[Feathermerchan]

If a supercharger goes offline, your car will tell you. It's happened to us. We took my 3 Performance but with 18" forged wheels as noted to Phila and back. We started charging so we would end with 20% at the next SC. On the way back we just used pretty much what the display said. Final leg was ~200 mi from Texarkana to Euless. It was about 46 deg and night. Some of that was 75 mph limit so people were driving 80. We watched the energy graph carefully knowing we could stop at Sulfur Springs or Dallas. We ended up at home in about 3 hours with about 20 miles left. We judiciously used the heat and speed to manage our final energy. It worked well. 3 hours is enough for a last leg of a two day trip.

 

[KenC]

We just got back yesterday, and I figured I'd post how it went down for posterity.

We stuck to the ABRP plan on the way to Colorado, and we used the in-car nav on the way back home. I think the in-car nav is better for our family because it tends to prefer fewer, longer stops. I think that works better for us, even if it is a few minutes slower over the course of the trip. There's a certain inertia to doing anything with kids, and all transitions take way longer than necessary. So once they're in the car, it's better to stay there, and same for making stops. While trying to follow the ABRP plan, we regularly stayed at a stop longer than required just to get everyone moving back towards the car.

As for the accuracy of the estimates:
I haven't given ABRP access to my Tesla account, because I'm just a little too paranoid about cybersecurity to do that. As such, the ABRP estimates were regularly too pessimistic with my actual car model selected. I switched to planning for aero wheels (263 Wh/mi reference consumption), and that seemed roughly correct.

The in-car nav was overly optimistic. By my guesstimate, we used 1% more than expected for every 10 minutes. So if we were doing a 2 hour leg, we needed an extra 12% charge, compared to what the car thought it needed to get to the next stop. I was regularly driving 10 over the speed limit, so I'm sure that was a contributing factor. I really wish I could tell the car to plan towards that.

All in all, the trip went well. Thanks to all who answered my initial questions!

ABRP is pessimistic by design. If you do register with ABRP, free, it allows you to calibrate your consumption. The reference consumption is conservative. For example the reference consumption for my LR-AWD is 263Wh/mile at 65mph, but when I let ABRP calibrate it for my vehicle, it came up as 235Wh/mile at 65mph. Seems low, but for my 350mile trip driven almost exclusively at 75 to 80mph, I averaged 265Wh/mile according to the car, so 235Wh/mi at 65mph seems fairly accurate.

 

[KenC]

I’m considering taking a long road trip in my LR AWD from Phoenix to the Orlando area but the 31hr drive turning into a 39 hour drive because of charges just doesn’t really seem too practical for me. I feel like anything over the 1200 mile mark just doesn’t seem worth it in these cars right now.

ABRP has me stopping every hour to hour and a half to charge which doesn’t seem right.

Try running a bunch of simulations. I just punched in Phoenix to Orlando at 115% of speed limit, so 75mph in a 65mph zone, etc. 27h 34min driving; 6hr charging; 33h 31mins total. There are lots of stops, but that's because charging in the 10% to 60% SOC range is the fastest, so ABRP optimizes for that.

You can go slower, and make fewer stops, but your overall trip time goes way up. My experience is that while driving faster, means more stops, you actually lower your overall trip time. Try running simulations.

Okay, just did. If you drive at 100% of speed limit, you can turn 17 stops into 15 stops, but your overall trip time increases from 33h 31mins to 36h 21mins. Instead of short 1 to 1.5hr legs, now you have some legs up to 3hrs, but you have to go slower and spend 3hrs more time traveling.

If you feel brave and like to drive 125% of the speed limit, ie 81mph in a 65mph speed limit zone, you can drop your overall trip time to 32h 20mins. An hour less than driving at 115%, so not as big a bang for your buck, as comparing 115% to 100%, where you save 3hrs.

 

[megant113]

ABRP is pessimistic by design.

With all the customization ABRP allows you to do, I'd prefer ABRP be accurate instead of pessimistic. I'm not willing to give my Tesla account password out to third parties, so I think I'll try to back-calculate my actual reference consumption.

 

[KenC]

With all the customization ABRP allows you to do, I'd prefer ABRP be accurate instead of pessimistic. I'm not willing to give my Tesla account password out to third parties, so I think I'll try to back-calculate my actual reference consumption.

Well, if ABRP were optimistic, then users run the risk of running out of watts. It's safer to err on the side of caution. Of course, try to calculate your consumption at 65mph and enter it manually, if you don't want to give away your credentials.