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Variation in predicted kWh among online route planners

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Background: on Aug. 10, 2019, I'd like to make a trip from Cal Northern School of Law, Chico, CA, U.S.A., to the Tesla Supercharger at Donner Pass, CA, without charging en route. Question: can I make it with a reasonable margin for safety? I'm the original owner of the car, so I have some experience with road trips.

This is a 132.3 mi. trip with a net elevation change of 5,710 feet.

I used these online trip planners, listed in descending order of their age:
evtripplanner.com ("EVTP")
evtripping.com ("EVTG")
abetterrouteplanner.com ("ABRP")

Results in kWh used:
EVTP: 49.4
EVTG: 52.9
ABRP: 60.7

I tried to make the inputs as equal as possible among the three. Since EVTG uses seasonal weather data and reported a predicted en route temperature of 72.5F, I specified 73F in the other two. I specified a speed multiple of 1.14 or 114% , with the resulting average speeds (and driving times) of:
EVTP: 61.5 mph (2:09)
EVTG: 64.6 mph (2:03)
ABRP: 60.1 mph (2:12)

I figure I can begin the trip with a charge of 90-95%, or about 66-69 kWh. If ABRP's 61 kWh usage result is accurate I'm too chicken to make this trip without an off-route charge en route at Yuba City that would add about 45 min. total to the duration. But if usage of 53 kWh or better is accurate, I'd not charge en route.

I'm curious about the difference is results, and in particular the outlying difference of ABRP from the other two.
 
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Interesting. Do the others give a total trip Wh/Mi final figure? Obviously EVTG would have a lowes.

Do the other two give a "reference consumption" like ABRP? For example, the ABRP has 293 Whr/mi for performance and 247 for the 18" LR AWD Aero (and 263 for the 19"). All the temp, wind, extra cargo weight etc do nothing more than modify that number. You need a login to log into the others so I can't tell, but I'm wondering if their reference is close or the same? I even overwrite and use my historical Whr/Mi to get closer to the pin.

Now, I'm sure they might use different multipliers for the wind and rain, but that's after starting with a good reference. After you have the same reference, and then put in the real world multipliers, ABRP gives you a total trip Whr/mi. Looking at these things (the reference, and then changing the multipliers and seeing how the final trip Wh/Mil is affected) will give you a better idea how each one calculates total electricity use.

The reference for my 20" performance is 293. But when I put in 95 degrees, a 5 mile/hr headwind, it balloons to 321Wh/mi. After that's, it's a simple math calculation.
 
@brec,

That is quite a variance in predicted energy use. Have you also tried Tesla’s in-car nav to get its prediction for %SOC at arrival?

I also have an 85D, and it is a great road trip car. I use EV Trip Planner, and it has always worked well for me.

I would charge to 100% just before leaving, start out slowly (perhaps set cruise to speed limit), and watch the nav system’s SOC at arrival as I go. Usually (but not always) it will increase as I drive. If it gets too low, then I stop and charge. I check before leaving to see where the chargers are.

Good Luck,

GSP

PS. Leaving the battery sit at 100% speeds up degradation much more than charging to 100% and then discharging to 90% or less pretty quickly (under 1 hour or so).
 
Interesting. Do the others give a total trip Wh/Mi final figure? Obviously EVTG would have a lowes.

Do the other two give a "reference consumption" like ABRP? For example, the ABRP has 293 Whr/mi for performance and 247 for the 18" LR AWD Aero (and 263 for the 19"). All the temp, wind, extra cargo weight etc do nothing more than modify that number. You need a login to log into the others so I can't tell, but I'm wondering if their reference is close or the same? I even overwrite and use my historical Whr/Mi to get closer to the pin.

Now, I'm sure they might use different multipliers for the wind and rain, but that's after starting with a good reference. After you have the same reference, and then put in the real world multipliers, ABRP gives you a total trip Whr/mi. Looking at these things (the reference, and then changing the multipliers and seeing how the final trip Wh/Mil is affected) will give you a better idea how each one calculates total electricity use.

The reference for my 20" performance is 293. But when I put in 95 degrees, a 5 mile/hr headwind, it balloons to 321Wh/mi. After that's, it's a simple math calculation.

EVTP and EVTG (see original post for glossary) do not use reference consumption as an input. Not realizing, before your reply, the importance of that number to ABRP, I had left the input as what it originally downloaded from my car via Tesla. (At least I think that's the source.) That number is 324 Wh/mi "at 65 mph". I don't know how to get a good estimate of that number. I rarely drive at 65 mph, if that matters. The output from ABRP does not include kWh; I calculated the latter from its output of 459 Wh/mi and the distance of 132.3 mi.

Numbers I didn't mention in the original post were the same across planners to the extent possible. (10 mph over limit for EVTG instead of 114% of posted or average speed for the other two.)
 
@brec,

That is quite a variance in predicted energy use. Have you also tried Tesla’s in-car nav to get its prediction for %SOC at arrival?

I also have an 85D, and it is a great road trip car. I use EV Trip Planner, and it has always worked well for me.

I would charge to 100% just before leaving, start out slowly (perhaps set cruise to speed limit), and watch the nav system’s SOC at arrival as I go. Usually (but not always) it will increase as I drive. If it gets too low, then I stop and charge. I check before leaving to see where the chargers are.

Good Luck,

GSP

PS. Leaving the battery sit at 100% speeds up degradation much more than charging to 100% and then discharging to 90% or less pretty quickly (under 1 hour or so).

I don't know how to use the in-car nav to get a prediction from a distant starting point. At this writing I've never been to Chico, CA. I'm planning to arrive there on Aug. 9.

"Usually (but not always) [SOC at arrival] will increase as I drive." Usually for me it decreases fairly rapidly near the start of a leg, then perhaps increases a bit.

I don't leave the car sitting after a 100% charge, which I've only done perhaps three times. In Chico, my plan is to charge to or near 100% at the (new this week?) Supercharger before driving to the College of Law in the A.M, then departing for home in the early afternoon.
 
Great thread. I am interested as well and would throw in one other variable...the car’s navigation. I am travelling from Toronto to Long Island, NY soon and I to have gotten very different responses from each website and in some cases very different route suggestions.
 
I don't know how to use the in-car nav to get a prediction from a distant starting point. At this writing I've never been to Chico, CA. I'm planning to arrive there on Aug. 9....
.

Oops. Neither do I. I was thinking you were at Chico. Nevermind.

Leaving Chico with a warm Battery should help. The battery has more useable energy when warm: about 40-45 deg C.

If you are spending the night in Chico, finishing the charge just before you leave and pre-heating or cooling the cabin for 30 minutes or so will help warm the battery from grid power before you leave.

Range mode helps by warming the battery with waste heat from the motors and inverters.

GSP
 
I figure I can begin the trip with a charge of 90-95%, or about 66-69 kWh. If ABRP's 61 kWh usage result is accurate I'm too chicken to make this trip without an off-route charge en route at Yuba City that would add about 45 min. total to the duration. But if usage of 53 kWh or better is accurate, I'd not charge en route.

I assume that your preferred routing would be to take 99/149/70 to Marysville, then east on 20 to Interstate 80 to the Truckee Supercharger.

Yuba City's Supercharger is a detour, probably 5-7 minutes each way, depending upon traffic. Likely all you would need would be a 10-15 minute charge (even with 70% remaining in your battery) to ramp up your charge to 77-80%. I would suspect that would be an ample reserve to ease your anxiety!

I just wondered why you feel this detour would add 45 minutes. I think thirty minutes would be tops.

As others have said, once you arrive in Chico, set the navigation to the Truckee SC. See what the car determines. Also, start out easy on the speed to try to keep a few % in reserve as you climb. Also, I have found that taking it nice and easy on a lot of the ascents adds some reserve. The climb from Marysville to Grass Valley is gradual, and the climb from Nevada City to the junction with Interstate 80 is also gradual. You probably will not have much traffic on SR20 east of Nevada City, so perhaps use that leg to keep your speed a few MPH beneath the limit. You can always punch it once you hit Interstate 80.

Regardless, have a safe and fun journey!
 
In my experience, ABRP always predicts a higher energy usage than EVTP. There are several trip legs that I have taken and know that I can make easily that ABRP tells me that i need to slow down for, or cant make. There are features that ABRP has that make it nice for trip planning but I think EVTP is more accurate for energy usage. This experience is based on my P85+ staggered 21" and my 85D. Neither works particularly well for my P3D-, they all underestimate energy usage.
 
Thanks to all who've contributed. I could have made clearer that, while I do prefer shorter trip times to longer, a difference of 30-45min in total duration is not critical. My main question is implied by the thread title. Heretofore I've been using primarily EVTP for road trips, with acceptable prediction accuracy. There've been a few times I've slowed down at behest of the in-car nav, but not many.

Actually, I wasn't going to make this trip in the Tesla until I discovered that the new Chico Supercharger would be opening -- probably this coming week -- within walking distance of a Holiday Inn Express. There didn't seem to be any overnight destination charging -- Oxford Suites requires a two-night stay for my arrival day, and I need only one night.

Based on @cpa's experience, it looks like ABRP's predictions of energy usage are generally too high. It'd be interesting to know why.
 
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My road tripping method is use both EVTP and the on-board Tesla trip planner. The former is better for accounting for factors of wind, speed, weight, & HVAC, and show estimated energy consumption throughout each detailed segment. I use EVTP to estimate my overall travel time and to get an estimate of charging duration at the various SuC stations. Typically, I need a 30% buffer compared to the on-board trip planner because I want to drive faster and not get stuck behind left-lane hogs when trucks/trailers are ahead.

I use the on-board Energy graph to maintain a buffer between my projected miles and miles to destination; I pay more attention to this and decrease my speed if the projected SOC% at destination drops below 15%.
 
Have you tried the app EVTO?
I have found it to be pretty damn accurate
Im curious to know what it tells you
Digital Auto Guides | Bringing mobile technology to emerging automobiles.

The gui could use work but the app works

I just tried it. The output is graphs from which it's hard to get kWh consumption, but the SoC graph starts at 90% and declines to about 35%, indicating a usage of 55%. I figure my effective capacity is about 73 kWh, so 55% of that is 40 kWh, or about 302 Wh/mi., which seems implausibly low.

I prefer a web-based application, m'self.
 
I’ve messed around with trip planners for years and never found agreement among them..they are good for general information if you haven’t made the trip before, knowing your driving habits and car helps more. In my case I get about the same for driven miles as for miles consumed from battery. That makes it easy. Figure out a fudge factor if your road consumption is different. Just use common sense on altitude and weather corrections that might be needed, but almost all problems can be solved by slowing down. The car will tell you how much if you have the planner running.