Charge! 18 days on the road by electric vehicle

charge, jack and susan goodwin

“If you don’t know where you are going, you’ll end up someplace else.” 

Yogi Berra

Planning and Finding Charge Stations

When we travel, Susan and I usually know where we want to go.  And we may or may not mind if we end up somewhere else. Still, we find that we get more out of our trips if we put some effort into planning them. Mostly, Susan plans them.

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For this trip, we decided to drive to Seattle.  Then we ended up someplace else.  A little bit of trip planning led us to choose the Rocky Mountains, particularly Yellowstone National Park, as the place we were going.

Next we had to decide which car to drive.  That was easy.  In May 2018, Susan took delivery on her Rear Wheel Drive (RWD) Tesla Model 3 with long-range battery.  I couldn’t stand having to switch back to my Internal Combustion Engine (ICE) car after driving hers.  So, using her referral number, I got an All Wheel Drive (AWD) Model 3.  Because it was a referral, I got a bonus of 6 months free Tesla Supercharging.  That meant we could make the trip with very little charge related cost for energy.

But first, we wanted to know which of the two would get better mileage on a charge, since hers has one motor and mine has two.  I set up a small, unscientific, and uncontrolled test.  Both cars were set identically with respect to energy consuming features (e.g., AC off).  Susan drove her RWD model just over 30 miles to work.  I followed in my AWD about 3 car lengths behind matching speed, acceleration, deceleration, lane changes, etc., as best as possible.  The route involved a twisty, hilly two-lane road for about 4 miles; a 4-lane highway for about 6 miles; and Interstate highways for about 23 miles.

Upon arriving at the destination, both cars had travelled a distance of 33.3 miles.  The RWD car averaged 212 Wh/mi (a measure of efficiency).  The AWD car averaged 214 Wh/mi.  Lower is better.  That very small difference could be noticeable over the expected 5000 miles of the trip, but it would be unlikely to affect the choice of stops to charge. So, the free supercharging won out.

Susan then took the lead on researching the various National Parks, attractions, and lodging that would define our route. I took the lead on researching routing and choices to charge.

The keys to the route evolved to become:

  • Visit friends in Denver
  • Rocky Mountain National Park
  • Grand Teton National Park
  • Yellowstone National Park
  • The Black Hills
  • Badlands National Park
  • Dayton, Ohio, to see the grandkids

Of course, there would be other things to fill the gaps.  (More on those as they arise in the trip discussion.)


I’ve usually trusted my gas gauge.  If I didn’t trust it, it was because experience told me not to trust it.  A quarter of a tank – time to look for a gas station.

This road trip would be without a gas gauge (or a gas station).  The gas gauge is a battery icon.  After twelve months with her car and six with mine, it was time to understand how reliable that icon is.  Plus, we needed to have some idea of where we would have to stop to charge since there aren’t six charging stations at every Interstate exit.  Susan asked, “Why not use the trip to see what it’s like to travel long distances in an Electric Vehicle (EV) and share the experience with others?”  Hence this blog in two parts.

Susan’s part of the blog is a travelogue, covering the beauty and excitement of the trip with day-to-day observations of EV travel.  This part is to try to capture the portion of trip planning related to energy use and management, and to answer some questions about the technical side of the trip.  Those questions include:

  • How much planning is appropriate, and which planning tools are most useful?
  • How well did the planning match real-world performance?
  • Did the plan come reasonably close to guidance from the car navigation system during the trip?
  • How well did the car’s own guidance track actual results?

Here we go.

The Route

The first concern in routing was “how far will we go on each day of the trip?”  We’ve done single-day trips that required charging, but this would be our first multi-day trip.  We’d need to know where we’d stop each night.  That meant that we’d need an idea of the highways we’d drive, the charging stops we’d make, and how long we’d be willing to spend in the car each day.  We needed to know when we’d arrive in key places where we expected difficulty in finding lodging (for example, in Yellowstone), and then build other stops around those.

Tesla has its own route planning app (Go Anywhere), but it is limited to just a few waypoints.  That makes it challenging to determine how to break up a multi-day trip.  A bit of research online, especially reading forums about EV websites and apps, led us to EV Trip Planner,, EV Hotels, PlugShare,, and others.  Each has its strengths, and each its frustrations.  (It’s also possible that I created some of my own frustrations with them.)

EV Trip Planner and showed promise, with the latter winning out for the major part of the planning.  It allowed me to enter specific information about the car and its energy usage, our expected travel speeds, and our preferred State of Charge (SoC) when stopping.  It also takes into account terrain, and can consider weather if you have reasonable information to enter.  It also allowed for a choice of type of DC fast charging.  (I chose Tesla Superchargers.)  Finally, it allowed some flexibility as to routing.

I was able to enter several key locations (Nashville; Denver; Jackson, WY; Billings, MT; Rapid City, SD; and Dayton, OH) to shape the route.  From there, we could see that we should plan about 2.5 days to get from Knoxville, TN, to Denver (including time for charging).  The only major thing we wanted to see en route was the Gateway Arch in St. Louis.  From Denver, we could take either one or two days to get to Jackson, WY.  Then one day to Yellowstone, one to Rapid City, two to Dayton, and one back to Knoxville.  We planned to spend two nights in Denver, two in Jackson, four in Yellowstone, and two in Rapid City.  We would end up adjusting those a bit as we continued planning.

The limitations of would show up when I chose route segments that required the use of something other than Tesla chargers.  In those cases, I turned to PlugShare and EV Hotels for information to refine our plans.  PlugShare can quickly show all of the known chargers in a particular area regardless of type.  It also has the benefit of allowing its users to check in and report their experience with those chargers.  That’s highly beneficial. 

Finally, I returned to EV Trip Planner to combine all the routing information as best as I could.  None of the route planners were capable of routing on the roads within the National Parks.  EV Trip Planner offered the means to shape the route as closely as possible to our desires.  It had the additional benefit of downloading an Excel file with all of the routing information.  More on that spreadsheet in a bit.  Here’s the route map:

Roadtrip map with charge stations included
The route taken.   © 2019, Jack Goodwin 
Route with charge stations included
Detail of the Grand Teton NP and Yellowstone Routes.  © 2019, Jack Goodwin 

EV Hotels is an app that provides information on the availability of charging stations at various hotels.  The information is crowd sourced and includes distance to chargers for hotels that do not offer their own.  Susan used this along with and Trip Advisor to plan our lodging.

It’s also worth noting that many RV parks have 240 volt 50 amp circuits at their campsites and are willing to work with EV owners needing a charge.

Back to the spreadsheet.  Since we planned to collect information about how the trip actually went as compared to plan, the Excel spreadsheet gave us a great start.  We wanted to know:

  • How far we travelled between stops;
  • State of charge at each stop;
  • How long we took to charge at each stop;
  • How much energy we used;
  • The price of gasoline;
  • And driving conditions (speed, weather, etc.)

I added some lines and columns to the spreadsheet for things we wanted to know, and hid lines and columns we didn’t need.  Then I printed it out so we could take notes at each stop.  The completed spreadsheet can be found in the download link below:

As mentioned, there were a few places that were a challenge to route using and EV Trip Planner.  Both wanted to route us through southern Wyoming mostly by Interstate, but we wanted to leave the Interstate at Rawlins, WY, to take a scenic by-way to Grand Teton National Park.  A full charge at the Rawlins Supercharger (SC) would not get us all the way to Jackson, WY.  Going via the Interstate would include another Supercharger and present no problems.  However, PlugShare identified a Level 2 charger in Lander, WY.  By including an overnight stop in Lander, we could add enough miles at that charger and be within reach of Jackson with miles to spare.

Since we would be based in Jackson for two nights, we planned to charge at the Superchargers there each night.

Yellowstone National Park is quite large – creating a need to charge multiple times over a multi-day visit.  While researching lodging, Susan found that there are Level 2 chargers within the park that are free for anyone to use.  They don’t show up if you just enter Yellowstone in PlugShare, but they do show up if you enter the specific lodges.  They are also mentioned on the Yellowstone National Park website, but the information lacks specifics.  The reservation agents for Xanterra (the company that manages the lodging) were very helpful.  There were two chargers each at the Old Faithful Snow Lodge and at Mammoth Hot Springs Lodge.  All had NEMA 14-50 plugs.  Other lodges in Yellowstone have chargers as well.  Once we confirmed our reservations at both of those lodges, we included them in our charging plans.  There are Tesla Superchargers in the town of West Yellowstone, MT.  We kept them in mind in case we needed another option, but did not plan to use them.

While making reservations for Chico Hot Springs Resort in Pray, MT, Susan asked if they had a 240 volt 50 amp electrical outlet where we might charge.  After checking with their maintenance staff, they said we could use their 220 volt outlet.  That was one more worry out of the way.

The various planning tools showed that we could expect several Tesla charging stations around the Black Hills – Spearfish, Custer, and Rapid City all have Superchargers.  So we left the details open for flexibility.

From there, the rest of the planning was easy, just instruct the Apps to head south at Madison, WI, rather than touring Chicago and its traffic.

With the planning done, it was time to travel.


Dwight Eisenhower said, “planning is everything, the plan is nothing.”  So, was that the case for our trip?  To better sort things out, let’s look at the trip in segments rather than days.

Anf if you’re interested in photographs from our trip, they are on our website at We’re including some Daily Discoveries – things that became apparent to us as we traveled.  Here’s the first:

Daily Discovery 1: If you’re thinking of tracking information like miles driven, energy consumption, etc., during your trip, develop your plan and tracking sheet well in advance.  Then, take the time to test it long enough to know that you’ll be capturing what you need, and that you can do it consistently.  We didn’t get the routine down until our second or third charging stop.

The Rockies are a long way away, so our first segment was basically getting from here to there by Interstate:  Knoxville, TN, to Denver, CO, in 2.5 days.  We drove through intermittent rain for the first day and a half with temperatures ranging from the low 40s to the low 70s.  The total distance was about 1,500 miles.  We had 13 stops planned for charging but actually only charged 11 times, all at Tesla Superchargers.  We expected to spend about 6.5 hours charging.  We actually spent 8 hours and 19 minutes.  The plan indicated that we should expect to get 310 Wh/mile (3.2 miles/kWh).  We actually did better, getting 274 Wh/mile (3.6 miles/kWh).  Why did we get these results?  Our charging times were extended at least twice while we had lunch during charging.  The better efficiency was probably because weather kept our speeds down.  We could have bypassed one charger (Limon, CO,) but we weren’t in a rush, and our printed plan copy erroneously showed 236.1 miles to the Denver SC, not 78.2 miles to the Lone Tree SC.

Daily Discovery 2: We had planned to get off to a fast start by driving directly to the Nashville (Brentwood), TN, Tesla Supercharger before charging.  Our route planners had suggested stopping at the Cookeville, TN, Supercharger after only 100 miles, then stopping again in Brentwood.  Once underway, we remembered that the Brentwood Supercharger is always busy (especially since it’s at the Tesla Showroom).  By stopping at Cookeville, we could avoid needing to charge in Nashville altogether.  That would save waiting for a charger and driving 12 miles out of our way to get there.  Lesson learned, don’t pass up an uncrowded Supercharger if the next one will likely be crowded.

Daily Discovery 3:Tesla’s navigation system led us to the wrong address for the Independence, MO, Supercharger – by about 6 miles.  PlugShare had the correct address.  We crosschecked charger addresses after that.

We spent two nights in Denver visiting friends.  While there, we took a day trip to the Garden of the Gods in Colorado Springs, and drove into the center of Denver for dinner one night.  We had not included driving around the Denver area in our planning because we wanted the flexibility to enjoy time with our friends according to their schedule.  Driving was a combination of Interstates and surface roads.  Distance was not recorded, but based on energy usage, we drove about 180 – 185 miles.  Charging time was 42 minutes at a Supercharger.  Energy consumption was 219 Wh/mile (4.6 miles/kWh).

Daily Discovery 4: By stopping at Superchargers outside metropolitan areas, we completely avoided situations where we had to wait to charge.  Tesla Superchargers typically have four to eight stations.  Stations are paired: 1A, 1B; 2A, 2B; etc.  Charging tends to be faster when not sharing a pair with another Tesla.  By avoiding metropolitan areas, we rarely had to share a pairing.

From Denver, we headed northward through Boulder to Rocky Mountain National Park, then on to Lander, WY, for the night.  We covered a distance of 465 miles, mostly on Interstates, but with some travel on park roads, and state and federal highways.  This was considerably more than the planned distance of 235 miles (which did not include RMNP).  Weather was partly to mostly cloudy with temperatures in the 70s and 80s.  We had lower temperatures at elevation in RMNP.  Our plan called for two stops to charge at Superchargers.  We added one charging stop in Lander, WY, at a public level 2 charger with a J1772 connector.  The price was $5 per hour.  The charger accepts credit cards.  Planned charging time for the segment was 1 hour 27 minutes.  Actual charging time was 3 hours.  Expected energy use was 238 Wh/mile (4.1 miles/kWh).  Actual use was 254 Wh/mile (3.9 miles/kWh).  We had lunch while charging in Loveland, CO, and we spent a full hour at the Lander charger, thus accounting for most of the difference in charging times.

Daily Discovery 5:The battery icon when set to miles reflects a calculation that appears to convert the percent of charge to miles based on the car’s rated energy usage (Wh/mi), not the real-world usage affected by weather, terrain, and driving style.  However, the navigation system seems to project SoC in percentage at the next charging point using a different formula.  Those predicted percentage numbers tended to be more accurate than the projected miles remaining as shown on the battery icon.  Knowing your typical energy use rates can increase your comfort with the car’s estimate of range.

Time to get scenic on the drive from Lander to Jackson, WY, with a visit to Grand Teton National Park.  The drive from Lander to Jackson had a planned distance of 160 miles. Based on our plan, we expected the mileage added in Lander would be more than sufficient to arrive in Jackson with energy to spare.  (Up to that point, we had been getting about 10% fewer miles per charge than our battery icon suggested.  The SoC leaving the Lander charger was 201 miles, about 25% more than we should need to get to the Jackson Supercharger.)   That’s when we discovered range anxiety.  Less than an hour out of Lander, the car started advising us to slow down if we hoped to reach our destination.  We were gaining elevation (about 4,300 feet) and losing warm air.  Even with regenerative braking on a 2,900-foot descent, the car continued its warnings. 

PlugShare had identified the Jackson Lake Gas Station (about 5 miles out of our way) as having a NEMA 14-50 outlet.  We took the chance and headed there to add a few miles, but the station had not opened for the season, and the person there was reluctant to let us plug up.  So we drove slowly (25 – 30 mph) down to Jackson. As we got closer, it became apparent that we would arrive with no problem.  In fact, our SoC upon arrival was 19 miles. Unfortunately, the time it took for the detour and slow drive cost us the opportunity to explore parts of GTNP while the weather was still good.  The actual distance for this multi-day segment was 350 miles including driving in Grand Teton.  Travel was on US highways and national park roads with frequent stops.  Ninety miles of that was touring GTNP.  The GTNP mileage was deliberately left out of the planning to be flexible in the park.  Weather was mostly cloudy with some rain on the second day. Temperatures were in the 50s and 60s.  Our plan called for one charging at Jackson for 1 hour and 14 minutes, but did not account for the driving that we would do the next day.  We actually charged three times for a total of 2 hours and 36 minutes total.  Expected energy use was 211 Wh/mile (4.7 miles/kWh).  That expected use was based on travel from Rawlins, WY, to Jackson, WY, not from Lander to Jackson.  Actual use was 231 Wh/mile (4.3 miles/kWh).

Daily Discovery 6: Our first non-Tesla charging was in Lander, WY, at a Level 2 charger.  Planning had indicated that we could drive from the Rawlins, WY, Supercharger via Lander, to the Jackson, WY, Supercharger on a full charge of 309 miles and arrive with only a few electrons left.  For peace of mind, we chose to add 40 miles at the Level 2 charger in Lander so that we could arrive with charge to spare.  Our projection suggested that, based on trip experience to date, we were using about 10% more battery icon mileage than actual road distance.  That 40 miles gave us 20% more battery icon mileage than actual mileage.  However, terrain and temperature worked against us.  About a third of the way from Lander to Jackson, the navigation system began warning us to slow down in order to reach our destination.  We did make it to Jackson, but not without a touch of range anxiety.  That range anxiety could have been avoided by adding another 40 miles at Lander (inconvenient, but doable).

We headed for Yellowstone National Park for four days, then on to Chico Hot Springs Resort in Pray, MT.  The route took us straight north from Jackson to Yellowstone.  In Yellowstone, we drove various loops and roads before heading out the North Entrance for Pray.  We followed US highways and national park roads at speeds typically from 30 – 50 mph.  Over the four days, weather varied from mostly cloudy to partly cloudy to snow to cloudy again.  Temperatures varied from the low 30s to the mid 40s.  We expected to charge twice using the Level 2 chargers at Old Faithful Snow Lodge, once or twice using the Level 2 chargers at Mammoth Hot Springs, and once using the 220 volt outlet at Chico Hot Springs.  We actually charged 4 times – twice at the OFSL, once at MHS, and once at Chico.  When we got to Chico, we discovered that we did not have the right adapter, so we charged on the 110 volt wall outlet.  Fortunately, we only needed to add a few miles for peace of mind.  All charging was done overnight.  Because we could not enter the Yellowstone NP roads into EV Trip Planner, we had no estimates for mileage or energy use.  Our sightseeing mileage totaled 446 miles.  Actual energy use was 233 Wh/mile (4.3 miles/kWh).

Daily Discovery 7: PlugShare user check-ins provided very helpful information as we approached charging stops.  It was not unusual to read that users have experienced different charging speeds at different stations at the same Supercharger.  That enabled us to select the station most likely to provide 120 – 140 kW charging.  User check-ins also noted which (if any) stations were out of service.  User check-ins also helped with actually finding the chargers in their hiding places, especially in Yellowstone.

Daily Discovery 8: When calling about reservations, Susan asked the folks at Chico Hot Springs Resort if they had a 240 volt 50 amp outlet where we could charge overnight.  Their maintenance people said we could use the 220 volt outlet in their maintenance building, and they made a note in our reservation.  We forgot to ask what kind of plug it took.  Our adapter was a NEMA 14-50.  Their outlet was NEMA 10-30P.  (Yes, I had to look that up.)  We charged that night on a 110-volt wall outlet.  The lesson would be, when planning to use an available outlet of unfamiliar provenance, request a photo of a plug that fits their outlet.  That way, you can be sure to have an adapter that fits.

Leaving Chico, we began a long day of covering distance, with just two key sightseeing side trips – Little Big Horn Battlefield National Monument and Devil’s Tower National Monument.   We took the US highway a few miles north to pick up the Interstate. From there it was mostly Interstate with about 50 miles of state roads in Wyoming.  Planned distance was 374 miles, and actual was 387.  Speeds varied from 30 – 50 on highways to 70 – 85 on Interstates.  Weather was overcast with occasional light snow late in the day.  Temperatures ranged from the low 30s to the low 50s.  Our planning notes said that we’d need 65 kWh in Billings, MT.  But that was based on the assumption that we had last charged in Jackson, WY.  As a result, the projected energy use for this segment is not comparable to actual use.  We planned 3 charging stops (all Superchargers) for a total of 1 hour and 24 minutes.  We actually stopped 3 times for a total of 1 hour and 39 minutes.  Planned energy consumption was 252 Wh/mile (4.0 miles/kWh), but as noted, this is not comparable to our actual use for this segment.  Actual use was 305 Wh/mile (3.3 miles/kWh).  After all, Interstate speed limits in Montana and Wyoming are 80 mph.

The following day was devoted to sightseeing in the Black Hills.  That meant driving on federal and state highways and state park roads with numerous stops.  Our planned distance for the day was 276 miles.  Actual distance was 334 miles ending the day in Wall, SD.  Driving speeds varied from 20 – 50 mph.  We had variable cloudiness with temperatures in the 40s and 50s.  We planned to charge twice at Superchargers for a total planned time of 1 hour and 23 minutes.  Our actual time for the two chargings was 2 hours and 16 minutes, but we had dinner while we charged the second time.  Expected energy use was 217 Wh/mile (4.6 miles/kWh).  Actual use was 260 Wh/mile (3.8 miles/kWh).

With the turn to the East, it felt like we were headed home.  Our route for this segment followed Interstates across South Dakota, Minnesota, and Wisconsin, with a bit of sightseeing before we left South Dakota.  That included surface roads in Badlands National Park.  The planned distance was 633 miles, actual was 676 miles.  Since the objective was to cover distance, driving speeds on the Interstates were 75 – 80 mph.  Weather was partly cloudy, windy early, with temperatures in the upper 60s to upper 70s.  Six charging stops were planned (all Superchargers) for a total charging time of 3 hours.  We actually stopped five times for a total of 3 hours and 8 minutes.  Expected energy use was 329 Wh/mile (3.0 miles/kWh) based on high estimates of average speed.  Actual use was 277 Wh/mile (3.6 miles/kWh).  Most likely, favorable weather and mostly Interstate travel produced the better energy use.

Daily Discovery 9: When we could coordinate our charging stops with our meal breaks, we could easily add significantly more mileage than needed to get to the next charger.  Even when we could not, we typically took the time to charge to about 80% SoC.

Daily Discovery 10: Long road trips lead to dirty cars.  We use a two-bucket system when we wash our cars at home.  One bucket has a single no-rinse cleaning concentrate mixed with water, and the other has clean water to rinse the sponge.  Had we taken our buckets, sponges, and micro fiber towels, we could have washed the car every few days while we charged it.

Our next travel day would take us to see the grandkids.  We followed Interstates all the way from Wisconsin south into Illinois and across to Dayton, OH.  Planned distance was 554 miles.  Actual was 528 miles.  This was all about covering distance, so our driving speeds were 75 – 80 mph.  Weather was partly to mostly cloudy with temperatures in the lower 70s to upper 80s.  Five stops were planned for a total charging time of 2 hours and 23 minutes.  (All Superchargers.)  We actually made only four stops, but still charged for 2 hours and 22 minutes.  Planned energy use was 294 Wh/mile (3.4 miles/kWh).  Actual use was 295 Wh/mile (3.4 miles/kWh).  In Dayton, we took a break for a couple of days.

The sprint home was straight down the Interstates.  The plan was 361 miles.  The actual distance was 404 miles.  Again we were driving 70 – 85 mph.  Weather was partly cloudy with temps in the mid 80s to low 90s.  There were 3 planned Supercharger stops for a total of 1 hour and 32 minutes.  We chose to only stop twice for a total of 1 hour and 39 minutes.  Projected energy use was 302 Wh/mile (3.3 miles/kWh).  Actual use was 270 Wh/mile (3.7 miles/kWh).


Earlier in this blog, we raised four questions.  Now it’s time to see if we have answers.

How much planning is appropriate, and which planning tools are most useful?

The easy answer is “that’s up to you.”  Our trip required that we be in Yellowstone on certain dates because that was when we could get reservations at the lodges.  We also had some constraints on when we would start and when we would return home.  That meant that we needed a reasonably good sense of driving and charging times would take us each day.  Since this was our first major cross-country trip by EV, we used the driving and charging times from and EV Trip Planner to get a sense of where each day would end (plus or minus a charger’s distance).  We preferred ten-hour days, but we had some that were a good bit longer.

We also needed to recognize when we would not have access to Tesla Superchargers so that we could make adjustments.  PlugShare proved to be indispensible for that purpose. 

The Tesla Model 3 navigation system provided our real-time guidance throughout the trip, enabling us to decide to skip or add a charger.  The PlugShare app served as an excellent real-time backup planner while on the road.

How well did the planning match real-world performance?

Perhaps one of the best ways to look at this is by comparing actual State of Charge to what the planning tools led us to expect.  This first chart shows the planned SoC upon arrival at each charging stop in blue and the actual in red.

Arrival charge

In setting up evtripplanner (the source of the Excel spreadsheet data), I specified that SoC should be no lower that 20% upon arrival at each charging station.  The program accommodated that by setting RM In (Remaining Miles upon arrival) at 58 for all but the first planned stop.  Thus, the flat blue line.  The gaps in the blue line are stops that weren’t in the original plan.  The gaps in the red line are places where we bypassed planned charging stations, typically when we had sufficient miles remaining to go to the next station.  Those mostly occurred when evtripplanner wasn’t able to show the routes we wanted (e.g., roads within Yellowstone National Park) or when we had no specific route planned (as with our two night stay in Denver).

There are five times that the red line (Actual SoC In) drops below the blue line (Planned SoC In).  Those could reasonably be identified as opportunities for range anxiety since the SoC was below 20% (~58 miles according to evtripplanner, ~62 miles per the stated range of 310 miles per charge).  In fact, we tended to only worry when the navigation system projected a SoC of 5% for arrival at our next stop, and only the first stop in Jackson, WY, was true range anxiety.  Through careful energy management the last 30 miles, we arrived with 19 miles remaining.

Now, let’s turn to SoC upon departing from each charging station.  As before, the blue line shows the planned SoC, and the red line shows the actual SoC.

Departure charge

Evtripplanner favored shorter charging stops with lower SoCs upon departure (blue line).  So long as the program’s initial estimation showed that there would be enough energy to reach the next planned charging station with a 20% reserve, the planned SoC for departure was deemed sufficient by evtripplanner.  We clearly favored longer stops to ensure that the SoC upon departure would get us to the next charging station with a comfortable reserve even if the efficiency fell well below that projected by evtripplanner (red line).  The higher SoC upon arrival offset some of the extra charging time resulting from higher SoCs upon departure.  By charging significantly more than was planned, we usually arrived at the next charging station with a higher SoC than evtripplanner projected.

Did the plan come reasonably close to guidance from the car navigation system during the trip?

Our experience was that the plan and the car navigation system agreed reasonably well.  That means that the planning tools can be used with a high degree of comfort, so long as one’s driving matches the information used in the tools.  Even so, deviations can arise, as with our higher than expected energy usage between Lander and Jackson.

How well did the car’s own guidance track actual results?

We used the Model 3’s navigation system all of the time.  There were two reasons for this.  The obvious one was to know where we were going.  The second, known to Tesla owners, is that when the car is asked to include Superchargers in the routing, the car will bring the battery to the ideal temperature for charging just prior to arrival at the next SC.  That reduces the amount of time needed to charge.  We found the navigation system’s projection of SoC in percent to be a more reliable reference than the battery icon SoC in miles.


It has become relatively easy to undertake major cross-country trips by EV given the number and location of charging options throughout the country.  Planning tools like, EV Trip Planner, and PlugShare are reliable and comprehensive.  Other planning tools like EVHotels are also gaining ground.

After we completed our trip, we revisited the question of which car to take on the trip.  As of June 30, 2019, Susan’s car had 18,842 miles on it.  It had been charged a total of 4,761 kWh, and efficiency was 253 Wh/mile (3.95 miles/kWh) for an estimated battery range of 316 miles.  Jack’s car had 13,805 miles.  The total charging was 3,813 kWh for an estimated efficiency of 276 Wh/mile (3.62 miles/kWh). That would give an estimated battery range of 290 miles.  So Susan’s single motor RWD car should go about 26 miles further on a full charge, or 21 miles further on an 80% charge.  Given the distances between chargers, we would have stopped just about the same number of times in the same places, but maybe for a few minutes less. When would the better range matter?  On the Lander to Jackson leg, given that we added 33 kWh at Lander, that would have gone about 10 miles further in the RWD car than in the AWD car.  We would still have had to manage our driving, but we would have arrived in Jackson with about 10% charge (30 miles) rather than 6% (19 miles).  That difference would have reduced our range anxiety recovery from two glasses of wine each to one.

Given the advantages in operating costs and low maintenance, EV travel is the best way to go.  Plus, they’re fun to drive!

Comparison to Tesla Vehicle Ratings per the EPA

Susan’s 2018 RWD Model 3

  • 130 MPGe (Miles Per Gallon Equivalent)
  • MPGe:  136 City  123 Highway  26 kWh/100 miles
  • Range:  310 miles per charge

Jack’s 2018 AWD Model 3

  • 116 MPGe
  • MPGe:  120 City  112 Highway  29 kWh/100 miles

In this blog, efficiency has been reported in Wh/mile or miles/kWh.  For the RWD Model 3, the EPA values are 260 Wh/mile (3.85 miles/kWh).  For the AWD Model 3, the EPA values are 290 Wh/mile (3.45 miles/kWh).  Over the course of the trip, the AWD car had an efficiency of 276 Wh/mile (3.62 miles/kWh), slightly better than the EPA estimates.

Some Numbers

  • Duration: 18 days (13 states, 4 National Parks, 2 National Monuments, 1 National Memorial, 1 State park, several roadside attractions)
  • Distance driven (per odometer): 5,277 miles
  • Distance driven (per charging notes): 5,245 miles
  • Energy use: 1,540 kWh
  • Average Wh/mi from car charging records: 294 Wh/mi (based on 5,245 miles)  3.4 mi/kWh
  • Average Wh/mi from Energy use and odometer: 288 Wh/mi (based on 5,277 miles)  3.5 mi/kWh
  • Estimated energy cost:  1,540 kWh – 33 kWh (Lander, WY, paid separately) = 1,507 kWh @ 12 cents per kWh = $180.84
  • Out of pocket energy cost:  $5.00
  • Total estimated energy cost:  $185.84
  • Average price of regular gasoline near charging stations:  $2.75
  • Estimated energy cost for an ICE vehicle getting 30 mpg (odometer mileage):  $483.72
  • Energy savings over ICE vehicle:  $297.88
  • Estimated maintenance cost not needed following trip (oil change, minor tune up, etc.):  $40 – $100 
Charge, the end of the trip
Finally.  © 2019, Susan and Jack Goodwin 


Tesla Referrals:

  • If you’re thinking of buying a Tesla, you may find an advantage like some amount of free supercharging if you use someone’s referral number.  Just enter the referral into your web browser when you go to the Tesla website to place your order. 
  • Susan’s Tesla Referral Number:

Energy Use, Charging, and Routing:

  • A Better Route Planner []
  • EV Trip Planner []
  • PlugShare []
  • Tesla Go Anywhere []


  • Atlas Obscura []
  • Badlands National Park []
  • Chico Hot Spring and Resort []
  • Corn Palace []
  • Crazy Horse Memorial []
  • Custer State Park []
  • Devils Tower National Monument []
  • Elk Refuge Inn []
  • Garden of the Gods []
  • Grand Teton National Park (GTNP) []
  • Linger [[]]
  • Little Bighorn National Battlefield Monument []
  • Mt. Rushmore National Memorial []
  • National Elk Refuge []
  • Porter Sculpture Park []
  • Rocky Mountain National Park []
  • Wall Drug []
  • Yellowstone National Park (YNP) []
  • YNP App [],


  • EVHotels []
  • []
  • Trip Advisor []


  • Jack and Susan’s Photography website []

Tesla Forum:

  • Tesla Forums []




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