I was going to spend a portion of my summer in California and I was debating whether to drive cross-country or have a rental for my summer stay. Cross-country trips are challenging enough but in this case, it turns out to be even more interesting since I drive a Tesla Model S with a 60 kWhr battery pack (rated range is close to the newly announced Tesla Model 3). I have owned it for about 2 and half years and have done several drives to Washington DC and back. It has largely been seamless and very comfortable especially given the autopilot functionality. Finally, after much deliberation, my wife, Ramya and I decided to do the cross-country trip.
“Well, Venkat really talked me into it with being both a quintessential summer road trip and a futuristic ride. Mostly, I thought it would be better to be part of the adventure than fielding calls about logistics all day and wondering if Venkat had made it to the next stop.”
The timing of the cross-country road trip could not be more appropriate. The trip started a day after the DoE Annual Merit Review (AMR) meeting for the Vehicle Technologies Office (VTO). This meeting brings together the leading battery researchers who present their work and prove the merit of their work to a team of reviewers. This year, I was attending to present on our joint project with Yet-Ming Chiang (MIT) on self-forming films that could enable lithium metal anodes for next-generation batteries.
At the meeting, David Howell, Deputy Director of VTO, announced the next big goal for electric vehicle batteries: cost less than $100/kWh (useable), increase range to 300 miles and decrease charge time to 15 minutes or less. The ultimate cost target would be $80/kWh. Howell further remarked that the research work supported by DOE has led to significant battery cost reductions, around 3x reduction since 2008. Current estimates are that LG Chem cells to GM cost~$170/kWh (useable) and an estimate of around ~$223/kWh (useable) for the Tesla batteries.
In 2008, when I had started my graduate studies and began researching Li-ion batteries, such numbers would be completely unthinkable and the previous DOE target was similarly thought to be very difficult to attain. We have come an incredibly long way and probably the best account of this electric car revolution is the book, “The Powerhouse”, a book written by a good friend, Steve LeVine. The AMR meeting gives me a chance to sit down with Steve and talk; most of this time is spent discussing trends at the intersection of autonomy and electric. On this occasion, we discussed my upcoming cross-country road trip from Pittsburgh to California.
Planning: I landed back in Pittsburgh following the AMR meeting and started planning for the trip. This involved mapping out the route and given time constraints due to prior commitments, we had about 4 days to complete the road trip from Pittsburgh, PA to Palo Alto, CA. We used the excellent tool built by 19 year-old Ben Hannel, EVtripplanner.com for mapping out the trip. We spent one evening booking accommodation at places where we could charge overnight using Tesla’s destination charger list. In all, it took us about 2–3 hours for the planning the trip.
“While EVtripplanner has a default buffer charge of 15%, we brought it down to 5%. Unbeknownst to me, Venkat decided to skip some of the stops it suggested. This made our second day really long. In hind sight, I would definitely recommend an additional day.”
Day 0: This involved a trip to AAA to get EZPass to manage all the tolls and paper maps to ensure we would not get lost should we lose network reception. Ramya had downloaded Steve LeVine’s “The Powerhouse” audiobook for the drive, very apt!
Day 1: I started the day around 8 AM from Squirrel Hill in Pittsburgh, loaded up the car, both in the trunk and the frunk (front trunk). I was going to pick up Ramya from the Chicago airport around 8 PM and we were going to reach the border of Illinois/Iowa and stay at Davenport in the Beiderbecke Inn. The first stop was going to be in Macedonia, OH, about 120 miles away. I got on to 376 freeway and turned on autopilot. After a few minor human interventions during the freeway transitions, I reached Macedonia supercharger. After a quick stop of about 20 mins, I was on the road again with autopilot driving me to Maumee supercharger. Maumee supercharger is located in the parking lot of Meijer. Meijer pays for the electricity and it is wonderful to see Meijer’s progressive initiative. I briefly chatted with many other Tesla owners charging at Maumee. After a nearly fully charged pack, I hit the road again towards Indiana with the next stop being Mishiwaka. Mishiwaka supercharger is very well located in a large shopping mall close to University of Notre Dame and I stopped briefly at the Barnes & Noble. I hit the road again with the next stop being Bolingbrook, IL. This is about 25 miles from the O’Hare airport and this would give me time to leave according to the arrival time of Ramya’s flight. I drove through part of the Chicago traffic and autopilot handled it very well. I was just about to reach the Bolingbrook supercharger when suddenly autopilot became unavailable and there was a sudden downpour. At the Bolingbrook supercharger, I called Tesla Roadside Assistance to ask about why the autopilot suddenly became unavailable. I had driven about 20 miles during the day and the rest was on autopilot. Suddenly, I felt crippled should the autopilot not work for the rest of the trip. The Tesla Roadside specialist suggested that I clear the dirt around the radars, 6 in front and 6 in the back and cameras. I did that and then voila, autopilot was back! This became a ritual at every single subsequent pitstop — plug the supercharger cable, clear the radars in the front and back, clear the area around the cameras and place the sunshade, in that order. Around 8 PM, I set out to pick up Ramya from the O’Hare airport (luckily, no flight delays!) and we set out towards Beiderbecke Inn.
“Most of Friday morning, I was at work but received regular updates from Venkat on his location — it seemed liked he was making good progress and I was rather surprised that the mileage and timing were all according to plan. When I landed in Chicago, Venkat was making his way down to Chicago from Bolingbrook, this gave me enough time to pack some food from the awesome Tortas Fronteras.”
“It was a rather annoyed Venkat that picked me up at the airport, thanks to the Illinois toll system. If you are new to the E-ZPass system, I would highly recommend buying it ahead of time, installing and making sure it is registered and can be read at the tolling stations. What seems like a simple thing can add unnecessary delays and stress. If it does not work, it is best to drive through and pay online later rather than deal with the coin catchers which clearly do not differentiate quarters and dollars. We learnt this the hard way after multiple attempts with these coin catchers. To get out of Chicago area we decided to take a toll free state route which also avoided the majority of the traffic and joined the freeway back near Naperville. We ate our tortas on route thanks to autopilot. Although I had seen autopilot in action earlier on shorter drives, I did not realize what it meant on a long-distance ride . It is definitely much less taxing even though you are still paying attention.”
We stopped very briefly at North Aurora supercharger to add just a few more miles so that we could reach Davenport, IA.
“At North Aurora, I called Pam at Beiderbecke to let her know we were running late and they were kind enough to accommodate a 12:30 AM arrival. Dennis was waiting for us out on the porch as we pulled in. We made it with 9 miles remaining. After exchanging quick notes on the Tesla’s and thanking him for waiting up, we were shown to the Bix room. Walking into Beiderbecke felt like walking into any erstwhile era, complete with tiny lights standing in for candles at each window. We had found the place on Tesla’s destination charger map and were just looking for a quick overnight. The room was spacious, beautifully decorated and comfortable, unlike other Victorian inns that can be stuffy.”
Day 2: We had breakfast in the morning and chatted at length with Pam and Dennis, who shared stories of their own road trip with their Tesla. With a fully charged battery pack, we were on our way with the first stop being West Des Moines. The rated range as we rode away from Beiderbecke Inn was 212 miles. The distance to the supercharger at West Des Moines was 180 miles. The speed limit in the rural parts was about 70 mph and this immediately lead to a drastic rise in the energy consumption. I figured that the 30 mile buffer was sufficient to overcome the additional aerodynamic drag.
“It was the confidence that comes up with the smooth day one of a cross-country road trip that led us to make these allowances and throw caution to the wind.”
This day showed why Nebraska and Iowa feature as the windiest states in the United States. We had to slow down and go below speed limit to lower the aerodynamic drag and still reached West Des Moines with about 9 miles left. One thing all our research on EV range ignores is wind speed as a variable to describe the vehicle dynamics. Immediately, I dropped a note on our research group Slack channel to incorporate this.
“The supercharger at West Des Moines was in a scenic location in the Hy-vee parking lot, with rolling hills and a small creek running nearby. We had lunch at Zuzap which was a bit of walk in the sun but worth it. The food was spicy and tasty! Following this, we started monitoring wind speed and direction. Most of Iowa and Nebraska had cross-winds on the I-80W. We stuck to driving about 5 mph below the speed limit to maximize range and lower the aerodynamic drag.”
We were conservative for the rest of our drive on Day 2 and stopped briefly at Council Bluffs. This supercharger is well-located with a Charming Charlie and other stores nearby. Next stop was Lincoln, Nebraska where the supercharger is located in the Hy-vee supermarket parking lot. Like Meijer, Hy-vee supermarkets support the Tesla supercharger network. Following this, we made it to Grand Island where the supercharger is located in the Bosselman Travel Center, a popular stop for semi-trucks and there were over 50 of them. It was a stark contrast to see the supercharging station and all the diesel semi-trucks that were parked behind it. Earlier in June, our research group had published a paper on the potential for electrifying semi-trucks and the challenges that lie ahead, and covered in a Wired article. A reminder that we have miles to go before fully electrifying transportation. On a side note, it was already around 7:30 PM and we had over 400 miles to go before we could sleep that night at the Denver Hampton.
At the Gothenburg supercharger, we saw the first Tesla for the whole drive through Iowa and Nebraska.
“It was already past 9 PM and this was when I began wondering if it would be wise to stop earlier and drive to Denver the next day. The supercharger was in the Comfort Suites parking lot and we went in. The decision was made for us when we walked in and overheard an argument on overbooking of rooms. Apparently, there was an RV conference in the area and all the rooms were booked out.”
We went on to Ogalalla, where the supercharger is located in the parking lot of Holiday Inn Express. This was the first time we saw non-EVs taking up the Tesla spots due to the same RV conference. Luckily, we found a charging spot and went inside the Holiday Inn Express and heated up the dinner we got at the Hy-vee in Lincoln.
“I knew the next two legs involved a steep elevation gain and we were driving at night, so we definitely needed more buffer charge. On the other hand, Venkat was itching to leave sooner. I had to find ways to delay by occupying him with tasks that were not critical while the battery was getting more juice.”
The next stop was Brush in Colorado and the first deviation from I-80 for the day. We were the lonesome car on the I-76 for a large part of the way and certainly, the lone car at the Brush supercharger. We caught a beautiful glimpse of a nearly full moon night and after a brief stop at Brush, we marched onwards to the Hampton at Denver airport. In all, we drove about 845 miles (rather Auto-pilot drove 830 miles and I drove about 15 miles) and by far, the most tiring day of the road-trip.
Day 3: After a good night’s rest, I turned the TV on in the morning to try to watch at least a part of the French Open finals between Nadal and Wawrinka. I expected a marathon match but Nadal breezed through. After a nourishing breakfast, we set off for the day and arguably one of the most scenic drives on the I-70. The first stop was Silverthorne where the Supercharger is behind a beautiful backdrop of the Rockies.
“The ride up to Silverthorne had a steep elevation gain of over 3000 ft. After the Iowa winds the previous day, the challenge for day three would be the Rocky mountains! We met another Tesla owner who had never used autopilot before. Venkat showed her how to use it and she was very surprised to learn that we had used it so extensively.”
Next stop was at Glenwood Springs, which had an elevation drop of about 3000 ft from Silverthorne. We saw the battery pack storing energy on the downhill and I rationalized why the energy stored going downhill for the most part does not depend on the speed. With a fully charged pack, we set out for Grand Junction.
“It was great to see the battery indicator go down into the green — it made the downhill drives all the more enjoyable! I knew about regenerative braking but definitely did not realize the scale of energy storage from just going downhill. The Grand Junction supercharger is a bit away from the lively downtown. However, there is a small mall near the supercharger, we ate at Zheng Asian Bistro- another good find.”
A quick pitstop (20 min ) later, we set out for Utah, still continuing on I-70. The first stop in Utah was at Green River supercharger which is located at the River History Museum. After a brief debate about whether to stop for dinner, we decided to continue onwards to Price, as we moved away from I70 and onto 6N.
“Not to be outdone by Colorado, Utah provided some spectacular scenery as we drove up along 6N. This was a single lane road and autopilot had some difficulty finding the outer lane marker- this meant it was sometimes a little too close to the center line for my comfort. Venkat had to take over when there were big-rig trucks passing by so we could stay a little further to the right.”
Price supercharger was in the parking lot of a new Holiday Inn express. Another short stop and we set off for Salt Lake City. The entry towards Salt Lake City was the first stretch where we encountered traffic all day. The autopilot handled the stretch extremely well. The Salt Lake City supercharger is located at the Tesla store and we briefly chatted with the other Tesla owners charging there.
“The rest of the drive before connecting to I-15N also provided beautiful sunset panoramas. Once we joined I-15N , this was the first time we saw real traffic and I was a little nervous initially if the autopilot could manage the unruly drivers on the road. After a while I relaxed as I saw it maintained good distance and slowed down in time.”
Our rest stop for the night was at Peppermill Inn in West Wendover, NV, which is a tiny town that has the Mountain Time Zone.
“The drive to West Wendover was the last stretch and had a positive elevation gain. We faced crosswinds and we were doing this drive starting around 9:30. Typically, we dealt with high winds by slowing down temporarily but the speed limit here was higher and it was not safe to slow down too much while sharing the road with other 18-wheelers. The winds were particularly gusty near the salt flats where even the road signs were blowing over. After what seemed like an eternity, the bright lights of West Wendover showed up on the horizon.”
Day 4: Given the supercharger was located across the street from Peppermill Inn, I drove the car to the supercharging station at West Wendover, located next to the Chevron gas station, a beautiful contrast and a picturesque David vs Goliath. We set off for the last day with great excitement and the first stop was Elko where we had breakfast at Denny’s. The temperatures were low (~5–10⁰C) and add to this there was pouring rain. Just when we thought we had seen all the hurdles, we were now about to face the dreaded range reduction in cold weather.
“We decided to get an early start and get breakfast at the first stop -this was a smart decision and probably something we could have done on the other days as well. But just a few miles into the drive, temperatures started plummeting. I had seen this earlier — how the range dropped and how charging took a longer time at lower temperatures. But the mileage between the first few stops was not too high, so it didn’t add too much to our charging time.”
There was a snow warning for a part of the stretch on the drive from Elko to Winnemucca. The autopilot handled this part extremely well, very likely better than a human driver. After a brief stop at Lovelock, where Ramya refused to step outside the car, we set off for Reno. The Reno supercharger is located in the Atlantis and we played a couple of rounds of Blackjacks.
“The car handled surprisingly well on the small stretch of road with fresh uncleared snow. Reno was a nice break from the typical supercharger routine that we had gotten into.”
With an almost fully charged car, we set off for the Golden State. Seeing the “Welcome to California” sign brought a sense of familiarity, a homely feeling, for both of us. Ramya did her graduate studies at University of California, Santa Barbara while I did mine at Stanford.
“As we headed towards California, we caught a glimpse of the Gigafactory, tucked among the hills in Sparks. The temperatures plummeted again as we crossed the Sierras and there was more fresh snow, but we were less worried now after dealing with it earlier in the day and we were also back in Cali.”
We reached the Roseville supercharger and it was undoubtedly clear, we had reached the EV state; 5 out of the 7 supercharging spots were taken (the most use we had seen throughout the entire trip). After taking an overjoyed selfie, we set off for Palo Alto.
“Roseville charger is also in the familiar Westfield Galleria mall, we picked up quick dinner from Pluto’s; but could have easily spent more time here.”
We reached around 10 PM to our friends, Bonnie and Alan’s house. I plugged the car into an 110V outlet and left the car to charge overnight.
The trip was truly futuristic in many ways:
- Autopilot drove over 90% of the trip.
“Autopilot totally surpassed my expectations and I am looking forward to using it in my Model 3.”
- Supercharging network is vast and adequate even with a 60 kWhr pack for cross-country road trips. This adds even more belief that even the normal range Model 3 with 220 miles is sufficient for most people.
“I would say these are adequate as long as the superchargers are not full . Even if we had to wait at any one of them, it could add 30-45 min that we didn’t account for and would throw us off our itinerary.”
- “Range anxiety” is something that could be managed, even if not completely overcome.
“Although there are tools out there to predict range and I am sure they will get better with time, none of these right now dynamically take into account local weather patterns or windspeed in the direction of travel. We constantly adjusted the estimates and driving speed based on these factors and back-of-the-envelope estimates that Venkat made. Our car did not have the Tesla navigation system so we cannot comment on its functionality. For the average driver, there is not enough information to just get in the car and drive across the country. We would need a lot more information or range estimates that are dynamically updated. In lieu of this, a wider supercharger network would also help so one could add an additional stop on an especially cold or windy day.”
- On a professional note, the energy density (and specific energy) of current Li-ion batteries are probably good enough for the passenger sedan market.
With a growing realization that mass-electrification of the passenger sedan market is imminent, the next day, I set off for a mid-year review meeting for a project supported by NASA on electrifying flights. The project aims to use lithium-air batteries to power electric flights and Steve LeVine wrote a great piece covering this project. With electrification of trains and automobiles taken care of, planes represents the final frontier!