December 29, 2013
World Record Father-Son Drive
David and Adam Metcalf
December 13, 2012
In May 2012, ahead of the first deliveries of Model S, Elon wrote about the unmatched efficiency and range of Model S and announced that the team at Tesla had exceeded the goal of delivering a range greater than 300 miles with the 85 kWh battery. In that blog, he also issued a challenge: a prize to the first customer able to drive over 400 miles in a Model S on a single charge. Six months later, Model S owner David Metcalf and his son Adam took up that challenge. After almost 17 hours and 423.5 miles, David and Adam had shown it could be done.
Here’s their story:
In the wee hours of a November Saturday morning my son Adam and I took off in our Tesla Model S on a father-son journey to attempt to break the world record for furthest distance traveled on one charge in a production electric car and to be the first team to meet Elon Musk’s grand challenge to go 400 miles on a single charge. We’re happy to report that we managed 423.5 mi/681.6 km and broke Tesla’s record as the first to drive more than 400 miles!Route
Route planning was essential. Our journey took us to very flat, rural parts of Central and South Florida, driving around Lake Okeechobee, through the Florida Panther Preserve, across Alligator Alley, through Ochopee and Miccosukee tribal villages, around Big Cypress and Shark Valley and back up to the Northern side of Lake Okeechobee, ending up at the intersection of Martin Hwy and I-95. The slow and steady pace (~25 mph) allowed us to drive very efficiently while enjoying beautiful Florida wildlife and scenery. It was nice father and son bonding time during the almost 17-hour trip. “It was pretty cool; I had a fun time with my dad,” said Adam.
Adam copiloted, took pictures, tracked mileage, energy use and calculated our progress toward the 400-mile goal. With two people in the car versus the recommended solo driver, we decided to drive a little slower and bank some energy in case we ran into stops, traffic, rain, hills, rough roads, etc. We did hit heavy fog and construction traffic along Alligator Alley, had about four and a half hours of rain, crossed causeway and lagoon bridges, and traveled along many sections of roughly graded road that greatly reduced our efficiency. We had some good luck as well—we only had to stop at seven of the 15 to 20 stop lights along the route using coasting techniques. We only made two stops for a total of 17 minutes and a photo/confirmation stop at 405 miles. Steady, precise driving paid off with an average energy use of 190 Wh/mi in spite of the challenges.Preparation And Driving Techniques
Some planning and review of prior attempts discussed on Tesla Motors Club, Tesla’s chief technology officer, JB Straubel’s recommendations, techniques from research teams in Japan and Germany, and recommendations from my NASA Engineer neighbors helped identify many ways to drive as efficiently as possible. The Model S was a standard configuration with the large 21” wheels. We compensated for greater rolling resistance by overinflating the tires. With temperatures ranging from 64 to 80F, we were able to forego A/C and only use the vent and lower the windows three inches later in the day with no perceived decrease in range. We also had handheld and solar fans in case the heat of the day became too much. Using cruise control was also essential, but we only engaged it once at the desired speed which allowed for increased efficiency through slower manual acceleration. The most significant, unexpected range killer were roads with a slightly rougher grade than a highway or interstate and caused range to decrease by 8 to 15 percent. I tried to drive slightly off center of the grooves when there was no traffic and this helped a bit.
Beyond readying the car, preparation for the endurance drive required provisioning of food and water (we only saw eight restaurants and seven gas stations open once we left our populated home area) and infrequent stops helped with range. The drive could have been grueling with just one driver if it weren’t for training for other hobbies like surfing and running ultramarathons, which consists of running continuous distances between 50 kilometers and 100 miles. The ability to stay awake and alert through the monotony of low speed driving, especially at night when the beautiful scenery was hidden, should not be underestimated for your own safety and others on the road. While I did not find it easy, my training for long duration activities was useful. It was also helpful that Adam was old enough to not ask “are we there yet?” even once during the whole trip.
While I do think drafting and downhill coasting are potential range enhancers, close driving and winding roads, where resistance on the tires is heavy, can be dangerous and may not outweigh the risks. Driving 450 miles is definitely achievable in my view and I wonder if 500 miles could be met under perfect or more modified conditions.
Many have asked what the prize for being the first to drive more than 400 miles was. I received a High Power Wall Connector plus installation that I have donated to the university where I teach, University of Central Florida. We plan to install it in a public location so that it can be used by other Tesla owners who come through Orlando. We will most likely have a scheduling app in case it becomes a popular stop for free power. Feel free to take advantage of it once you have your Model S!
Photography by Jeanee James Photography
Read about Elon's Range Challenge