2013 Tesla Model S: Road Trip Range Anxiety
December 20, 2013
Admission: I sort of cringe at the expression "range anxiety." It's a trite, too-easy sound bite in any discussion of EVs. But in this case, it's apt.
It happened during the 139-mile stretch between the Superchargers at Grant's Pass, OR, and Eugene, OR during my recent road trip in our long-term 2013 Tesla Model S.
I'd left the Grant's Pass Supercharger with an ample cushion of miles in the car's battery. See, up to this point in my trip I'd observed that the "rated range" display in the Tesla's instrument cluster had been optimistic by 15-20% compared to actual driving conditions. To compensate for this reality, I'd been charging with a commensurate buffer of miles in addition to that necessary to reach the next Supercharger. No problem. In fact, at Grant's Pass I'd even thrown in extra miles on top of the buffer. Good thing.
While on the road I periodically compared the rated range to the miles remaining to my destination (as shown by the nav). It's something you find yourself doing out of habit in this car. And at one point after leaving Grant's Pass I saw that my buffer of extra electrons was being consumed at an alarming rate.
I'd been driving conscientiously, not running A/C at all on this trip, no heated seats, and just keeping the temp at a reasonable delta over ambient so as not run the heater too hard. Cruising speed was between 70 and 74 mph. No unduly abrupt or large throttle inputs. So far, it was an approach that was working well. But the terrain on this stretch, it turns out, was much hillier than previous legs, and it was quickly gobbling up range.
Once it became apparent that the rate at which the rated range and the digits on the nav display were attempting to converge could conceivably result in a bad day, I turned it down to 65 on uphill sections. Very shortly afterwards, I locked it at 65 at all times. Then 60. Then 55. We were crawling. I turned off all unnecessary current draws. The instrument panel was dimmed to its lowest setting. No radio. No iPods. Just trundling along the near-empty freeway at night in a $94,000, 461-hp car like a Prius driver. At least I wasn't camping in the left lane.
I rolled into the Eugene Supercharger station with 8 miles left in the tank. In retrospect this sure sounds like ample extra range so what's the big deal, but I have to admit that I was watching those digits like a hawk for most of the leg. And I was counting on no curveballs being thrown at me along the way. Had there been an unexpected freeway detour or an exit closure, I might have been calling a flatbed.
Instead I plugged the Tesla in at the Supercharger located behind the Holiday Inn in Eugene, OR, and walked away. It was in the low 30s outside. I found the nearest restaurant and had dinner.
Jason Kavanagh, Engineering Editor