2013 Tesla Model S: Road Trip Recharging Strategy
January 10, 2014
A few commenters were critical of the recharging strategy I employed during my 2,000-mile road trip in our long-term 2013 Tesla Model S. Namely, I'd fill only partway, putting in enough miles to reach the next Supercharger, plus an extra buffer. For this I was chastised as an EV newbie and tut-tutted for not doing complete charges.
The irony here is that those doing complete charges at each Supercharger are revealing themselves as EV newbies. The reason is time. Filling the last 20% doubles the amount of time you're sitting at the Supercharger compared to filling to 80% from empty. Science!
Since my route required recharging at every Supercharger along the way, the most time-efficient strategy is to roll into each Supercharger with a nearly-empty battery, put in enough miles to reach the next one (plus a bit more, just in case), then hit the road. Doing a complete charge at every Supercharger would have been a colossal waste of time, adding hours, not minutes, to an already long trip.
In fact, partial fills in this manner are recommended on Tesla's website:
The fastest way to replenish your Model S is to charge to 80% state of charge, which is more than enough for travel between Supercharger stations. Charging the final 20% takes approximately the same amount of time as the first 80% due to a necessary decrease in charging current to help top-off cells. It's somewhat like turning down a faucet in order to fill a glass of water to the top without spilling."
What's needed is route topography to be taken into account in the Tesla's navigation system. You'd program your route and the system would make a rough estimate of how much additional range will be sucked out by hills along this route. Easy for me to say...
Incidentally, when you're on the fourth recharge of the day and you've eaten all the crummy fast food you can stomach, done plenty of aimless walking around, caught up on emails, your bladder's empty and you're parked in the back of a restaurant parking lot in Grant's Pass (colloquially referred to as "Grant's Ass") in winter, getting back on the road and making some kind of progress toward your destination becomes your mission in life. Stopping every 150 to 200 miles does lose its novelty in a hurry during a trip like this.
Jason Kavanagh, Engineering Editor