Supercharger Station Hopping Across Virginia in My Tesla
I’ve been a Tesla owner for a year, gradually adjusting to driving an all electric car. Making this change requires understanding when and where to refuel. The supercharging stations are a huge benefit given how quickly they can refuel your car. My normal out-of-town travel has been up and down the densely populated I-95 corridor covering the DMV (Delaware-Maryland-Virginia) area.
This past weekend I ventured away from I-95, and headed out to the Blue Ridge mountains along the western part of the state. Here is a journal of my all electric experience with actual data around how well my car’s battery performed, as well as the charging stations along the way.
Road Trip to Southwestern Virginia
First came planning out the trip. I was up in the DC area for work, so would be traveling almost the length of the state. Before getting on the road, I plotted my options to get from McLean to Christiansburg.
The model of Tesla I drive is a S75, with a maximum battery range of 249 miles. Given that the trip was 258 miles, this trip would test my charging skills along the way.
Researching the Tesla website highlighted options on all the major highways. Interstate 81 is the main path along the Blue Ridge Mountains, and has three Supercharger stations. Interstate 64 connects to it in the mountains, and allows for travel East to Richmond and the Virginia Beach area on the Atlantic. A Supercharging station is available on it in Charlottesville, as well as in my hometown of Richmond.
Let’s get this trip started!
I left the office in McLean at 2:15PM on Friday, and had fully charged my vehicle in the office garage. The energy gauge indicated 243 miles range in the battery — 98% of it’s maximum capacity. Traffic getting out of the Northern Virginia suburbs was busy, but after 25 miles it opened up. The speed limit for Interstates in the rural areas is 70 MPH, and these roads are filled with truckers that enforce going fast. The weather was a cool March day in the lower 40’s. This influences the efficiency of the battery on the trip.
After driving for 90 minutes, it was time for my first charge in Mount Jackson. As of 3:44PM, the energy gauge had dropped to 118 miles, but I had only travelled about 100 miles. Traffic, weather, and speed added 20% resistance from perfect conditions which is what the onscreen gauge calculates.
The charging station was just two-tenths of a mile off the highway in a Sheetz parking lot. Given that I was the only one using it, the energy transfer rate was very good. With the battery around 50%, the charge started at 89 kW. I stretched my legs, did a bio break, and got something to drink. After 19 minutes the station added 70 miles to the battery and was ready to go.
Planning my Arrival
At 4:03PM, I continued my trip, and monitored the battery consumption with the onboard navigation. It constantly forecasts the energy utilization, and after settling in set my expectations that I would be cutting it close without another charge. An additional point to consider is incidental travel once you reach your location. I was going to attend my daughter’s swim meet, so arriving on empty wouldn’t be a good plan.
I added another charging stop, and the onboard navigation gave me the directions. At 5:23PM I arrived at the supercharger station in Lexington, and was down to 95 miles of energy. The battery usage efficiency was similar, with a 20% reduction due to vehicle speed and colder temperatures.
Once again I was the only car charging, although I didn’t get a great energy transfer rate (75kW) given the battery was relatively (60%) full. When planning stops, that’s a consideration given that the lower your battery level, the faster the charger can refuel. A Supercharger station is rated up to 120kW, but to achieve that level requires a nearly exhausted battery.
At 5:41PM I pulled out of the stall, adding 59 miles of energy in 18 minutes. This gave me plenty of energy to finish the trip. I arrived in Christiansburg at 6:55PM, and still had 54 miles of energy in the battery.
The hotel that we stayed at in Blacksburg had a free charger station in the parking lot. It even had a Tesla cable, so I could plug right in. Charging speed was 10kW, much slower than at the Supercharging stations, but given I had all night, was not an issue. The seven hour charge got me from 46 miles back to full at 243 miles.
After a fun weekend, we headed back on Sunday afternoon. I live in Richmond which is a 200 mile trip. The energy gauge registered 232 miles at the start, and the temperature was up around 50 degrees. This was slightly better than on Friday, although vehicle speed would be similar given the highways involved.
I got on the road at 1:40PM. After entering directions, the car warned me that although I may have enough to get back to my house, the battery would be very low. The map highlighted two Superchargers on my trip, and gave advice to stay below 65 MPH to maximize the efficiency of the battery.
I drove for more than an hour, and at 2:55PM stopped into the Lexington Supercharger station for a bio break and to grab a snack. The energy gauge was down to 143 miles, and charging started at 70kW.
After a 15 minute break, it added 46 miles of charge. The onboard computer stopped giving a warning signal about the range to destination, and arrived home right at 5:00PM. The total trip was just over 200 miles, with only 43 miles left in the battery. Calculating that versus the forecast in the trip computer indicates a 15% efficiency loss due to vehicle speed and temperature.
The trip was a success, and improved my confidence in going into more desolate places. Here is a summary:
- Fast highway speed and cold outside temperatures can reduce battery efficiency by up to 20%.
- 15–20 minute charges are painless, and provide an opportunity to grab a beverage or snack and a bio break.
- How full the battery is influences the charging rate at a Supercharger. When 50–60% full, expect around 75–80kW, or around 3-4 miles/minute. If the battery is further drained, it will initially charge faster.
- In Virginia, the Supercharging stations are not too far away from the major highways. This minimizes the inconvenience of frequent charges.
- Hotels with charging stations are AWESOME, and allow for restarting the next day on a full tank despite slower charging speeds. These are slower — a 10kW charger transfers 30 miles/hour.
- The onboard energy forecasting on the 17" display is very helpful, although calculations are based on ideal conditions.