I finally took my first Tesla Model 3 road trip, driving 625 miles from Marietta, GA to Lake Worth, FL. I'd read a ton of posts beforehand for road trip tips & tricks, so thought I'd share my newbie impressions, including a few things I personally hadn't read or known before my trip.
- Supercharger stalls aren't always in sequential order! - I knew to avoid sharing a Supercharger numbered stall, in order to avoid sharing power with another user (say, avoid stall 1B if another car is already in 1A). I was surprised to realize at my first stop, in Tifton, GA, that the stalls are laid non-consecutively! This actually came into play at my second stop, in Lake City, FL. I arrived to find all six stalls empty, but soon another Tesla owner showed up to charge. They parked 3 stalls down from me... and sure enough, they'd managed to pick the stall that shared my power! My charging rate immediately dropped from around 570 miles/hour to around 280 miles/hour. I unplugged, moved my car one space over, and resumed charging at the higher rate.
- Supercharger stalls aren't all created equal! - upon arrival at the Turkey Lake, FL Supercharger station, I was the only car there, and parked at the first stall. I was surprised to see a charging rate of only around 280 miles per hour after a few minutes. I disconnected and moved one space over, and immediately saw nearly 600 miles per hour. It's as if that first station "thought" I was sharing power with another car. Lesson learned - keep an eye on the charging, especially for the first few minutes.
- Mental math - while Supercharging, the display shows your connection's wattage (say, 146 kW), along with your charging rate in miles per hour (say, 600 miles per hour). Each charging session started pretty close to the 150 kW maximum capacity of the Supercharger. The wattage steadily drops as your battery fills up, but I found the ratio of kW to mph stayed fairly constant, at around 4.1 mph per kW. (For example, towards the end of a charging session, I'd dropped to 35 kW, which also displayed as 144 mph.) Upon reflection, this makes perfect sense - the mph is just an estimate, similar to the "miles remaining" the car shows on its main display, which typically overstates actual miles remaining by about 20%. To break down the math a bit more - my Model 3 Long Range battery's capacity is 75 kWh, and the advertised (optimistic!) range is 310 miles, so in theory the car can drive 4.1 miles on a kWh of energy. This is the same 4.1 ratio used in the display of charging mph based on kW.
- How much charge to arrive with? - I never quite figured out the lowest charge the Trip Planner thinks you need to have when you arrive at your next Supercharger, but I think it's around 8-10% (or about 20-25 miles). When you start charging, the Trip Planner shows how much battery charge you'll have left if you departed right now. This figure starts at some dramatically low figure (say, -15%) and you can watch it gradually rise. At the same time, the car (and the Tesla mobile app) are telling you how much time you have left to charge. This time seems based on some combination of the minimum amount of additional charging time you'll need to arrive with at least 8-10%, while also factoring in the benefit of staying at a charging station for awhile longer if you're still getting a reasonably fast charging rate. I say the latter part because sometimes the recommended charging time left me with closer to 20% charge remaining at the next stop. I'd love to find some comprehensive explanation of the algorithms used by the Trip Planner. In any case, I learned to trust the Trip Planner, and it never led me astray, although I got nervous on the very last leg home. The final charge back north, in Tifton, GA, projected to get me home with 8% charge. Once underway, this estimate varied between 6-11%. I ended up home with 7% charge - no sweat, I guess, but I never hit any serious traffic, didn't need to stop for a bathroom break, etc. and I wonder how quickly that 7% could have bled away if things hadn't gone as expected. On the other hand, once your battery is already at, say, 95% charge, those last few % of charging take forever, so it's very tempting to leave when the car is saying it's okay to leave. In the end, my takeaway really is - trust the Trip Planner.
- The online Tesla trip planner doesn't match what the car tells you - not even close. I'd pre-planned my trip at Go Anywhere | Tesla, but found the car itself came up with a very different plan when it was time to depart - different times spent at each charger, fewer charging stops, shorter overall trip duration. The in-car Trip Planner proved to be extremely accurate. The web page is still good for a general overview of where the Superchargers are, but I wouldn't count on executing the trip according to the strategy it lays out for you. I'm aware there are 3rd party websites that also do EV trip planning, and I plan to try a few more of them before future road trips.
- Supercharger stations can be... barren - I ended up stopping at three Superchargers at Florida Turnpike service areas, and two regular Superchargers (Tifton, GA and Lake City, FL). Having Superchargers at the turnpike service areas is fantastic, but my overall wish list for all the stations would include -
- A few benches, to sit and get some fresh air. This would be a quick, cheap fix that would greatly enhance all the stations I visited.
- A nearby trash can.
- A tire air dispenser (I used the one at the Shell station at one of the turnpike stops - that was convenient).
- Obviously, restrooms. (Turnpike stops - already got 'em. Otherwise - I visited a Firehouse Subs, and a nearby gas station).
