With more than 2 years and over 60,000 miles of Tesla ownership under my belt and my first road trip and hard lessons long ago I figured a trip from the Boston area to the Tampa Bay area in my Model S would be pretty uneventful, but I found out that I still had lessons to learn.

Update/Note: I realized after I saw a number of comments on this post that I neglected to mention that I didn’t use Autopilot for any of this trip. My Model S, an April 2014 build, sadly doesn’t have the hardware or capability. The trip would have taken the same time with Autopilot but would likely have had some other kinds of experiences to share (good and bad i’m sure).

Routing

A quick trip to Google directions tells you it takes about 21 hours to drive from Boston, MA to Tampa, FL. Google factors in traffic patterns and speeds but doesn’t add any time to refuel, eat, etc. If you’re adventurous, you can simply hop in your Tesla and plug in the destination address and start driving. The Tesla navigation system will take you to your destination by way of any needed chargers along the way. If you get tired or it gets late you can find a hotel, take a stop and then carry on the next day.

For many of us, this casual approach to a lengthy trip isn’t palatable. We want to know where we’ll be staying the night, want to have reservations so we know we’ll have a good bed in a nice hotel, what places we’ll be at around meal times, and when we’ll arrive at our destination. Doing all that thinking and math while sitting in front of your Tesla navigation screen is frustrating. And if you want to add a stop somewhere along the way forget it, Tesla doesn’t support that.

Fortunately there’s a site that helps with some of the planning called EVTripPlanner.com. This site does the similar calculations for which chargers you need to stop and also allows you to add waypoints if you want to stop at specific locations. I used the site to plan my trip to Florida.

Also, beware the Tesla trip planner in the car still has its quirks. It flat out refused to route us through a convenient charger in Paramus, NJ thanks to the new Supercharger availability detector:

This had us quite concerned as we were already pretty committed to going in that direction. A quick call to the Tesla store at that charger site revealed that theres nothing wrong with the charger. Evidently the charging speeds are slow after 10pm due to some ongoing battle between Tesla and the local power company where their power is being dropped off at night. As long as we were visiting before 10pm we were clear to use the charger. A lot more information needs to be conveyed with these popups.

Tesla needs to continue to invest in and improve the Navigation system.

Calculating a long road trip

At the time I planned the trip, EVTripPlanner did not yet add in charging times and while I knew I needed to time for charging I severely underestimated the amount of time that charging adds to the trip.

If you plan the same trip now that EVTripPlanner has added the expected charging times you’ll find that for the 21 hour drive you’ll add 8 hours and 48 minutes of charging with 11 Supercharger stops each way. So your 21 hour drive turns into a 30 hour drive or is 43% longer. Thats a significant time addition to a long drive.

Charging adds up to 40% to your travel time.

When I did the math myself I used an average of 30 minutes per stop. The problem with that approach is somewhere along the way I did the math wrong and things didn’t add up right. Perhaps I missed a leg somewhere along the way. More on that later.

EVTripPlanner doesn’t currently provide an “elapsed time” or “time of day” readout and the data is difficult and messy to get out of the site to use in Excel or Google sheets.

Planning Mistake 1 – Cold pack

On the way down I couldn’t leave until 2pm, so we left and ultimately hit East Coast traffic for rush hour. This added time to the drive but fortunately doesn’t use extra range as EVs are even more efficient when moving slowly. Between the traffic and the expected charging stops we got to the hotel in Woodbridge, VA quite late. Rather than charging up for the next day that night, we decided to hit the sack and charge up in the morning. This was a mistake.

It got down to about 40 degrees overnight and I had intentionally picked a hotel near a Supercharger. The next morning when we went to charge the charge was more than 30% slower than average. The reason for that is that cold battery packs don’t charge as fast as warm battery packs, something I already knew but hadn’t considered late at night. We would have been better off charging the night before when our battery was warm. That or driving for a while before charging would have been good if we had enough charge to do that.

Plan to charge when your battery is warm. Charge before you go to bed.

Planning Mistake 2 – Charging Speeds

While we know that Tesla’s charge rate of 170 miles in 30 minutes is an ideal number and subject to many factors, we found out the hard way that not all chargers can deliver this. Specifically, despite a warm pack and ideal charging conditions we found that some of the chargers are significantly slower than others. While not as bad as trying to charge on a cold pack, we experienced up to 25% slower charging speeds on some chargers versus our average.

Not all charger can achieve the ideal target of 170 rated miles added in 30 minutes.

With the slower chargers and eliminating the one cold pack charge, our average charge rate was 120 rated miles added in 30 minutes (240 rated miles added per hour) which is significantly lower than Tesla’s number.

You will average worse than 170 rated miles added per 30 minutes which adds time to the trip — plan for it.

Planning Mistake 3 – Round Trips

Our average Supercharger stop time was 34 minutes. While Tesla and EVTripPlanner recommended 11 Supercharger stops, we made 12. The reason being that we needed to get home too. It wasn’t enough to arrive at a condo in Florida with a low charge and then hope to find charge nearby (not many options in that area) to get back to the Supercharger network for the trip home.

So we added one more charger and charged up enough for driving around town for a week and to get back to that charger on the way home. This added time.

Planning Mistake 4 – Margins

Tesla has been adjusting the trip planner over time. In the early days it wasn’t possible to route via Superchargers and then they added it but it was very conservative and often buggy. They’ve continued to make updates to it (although slowly) and now it is a lot more aggressive. For most of my legs it was calculating routes that had me arriving at the next charger with margins in the 11-12% range — thats about 32 miles of safety.

Teslas charge faster from a lower starting state of charge. Charging from 0 to 50 is a lot faster than charging from 20 to 70. So generally you want to arrive at the next charger with as low a state of charge you’re comfortable with and charge just enough to get to the next stop safely.

To keep things moving along and not lose time you need to watch your charge and hop back in the car as soon as the car says you’re safe to get to the next stop. Any more time is wasted and unnecessary charging and a higher state of charge (slower charging) for your next charge.

Under ideal circumstances Tesla’s margin would be fine and Tesla takes into account temperature and elevation changes. The problem is they don’t factor in wind or driving speeds.

Tesla doesn’t factor in all things that affect range.

I typically drive about 5mph over the speed limit. These days this classifies me as a “slower” driver but its what i’m comfortable with. In MA that means driving about 70mph on he highways but down towards Florida you’re doing 75 and still considered slow. After one of the recommended charging stops the car was predicting us arriving with a 12% charge remaining, but then it started to drop. 12% went to 11%, then 10%, then all the way down to 8%. There were no other chargers along the way and the estimated remaining charge was dropping rapidly and we were getting concerned. I dropped my speed from 75 to 65 and slowly the trend reversed and we got to the charger with 9% remaining (24 rated miles).

When planning fails, slow down!

From then on, each time we charged when it said charge to an estimated 12% remaining for the next step, we wanted to wait a few more points “for safety”. Each additional bit of charge is lost time and we were trading our peace of mind and comfort for travel time.

Add time for your comfort margin.

Planning Mistake 5 – Calculate twice, drive once

On the second day of driving we were making good progress, but as the day went on we realized that rather than getting to Tampa around midnight it would be more like 3am and we’re not the kind of drivers that like driving late at night. Fortunately a quick call back to my wife who was in front of a computer got us a hotel reservation and off the road before it got too late.

Somehow along the way the calculations were off by 3 hours. I suspect I missed a leg and a stop and then the extra charging times caught up with us too.

Since there really is no single system to help plan the entire trip this is an easy mistake to make. I should have spent a bit more time double checking my planning before taking off.

Other things

A few other things I wanted to  mention. First, as you drive from charger to charger on a long road trip a common question is “Whats at the next stop?” That question is still pretty painful to answer. You’d think you could just click on the charger icon and like Teslamotors.com it would show the amenities, but it doesn’t. Apps like Teslarati’s own app are useful but its several clicks and scrolling to get to the information and you’re supposed to be driving. A simple page allowing easy access to nearby supercharger details or next charger would be very helpful on a trip like this. Was there a Chick-fil-A at the next stop or just another terrible Texas Roadhouse? We had to know!

We also experienced a wide range of charger types. From the usual 8 in a row, back in variety, to those where you pull head in in an airport parking garage and have to get your parking ticket stamped:

There were also those those with poorly painted lines providing no clue where/how you back into them — side ways or straight back the port didn’t line up.

All this so I could introduce my Tesla to a palm tree for the first time:

And get in a few bike rides while New England tried to thaw out:

Summary

Before this trip I had dozens of Tesla road trips under my belt and have visited chargers in many states at all different times of the year. I was very familiar with the mechanics of an EV road trip, charging times and what to expect. My friend wanted to go to Florida around the same time and had never taken a road trip in an EV before. I warned him up front about the charging times and he assured me it was not a problem.

By the end of the trip he said he didn’t regret taking the trip, but next time he’d take an ICE car or fly — adding 40% to your travel time is unacceptable if you’re trying to get somewhere and not just touring the country. It was hard to argue with him.

While records have been set by cross country teams in Teslas, those are usually multiple driver events with them driving straight through with very little down time and that style of driving isn’t for everyone.

For myself, I still dream of driving across the country to California someday in my Tesla. I need to rest up first as the FL trip took quite a bit of my desire away for a while. Also i’m worried that once I get there I wouldn’t want to drive all the way back home :p

If you do plan to do a longer road trip, spend extra time in the planning phase. New tools and sites continue to be developed to simplify the process, but make sure you’ve had some experience with shorter trips first. With good planning and a relaxed approach you can still be jumping for joy at the end of a successful long road trip in your Tesla.