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Tesla Tech – Range Anxiety is Real

One of the things people talk about with electric vehicles is the concern you might have about whether you’ve got enough battery charge in your car to make it to your destination. They call this range anxiety.

With an internal combustion engine (ICE) vehicle, you usually have lots of options to stop and get gas, and getting gas is a matter of maybe 10 minutes, including a bio break. But with an EV, you have to make sure there is a charging station on your path and you need to make sure it will charge you up enough in a reasonable length of time.

I wrote a Tesla Tech article entitled How Long Does it Take to Charge? in which I discussed all of the variables that go into answering that question. I think that long list of variables adds to range anxiety.

I have to confess that I downplayed range anxiety at first, and assumed I would just be able to come up with some easy assumptions and algorithms to ensure anxiety-free road trips. The problem is data-driven, so it should be a cake walk for me. But I was wrong. The more I drive the Model 3, the more range anxiety I am getting because I haven’t cracked the code yet. I have a master’s degree in engineering remember, so if it’s hard for me, how do normal people do this?

I’ll walk you three road trips we’ve taken in the last six months, and how they affected my range anxiety.

  1. Fresno to Nancy to home
  2. Las Vegas with Joe
  3. San Diego to Long Beach to Newport to Long Beach to LA

Fresno to Nancy’s to Home

We drove to Fresno last October to visit Steve’s parents. Fresno is around 230 miles from our house in LA. The particular model of Tesla I bought has a max range of 310 miles. We all remember the line, “your mileage may vary”, but let’s assume 310 is a good baseline assumption of range of this vehicle anyway.

I have a home Tesla wall charger that adds 33 miles of range in an hour, or 33mph. At that rate I can charge it completely over night. It’s not good for this type of battery to be charged to 100% all the time, so they give you an onscreen slider to choose 100% for road trips or say, 80% for day-to-day charging. For our Fresno trip we chose 100%.

While we believed we could easily make it to Fresno on that single charge (230 miles of driving on a 310 mile charge), we didn’t want to wind up in Fresno with an empty battery, so we stopped for a snack and charged up midway there and then were able to toodle around town while we were in Fresno. The problems arose when we drove home.

Before we left the Fresno area, we went to the local Tesla Supercharger where you can charge at up to 500 mph (at least for the first 70% where the charge curve is linear) and did a little shopping at the local mall. I forget how high we charged it up but I think it was around 90%.

According to mad skills at subtraction, I should have had more than enough charge to easily drive from Fresno to our friend Nancy’s house to pick up Tesla (the dog, not the car) and then drive the rest of the way home. But just to be on the safe side, we stopped at a Supercharger about halfway home to top it off.

When we plugged in, we saw the speed of charge ramp up to the expected 500mph for a Supercharger, but then it went past 500 to 600 then 700 … and then it stopped. Confused, we pulled out the charging cable, put it back in and it happened again. We assumed it was a broken charger, so we moved to a new one, and the same thing happened. We tried a 3rd one, same problem. We were angry that so many chargers appeared to be broken. Finally we moved to a stall where someone had just been successfully charging and that one worked. While we were relieved to finally be able to charge, you can imagine that this incident reduced our confidence that we would always be able to get a charge.

Fun story, though: the driver of the Tesla next to us got out of the car and it was the actor Larry David, best known for the TV show Curb Your Enthusiasm. He walked into the same restaurant I was going into, so I was behind him, and he let the door slam in my face. Oh well.

We had lunch and stayed over an hour charging the car, and watched Andy Griffith on the Tesla screen using Netflix. It was actually quite a lovely way to have lunch.

I think I’m learning that this is the wrong strategy. Not the Andy Griffith part, the long charging time. Sitting there for an hour or more is a waste of time. It makes more sense to stop a few times for 20-30 minutes to charge because you’re on the sweet part of the curve where you gain a lot of energy for a small amount of time. After a half hour, you’re not gaining enough to be worth the time spent.

Range vs Energy graph w annotations
Two Drastically Different Indicators of Range

Back on the road, we started to watch the range we had for our trip. Let’s talk about how you know that range when you’re in a Tesla Model 3. There are two separate indicators. Next to the speedometer readout, there’s a little bar graph that looks like a normal computer battery bar that says how many miles you can go.

There is also an energy icon in the onscreen menu that gives you a pretty graph called consumption. The vertical access is your energy consumption in Wh/mi, and it graphs the data over the last 5 miles, 15 miles or 30 miles. At least I assume “mi” means miles not minutes.

On this same graph, you also get a dotted line showing your projected range. As we were driving home, I looked at both versions of the range, and the little battery symbol said 203 miles which was plenty of range, but the consumption graph showed 122 miles!

Now I get that there’s a lot of variables in these calculations so absolute precision is not expected but having the main indicator show me 66% more range than the consumption graph is terrifying. Which one is right?

As of this point in the trip, we had been pretty much driving on flat ground, but ahead of us, we had a pass through the mountains on Interstate 5 called The Grapevine, which would be a climb of 4,000 feet. As we started up The Grapevine, I saw our Wh/mile consumption climbing and that range number dropping and it looked like we might not make it.

But after we got over the pass and started to go downhill, the consumption rate plummeted and the range went to 999 miles. Well that’s super helpful now, isn’t it? Of course we could go a thousand miles as long as we were coasting.

We eventually got back on flat ground, and according to the battery bar, we would easily make it to Nancy’s … but not make it home from her house. Good grief! We stopped again and charged. We ended up hitting LA rush hour traffic because of all the charging stops so the trip took 7 hours when it should have maybe taken 5.

Lessons learned: short booster stops, and watch the graph obsessively to make yourself crazy.

Las Vegas with Joe

We drove the Tesla to CES in Las Vegas this year for the first time. It’s 286 miles from our house to Las Vegas with a pass or two over 4,000 feet. We discussed our EV planning with our buddy Ron, who had driven his Tesla Model S to Vegas a couple of weeks before. He suggested a few places for Tesla Super Chargers along the way and one in Las Vegas he recommended.

We stopped on the way in Baker, had a quick 30 min lunch at El Pollo Loco while the car charged up and ended in Las Vegas with 11%. Looks like we have it figured out now, right?

Well, maybe not. While we were in Vegas, we hung out with our good friend Joe Lagreca. He’s been contemplating getting a Tesla for his wife and he was super interested in seeing the car and how things worked. We decided to drive the car rather than our usual Uber when we went out to dinner about 12 miles away.

The indicator said we had enough miles of range to make the round trip, but with the variability we’ve run into, we didn’t trust it. We decided to go to the Tesla Supercharger next to the Linq Hotel. This was the one Ron told us about. He explained that there’s a secret code you need to find on the screen in your car and you enter it into a keypad at the entrance to the Supercharger. Made me feel special like we were in the “in” crowd.

We plugged in one of the chargers. Remember the problem we had coming back from Fresno where the charge rate went up to 700 mph and then stopped? That happened again. We tried it again and again it stopped and said “check equipment”. For grins and giggles I blew in the connector like you do with a game cartridge from the 90s but inexplicably, that didn’t fix it.

We tried 3 more stations and all of them had the same behavior. Note there were about a dozen people at other stations happily charging away. We even tried one that a guy had just been using to charge and it still failed. We’d burned up a lot of the time we had for charging so we were getting anxious. We noticed there were some regular home chargers, so we tried one of those and it worked, but those charge at around 35 mph so it wasn’t going to be of much help.

At this point Joe made an observation. He said he noticed that each time we tried to use the Supercharger, in the few minutes before it failed, we were actually gaining about 5 miles. He suggested that we could just try it over and over again and gain range faster than sitting on this dumb home charger. We gave his idea a try and not only did it charge 5 miles each attempt, after about 4 times it actually started to charge normally.

While we were on this last attempt, I called Tesla to ask their advice. The dude on the phone told me that the entire station was off line and that’s why I couldn’t charge. I pointed out to him the other dozen people who were successfully charging, but he said he couldn’t see the station so there was nothing he could do.

I told him that possibly my car was having the problem, not the charger and asked him to tap into it and run a diagnostic or something. We know Tesla can see what our car is doing, right? But he said he couldn’t do that because the station was offline. I was understandably upset and told him I wanted a manager to call me back. He said I’d get a call in the next 24-48 hours. That was in January and I still haven’t received the callback from Tesla.

The only good news was that we ended up talking to a guy who was charging and he showed us a cool app and gadget for the Tesla but I’ll tell you about that on another day.

We did make our dinner, but this wasn’t exactly a relaxing experience and you can imagine how much my range anxiety ramped up. Also of note, I don’t think Joe is quite as excited about buying his wife a Tesla as he was before.

San Diego to Long Beach to Newport Beach to Long Beach to LA

My final example might shed some light on my issues with predicting the range of my vehicle. We were in San Diego playing with Lindsay and Nolan and Forbes this weekend. By playing, I mean Steve installed a smart Ecobee thermostat and a Rachio smart sprinkler system while I did drywall repair on a hole in my future granddaughter’s bedroom wall.

We charged the car to 100% (which again should be 310 miles) the night before we left. I told Steve this was overkill, but he insisted. I should listen to him more often. In the morning he made the 3-mile round trip to Starbucks for mochas and a cake pop.

I drove 18 miles round trip to drop off Forbes at daycare. Then we piled up Tesla in the Tesla and drove the 97 miles to Kyle’s house. We met up with Kyle and his wife, and drove 44 miles round trip to Newport Beach for a baby CPR class. Then we drove the 17 miles home to our house. That’s a grand total of 179 miles, on what is supposed to be a 310 mile range vehicle. We should have had 131 miles left.

But the energy consumption graph said that at the rate we’d been consuming, we only had 35 miles left. That means we were short nearly a HUNDRED MILES. I’m ok with “your mileage may vary” but being short by 30% is not acceptable. When we put the car in park, we got an on-screen warning that said, “Battery low. There will be significantly less energy available from your battery if it gets colder. We recommend charging now.”

We have a weather station so I can tell you exactly how cold it was when it said this. It was 48.2°F. That shouldn’t be cold enough to have affected our range by 30%!

Bottom Line

Maybe I am just not clever enough to understand the range of this car. Or maybe there’s something wrong with the car, in which case I need to make an appointment at the Tesla Service Center. Or maybe I need to understand the impact of wind (it was windy), running the air conditioner and heater, running the seat heaters, the external temperature, and the phase of the moon.

See what I mean? Range anxiety is real, people.

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