How Much Range Is Enough?

By  on Clean Technica, 16 Sep 2017

The recent release of the new Nissan LEAF 2 has put the range discussion front and center again. How much range should an electric car have?

And many discussions center around use-case scenarios and mostly around the arguing person’s personal use-case scenario. But these are not important. For a car company, two ranges are important.

  1. How much range is needed for a potential car buyer to consider buying an electric car?
  2. How much range is needed for a car buyer to decide to buy an electric car?

These questions yield different answers for two distinct groups of prospects: Those with the opportunity to charge every night, mostly on their own drive-way, and those who have to go look for a charger every time they need to refill their batteries.

Charging in Your Own Driveway

Looking at the first group, all your arguments about the second question won’t reach the potential customer if she is not willing to consider an electric car. And every number you mention will feel like too little. The trick should be to emphasize the luxury of leaving every morning with a topped-off car. Unconsciously, this will be translate into having a personal gas station at home and leaving each morning after filling up. And make no mistake, this is so different from only filling/recharging when you run nearly dry — that this is the hard part. Because the next question is, but isn’t daily charging bad for the battery?

After opening the prospect’s mind by passing the first question, the second question appears to be three different sub questions.

  1. Is it enough for my daily use?
  2. Can I get home after visiting friends, family, or an event further from home? (This is a round trip distance and comes often on top of the normal daily use.)
  3. Can I travel?

Range for Daily Use

The first is about the kind of distances the EPA range is measuring — local driving interspersed with short hops on the highway. In practice, three times the widely optimistic estimate about the daily driving is believed to be “enough.” Only after driving an electric car on a daily basis for a while do this question and individual answers get viewed more realistically. Every electric car owner trying to explain how little is enough to skeptical family members, friends, and acquaintances knows what doubts have to be overcome.

Range for Extra Visits, a Day Trip

The trips behind the second question can have more highways at higher speeds than the EPA takes into account, making the EPA rating a bit optimistic. These use cases are different for everyone — they can certainly result in not buying the car or creating an excellent excuse to not to visit your in-laws anymore.

Charging while Travelling

The third question is the hardest, debated vehemently, and the numbers mostly hidden. This is what the German environment minister of North Rhine-Westphalia found out about using a Tesla for his daily use. His driver was tasked with charging the car while the minister was in his meetings. After a few months, the conclusion was that there was too much planning and compromising due to the limited range and the lacking charging infrastructure to make this work. A Tesla Model S 90D was not yet up to the task.

For the range while travelling, we have to use completely different numbers. Assume we leave home with a full charge, travel until ~10% is left, charge to 80%, travel second leg, charge to 80%, etc. (As many experienced electric car travelers can tell you, the charge speed drops significantly above 80%.)

I have made a table using the Tesla website and some math. These distances use 100% of the battery charge.

Speed Distance in km / miles
km/h or mph generic 60kWh Model S 75D Model S 100D
70 / 43 456 / 283 584 / 363 744 / 462
80 / 50 414 / 257 532 / 331 678 / 421
90 / 56 373 / 232 481 / 299 612 / 380
100 / 62 335 / 208 432 / 268 551 / 342
110 / 68 300 / 186 388 / 241 496 / 308
120 / 75 269 / 167 348 / 216 446 / 277
130 / 81 241 / 150 312 / 194 401 / 249

For the first leg, we can use 90% and each following leg only 70%. And for the sake of argument, I presume that charging will take no more than 20 minutes. Travelling at less than 100 km/h or 65 mph on freeways is considered hypermiling by many. More normal are speeds of 120–130 km/h or 75–85 mph.

With a 60 kWh car, the first leg would be 217 km /135 miles at 130 km/h, the second and each following leg would be 170 km / 105 miles.

Let us look at the same table, but this time with the second leg in minutes.

Speed Distance in minutes with 70% battery use
km/h or mph generic 60 kWh Model S 75D Model S 100D
100 / 62 141 181 231
110 / 68 115 148 189
120 / 75 94 122 156
130 / 81 78 101 130

In other words, even with a Model S 75D and Supercharging, driving at 120 km/h (75 mph) — typical highway speeds — after your first stop to charge, you will have to charge every 2 hours if you want to spend just ~20 minutes charging and don’t want to go below a ~10% battery charge. That’s not too bad, but if you drop the battery capacity significantly or remove the Supercharging, well … let’s not go there.

I know this is an excellent argument for travelling at a more sedate pace. But we are looking at the arguments a carmaker needs to convince a prospective car buyer. Tesla’s argument is a convincing “Yes, you can!”

For the other carmakers, who do not have access to supercharging, the answer is a cautious “It is an exciting adventure?”

Those Who Have No Place to Charge

At the beginning of this article, there were two questions and the targeted prospects were divided into two segments. What arguments does a carmaker need to get electric driving considered by those who cannot charge every night or have workplace charging. For these prospects, the carmakers have to come with arguments that do not mention range to open the conversation about electric driving. Here, “fun to drive” and “low operating costs” are the leading arguments, with the environmental benefits as supporting arguments.

And then follow the same three questions with a slight difference.

  1. Is it enough for my daily use?
    And how often do I have to find a charger?
    And how long will those charging sessions take?
  2. Can I get home after visiting friends, family or an event further from home. (This is a round trip distance and comes often on top of the normal daily use.)
    And how much charge will I have when I get home?
    And when will I need to leave in the morning to charge enough on the way to work?
  3. Can I travel.

Daily Charging Where & When You Can Find It

And here we see big differences between the reactions of carmakers to that first question.

GM’s CEO Mary Barra thinks it is not her company’s business.

Carlos Ghosn’s Renault-Nissan Alliance has initiated the placing of thousands of chargers by municipalities, utilities, and startups that are building the public charging infrastructure.

Elon Musk has tweeted about the creation of urban charging stations with more stalls but with a lower rate of charge than the Superchargers Tesla has been building along the main highways.

For those who have no place to nightly/daily charge their electric car, the EPA range is much more important. It changes from the argument that you can forget about the range for your daily driving to the parameter that guides you on how to organize the charging for your daily driving.

The answer to the other two questions are mostly the same as for those who have a place for daily charging, but these drivers again have to be more cognizant of their range and next-day charging needs when planning such trips.

Finally, how much range do you need to sell a car?

Coming back to the initial questions, how much range should an electric car have, and whether Nissan is smart or foolish to offer only 150 miles while Tesla and GM have 220+mile models, let’s decide.

For those who do not have their own place to charge, the Chevy Bolt has more flexibility in when and how much to charge. For those who can charge at home, the new LEAF has a large cost advantage without surrendering much on usability — but, ymmv.

Neither car has the option for Supercharging, making long-distance travelling an “adventure.” Possible to do for those who like it, but a big No-No for most of us.

What is possibly the most surprising conclusion is that without Supercharging the difference between enough range for the LEAF 2 and plenty of range for the Chevy Bolt is really not that big a deal. It will make a difference for some buyers, but going beyond 150 miles (240 km) of range for daily use is not that frequent of a need — far from it. Most people can understand that their daily driving needs are well below 40 miles (65 km). But once you start discussing long-distance travel, the lack of superfast charging hinders them both in a similar way.

Images by NissanTeslaTesla Shuttle, and Cynthia Shahan