Cold weather, poor driving habits, and under inflated tyres can all have an impact on electric car range, but it turns out range anxiety is the real reason for electric cars not travelling as far per charge as their manufacturers intended.
That’s the conclusion of Thomas Franke, a doctoral candidate at the Technische Universität Chemnitz in Germany, (via GreenCarCongress) who has examined the data collected by from nearly a quarter of a million miles of logged trips by BMW Mini E drivers in a recent test program in the city of Berlin.
Originally funded by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, the study examined the usage patterns of 79 fleet and private customers over a six month period to better understand their charging and use patterns, with the expressed interest of understanding how charging patterns could fit in with surplus renewable energy generation.
As part of the study, participants kept logs of their user experiences, answered questionnaires, and had their driving patterns monitored by on-board data loggers in each car. While the study itself discovered that a typical German could easily make all the trips they needed in a single day on a single charge of their vehicle, many were plugging in long before their cars were actually empty, or avoiding trips because they were worried about running out of charge.
In his doctoral paper, Franke explains that the degree of discomfort felt by different drivers when approaching the end of their car’s range varied dramatically, proving that as we already know, range anxiety is highly subjective. In the worst cases however, range anxiety caused drivers to artificially limit their drivable range by as much as 25 percent.
“This is caused on the one hand by the competence in dealing with the range – users who have understood the range dynamics of the vehicle can control the range more effectively. On the other hand the question is: How big is the individual preferred safety buffer? ” Frank explains. “In this context, of course, also personality plays a role. For example: Does a user generally believe that he can solve technical problems based on his skills or does he rather believe that this happens by luck or chance.”
As Franke details, most EV drivers do eventually eliminate their own range anxiety given time and experience with the car, with those experiencing most range anxiety when they are inexperienced. Interestingly though, he also notes that most experienced drivers develop three different ways to express their car’s range — seemingly without the use of any on-board range-prediction algorithms: Competent, Preformant, and Comfrotable.
The Competent range is the distance the driver knows they are capable of driving — usually after a bit of trail and error. It’s the distance you know you can go if you concentrate really hard, drive in an extremely eco-minded way, and perhaps keep the heating off. Performant is the distance your car is capable of actually driving, while the Comfortable range is the distance you invariably end up driving without any feelings of range anxiety.
The challenge, Franke says, is to develop ways to help drivers learn and understand the differences in range in all three situations — and use more of their car’s battery pack as a consequence. One suggestion is to include more modes within the car that make it easier to extend range when required by engaging different driving modes. Here at Transport Evolved, we think a ‘reserve’ charge button to access extra capacity when required would be kind of neat, but as Franke hints, one thing is absolutely certain: EVs need a better way of helping drivers understand range and how far you really can go per charge.
Do you have any ideas on how to help drivers maximize the distance travelled per charge in their EV, or do you think it’s always safer to charge when an opportunity presents itself? Or perhaps you have an idea on how automakers could help improve our range expectations?
Leave your thoughts in the Comments below.
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