Wireless charging has been introduced for drivers of 20 electrical vehicles that serves the public sector in Sweden. A longitudinal survey that stretches over 1 year has identified the possible challenges and effects of wireless charging.
It has been shown that the technology has the possibility to overcome barriers of adoption of electric vehicles as the attractiveness for electric vehicles initially increases with inductive charging. It is also shown that the charging pattern may change as the parking time required to feel motivated to start the charging is lower with inductive charging compared to using a cord. Furthermore, it is highlighted that concerns of safety may not become a barrier for using the technology.
The charging cord can be perceived as a barrier for electric car buyers and it is envisioned that wireless charging may provide a significant contribution for the adoption of electric vehicles.
The study consists of 4 digital surveys sent out during a 12-month long test period of the technology. Additional interviews have been performed with key personnel/users of the participating organisations to capture further information. The study was set up as a comparative study in which the first survey captured the experience of using the cord while the following three captured the experience of wireless charging. The study highlights the following questions: with wireless charging (1) will electric cars become more attractive? (2) Is the charging pattern changed? (3) Do safety become a hinder for adoption?
A total of 14 locations in the south of Sweden installed had 1 to 6 charging spots installed to enable wireless charging, ending up at a total of 20 equipped vehicles. Most vehicles were accessed via a car pool set up, and both new and recurrent drivers were included in the study. The vehicles were used for transport between locations with a typical range of 20-30km/day. The typical driver used the vehicle 1-2 times/week. The most drivers had to depend on the vehicles for executing their daily work, while they may not have chosen themselves to take part in this project. That is, the user group is characterised as “early majority” or “late majority” as according to the Innovation Adoption Curve.
Current users of cord charging express: ”It’s much easier than you think to charge with cable, but it is not so fun in the winter when it´s snowing and it’s cold and you have to take off your gloves and enter a code or swipe your charging card…”
The survey focused on the subjective experience of charging using a six-graded-Likert-scale in which the drivers were asked to grade their experience and attitudes towards the charging equipment. A total of 212 answers has been collected (Q1:65; Q2:56; Q3:46; Q4:45). As the vehicles, have been used in a car pool setting with no control over who has been using the vehicles, there are only 10 people that has answered all questionnaires. The analysis has been performed from three perspectives: the individual questionnaires (Q1-Q4), the location of the technology and the drivers that have answered all questionnaires (N=10).
The questionnaire indicates that the attractiveness of electric vehicles is higher for inductive charging. However, after the first questionnaire regarding wireless charging the attractiveness is reduced. The interviews indicate the attractiveness is reduced as the drivers are exposed to technical problem with the technology regarding activation related to parking precision. Also, the interview study in which drivers describe the charging process indicates that the single action “put in the cord” has been replaced with two different actions “park correctly over the pad” and “check that the charging has started” for wireless charging; thereby replacing one action with two other types of actions, reducing the initial attractiveness of wireless charging. Moreover, there are indication that the choice and design of the physical parking space for which inductive charging has been installed has been identified as a determining factor for the satisfaction of the technology, and hence, its attractiveness.
Drivers using wireless charging express: “the idea is great …”; “.. you do not need to handle a cord..”; “Inductive charging as such is good. However it is not suitable always and in all locations…”; ”… a better and more forgiving docking of the car would have been good”; “It is difficult to get the car in the correct position at once. It takes some adjustments to get the charging to work”.
Interestingly, we do not see any strong trend regarding correlation between the amount of use compared to how attractive the technology is perceived to be for inductive charging within this user group.
Furthermore, the wireless technology has the potential to change the current charging pattern of electric vehicle. The analysis of the questionnaire indicates that wireless charging has a lower threshold to be activated (a majority indicates <10 min parking time) as compared to cord (a majority indicates >10 min parking time).
In addition, no substantial evidence that safety would hinder the introduction of wireless charging has been found for the studied user group. The questionnaire highlights that the concern for safety is similar for cord charging (Q1: mean 4,93) as compared to wireless charging (Q4: mean 4,33). The interviews exemplify that drivers have knowledge of the technology through the use in everyday equipment (i.e., stove, lamps, toothbrush, etc.). Also, they have a general belief in approved and tested technology which influence their perceptions of safety. However, there were some concern regarding the effect on pacemaker.
To conclude, it can be argued that wireless charging has the potential to play a significant role for the development of electric vehicles. Regarding the studied user group (car pool users) it can be argued that the usability of the technology is important as the participants within the users group constantly changes and, thus, demands a fool proof technology that is easy to learn. The technology cannot become a hinder in their daily work. In particular, the study highlights that it may be challenging to park correctly over the charging pad when the parking space provides challenges for parking which may be found at public parking spaces/garage.