User-Centred Design of the Public EV Charging Experience

The problem

Public charging is often frustrating: hard-to-read screens, heavy cables, connectors out of reach for wheelchair users or shorter people, poor lighting and unclear payment. Most charger design focuses on power electronics, while user experience is treated as an afterthought. A user-centred design study that combines field research, ergonomics and product design can produce evidence on what improves the experience.

Objectives

• Study real charging sessions through observation and interviews, with ethics approval.
• Build journey maps and identify pain points and accessibility barriers.
• Define design requirements using anthropometric and accessibility data.
• Develop charger concepts in Alias and SOLIDWORKS and build a full-size mock-up.
• Run usability tests comparing the baseline and redesign and analyse results statistically.

What you need

Key concepts

Journey map

A step-by-step view of what a user does, thinks and feels across a task, such as finding, starting, waiting for and ending a charge.

Inclusive design

Designing for the widest range of users, including people using wheelchairs, older users and people with low vision, rather than an average user.

System Usability Scale

A widely used ten-item questionnaire that gives a usability score from 0 to 100 for comparing designs.

Within-subjects test

Each participant tries both designs, in counterbalanced order, which reduces the effect of differences between people.

Step-by-step guide

1. 1

   Review and plan with ethics

   Review literature on charging user experience, inclusive design, accessibility guidance for public equipment and usability methods. Write research questions such as: which design changes reduce task time and errors for diverse users at public chargers? Prepare a study protocol with recruitment, consent, data protection and safety, and obtain ethics approval from your institute before any fieldwork. Pilot the interview guide with two or three people first and revise any questions that confuse them.

   Checkpoint: Ethics approval obtained, with a protocol covering consent, data handling and safety.

2. 2

   Observe and interview

   Observe charging sessions at several public sites with permission from site operators, noting steps, delays and errors without recording identifiable images unless consented. Interview users of different ages and abilities, including at least some wheelchair users or older drivers if possible. Record what they find hard, such as cable weight, reach, screen glare and payment. Store notes and recordings securely and anonymise them early, following the data handling plan in your approved protocol.

   Checkpoint: Observation notes from several sites and interviews with a stated number of diverse participants.

3. 3

   Map journeys and pain points

   Build journey maps from arrival to departure for different user groups. Code interview data into themes with a clear method, such as thematic analysis, and count how often each pain point appears. Rank pain points by frequency and severity. Link each one to a physical design element, a software element or a site issue, and select those your design can address.

   Checkpoint: Journey maps and a ranked pain-point list, each linked to a design element.

4. 4

   Define requirements

   Turn pain points into requirements with measurable targets: holster and screen heights within reach ranges for standing and seated users from published anthropometric data, cable reach to inlets on either side of a parked car, screen readable in sun, lighting levels at night and maximum force to remove the connector. Note any accessibility standards you follow and that they should be checked for current editions.

   Checkpoint: A requirement table with measurable targets and their sources.

5. 5

   Generate concepts

   Sketch concepts in Alias Paint or on paper that address the top pain points: lower angled holsters, a cable retraction or overhead management arm, a tilted screen with a hood, ground lighting and clear step indicators. Build quick form models in Alias with Skin and Rail surfaces, checked with Zebra for visible faces. Review concepts with a few users using renders from VRED or KeyShot.

   Checkpoint: Three concepts with user feedback notes and one or two selected for the mock-up.

6. 6

   Package in SOLIDWORKS

   Import the chosen Alias surfaces into SOLIDWORKS and build a packaging assembly with an example power module envelope, cable path and service access. Create configurations for different holster and screen heights. Check reach with simple human figure models at different percentiles, seated and standing, and confirm targets from the requirement table. Also check cable reach to an inlet on the far side of a parked car using a simple vehicle envelope, since this is a common complaint in the field.

   Checkpoint: Configurations that meet the reach targets for the stated range of users, shown in screenshots with figures.

7. 7

   Build the mock-up

   Design an adjustable full-size mock-up in SOLIDWORKS with a frame from Weldments or plywood panels, so screen and holster heights and angles can be changed. Use printed or foam parts for the holsters and screen surround, and a real or dummy connector with a cable of realistic weight. Add a simple screen with a clickable prototype on a tablet. Build a baseline mock-up representing a typical current charger.

   Checkpoint: Baseline and redesign mock-ups built, with adjustment ranges checked against the CAD.

8. 8

   Run usability tests

   Recruit a diverse group of participants, including people who use wheelchairs where possible, with consent. Use a within-subjects design with counterbalanced order. Give tasks: start a charge, connect to an inlet on the far side of a car, end the session and stow the cable. Measure task time and errors, and collect System Usability Scale scores and comments. Keep conditions consistent between sessions.

   Checkpoint: Complete data for all participants on both designs, with protocol deviations recorded.

9. 9

   Analyse and iterate

   Analyse task times and errors with paired tests suited to the data, such as a paired t-test or Wilcoxon signed-rank test, and compare SUS scores. Report effect sizes and confidence intervals, not only p-values. Look at results for different user groups, noting small sample sizes. Use findings to refine the design, and if possible run a short second round. Present individual participant results as well as averages, since a design that helps most users may still fail one group.

   Checkpoint: Statistical comparison with effect sizes, subgroup observations and a refined design.

10. 10

    Report and share

    Write the thesis chapter or paper: literature, ethics, field research, journey maps, requirements, concepts, CAD, mock-ups, usability results and limitations, such as mock-up realism and sample size. Present design guidelines linked to evidence. Share anonymised data where your approval allows. Avoid claims beyond what your participants and sites support. Thank participants and site operators, and offer them a short plain-language summary of the findings.

    Checkpoint: A report with evidence-linked guidelines, limitations and anonymised data.

Testing & validation

• Ethics approval is in place before fieldwork.
• Requirements are linked to observed pain points and published reach data.
• Mock-ups match the CAD and adjustment ranges are checked.
• Usability tests use counterbalanced within-subjects design.
• Results are reported with effect sizes, confidence intervals and limitations.

Expected results

Evidence on public charging pain points from field research, journey maps and requirements, a redesigned charger concept in Alias and SOLIDWORKS, a full-size adjustable mock-up and usability test results comparing it with a baseline.

Take it further

• Study night-time use with lighting variants in the mock-up.
• Test a cable management arm for heavy DC cables.
• Run a field pilot with a charge point operator using a modified real charger.

Viva and review questions

Learn it at DIYguru

These DIYguru courses and programmes teach what this project needs.